Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the pote...Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the potential to increase the capacity of free-space optical communication systems,with OAM beams acting as information carriers for OAM division multiplexing(OAM-DM).We demonstrate independent collinear OAM channel generation,transmission and simultaneous detection using Dammann optical vortex gratings(DOVGs).We achieve 80/160 Tbit s^(-1) capacity with uniform power distributions along all channels,with 1600 individually modulated quadrature phase-shift keying(QPSK)/16-QAM data channels multiplexed by 10 OAM states,80 wavelengths and two polarizations.DOVG-enabled OAM multiplexing technology removes the bottleneck of massive OAM state parallel detection and offers an opportunity to raise optical communication systems capacity to Pbit s^(-1) level.展开更多
A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were deve...A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were developed. In addition to complementary absorption spectra(300–830 nm) with IT-4 F, the PM6 also has a deep HOMO(the highest occupied molecular) level(-5.50 e V), which will lower the open-circuit voltage(V_(oc)) sacrifice and reduce the E_(loss) of the IT-4 F-based PSCs. Moreover, the strong crystallinity of PM6 is beneficial to form favorable blend morphology and hence to suppress recombination. As a result, in comparison with the PSCs based on a non-fluorinated D/A pair of PBDB-T:ITIC with a medium PCE of 11.2%, the PM6:IT-4 Fbased PSCs yielded an impressive PCE of 13.5% due to the synergistic effect of fluorination on both donor and acceptor, which is among the highest values recorded in the literatures for PSCs to date. Furthermore, a PCE of 12.2% was remained with the active layer thickness of up to 285 nm and a high PCE of 11.4% was also obtained with a large device area of 1 cm^2. In addition, the devices also showed good storage, thermal and illumination stabilities with respect to the efficiency. These results indicate that fluorination is an effective strategy to improve the photovoltaic performance of materials, as well as the both fluorinated donor and acceptor pair-PM6:IT-4 F is an ideal candidate for the large scale roll-to-roll production of efficient PSCs in the future.展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
The pulse energy in the ultrafast soliton fiber laser oscillators is usually limited by the well-known wave-breaking phenomenon owing to the absence era desirable real saturable absorber （SA） with high power toleran...The pulse energy in the ultrafast soliton fiber laser oscillators is usually limited by the well-known wave-breaking phenomenon owing to the absence era desirable real saturable absorber （SA） with high power tolerance and large modulation depth. Here, we report a type of microfiber-based MoTe2 SA fabricated by the magnetron-sputtering deposition （MSD） method. High-energy wave-breaking free soliton pulses were generated with pulse duration/pulse energy/average output power of 229 fs/2.14 nJ/57 mW in the 1.5 μm regime and 1.3 ps/13.8 nJ/ 212 mW in the 2 μm regime, respectively. To our knowledge, the generated soliton pulses at 1.5μm had the shortest pulse duration and the highest output power among the reported erbium-doped fiber lasers mode locked by transition metal dichalcogenides. Moreover, this was the first demonstration of a MoTe2-based SA in fiber lasers in the 2 ltm regime, and the pulse energy/output power are the highest in the reported thulium-doped fiber lasers mode locked by two-dlmensional materials. Our results suggest that a microfiber-based MoTe2 SA could be used as an excellent photonic device for ultrafast pulse generation, and the MSD technique opens a promising route to produce a high-performance SA with high power tolerance and large modulation depth, which are beneficial for high-energy wave-breaking free pulse generation.展开更多
During past several years,the photovoltaic performances of organic solar cells(OSCs)have achieved rapid progress with power conversion efficiencies(PCEs)over 18%,demonstrating a great practical application prospect.Th...During past several years,the photovoltaic performances of organic solar cells(OSCs)have achieved rapid progress with power conversion efficiencies(PCEs)over 18%,demonstrating a great practical application prospect.The development of material science including conjugated polymer donors,oligomer-like organic molecule donors,fused and nonfused ring acceptors,polymer acceptors,single-component organic solar cells and water/alcohol soluble interface materials are the key research topics in OSC field.Herein,the recent progress of these aspects is systematically summarized.Meanwhile,the current problems and future development are also discussed.展开更多
Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achi...Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achieve rapid,optically sectioned,SR observation with hundreds to thousands of time points.However,real-time observation is still out of reach for most SIM setups as conventional algorithms for image reconstruction involve a heavy computing burden.To address this limitation,an accelerated reconstruction algorithm was developed by implementing a simplified workflow for SR-SIM,termed joint space and frequency reconstruction.This algorithm results in an 80-fold improvement in reconstruction speed relative to the widely used Wiener-SIM.Critically,the increased processing speed does not come at the expense of spatial resolution or sectioning capability,as demonstrated by live imaging of microtubule dynamics and mitochondrial tubulation.展开更多
High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky opti...High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.展开更多
Glasses-free three-dimensional(3D)displays are one of the game-changing technologies that will redefine the display industry in portable electronic devices.However,because of the limited resolution in state-of-the-art...Glasses-free three-dimensional(3D)displays are one of the game-changing technologies that will redefine the display industry in portable electronic devices.However,because of the limited resolution in state-of-the-art display panels,current 3D displays suffer from a critical trade-off among the spatial resolution,angular resolution,and viewing angle.Inspired by the so-called spatially variant resolution imaging found in vertebrate eyes,we propose 3D display with spatially variant information density.Stereoscopic experiences with smooth motion parallax are maintained at the central view,while the viewing angle is enlarged at the periphery view.It is enabled by a large-scale 2D-metagrating complex to manipulate dot/linear/rectangular hybrid shaped views.Furthermore,a video rate full-color 3D display with an unprecedented 160°horizontal viewing angle is demonstrated.With thin and light form factors,the proposed 3D system can be integrated with off-the-shelf purchased flat panels,making it promising for applications in portable electronics.展开更多
An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in...An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in alkaline conditions.Herein,we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks(Fe-Zn-SA/NC),which works efficiently as ORR catalyst in the whole pH range.It achieves high half-wave potentials of 0.78,0.85 and 0.72 V in 0.1 M HClO4,0.1 M KOH and 0.1 M phosphate buffer saline(PBS)solutions,respectively,as well as respectable stability.The performances are even comparable to Pt/C.Furthermore,when assembled into a Zn-air battery,the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices.Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers.This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.展开更多
Power conversion efficiency(PCE)of single-junction polymer solar cells(PSCs)has made a remarkable breakthrough recently.Plenty of work was reported to achieve PCEs higher than 16%derived from the PM6:Y6 binary system....Power conversion efficiency(PCE)of single-junction polymer solar cells(PSCs)has made a remarkable breakthrough recently.Plenty of work was reported to achieve PCEs higher than 16%derived from the PM6:Y6 binary system.To further increase the PCEs of binary OSCs incorporating small molecular acceptor(SMA)Y6,we substituted PM6 with PM7 due to the deeper highest occupied molecular orbital(HOMO)of PM7.Consequently,the PM7:Y6 has achieved PCEs as high as 17.0%by the hotcast method,due to the improved open-circuit voltage(VOC).Compared with PM6,the lower HOMO of PM7 increases the gap between ELUMO-donor and EHOMO-acceptor,which is proportional to VOC.This research provides a high PCE for single-junction binary PSCs,which is meaningful for device fabrication related to PM7 and commercialization of PSCs.展开更多
Black phosphorus(BP), a typical mono-elemental and two-dimensional(2D) material, has gathered significant attention owing to its distinct optoelectronic properties and promising applications, despite its main obstacle...Black phosphorus(BP), a typical mono-elemental and two-dimensional(2D) material, has gathered significant attention owing to its distinct optoelectronic properties and promising applications, despite its main obstacle of long-term stability. Consequently, BP-analog materials with long-term chemical stability show additional potential. In this contribution, tin sulfide(SnS), a novel two-elemental and 2D structural BP-analog monochalcogenide, has been demonstrated to show enhanced stability under ambient conditions. The broadband nonlinear optical properties and carrier dynamics have been systematically investigated via Z-scan and transient absorption approaches. The excellent nonlinear absorption coefficient of 50.5 × 10^-3 cm∕GW, 1 order of magnitude larger than that of BP, endows the promising application of SnS in ultrafast laser generation. Two different decay times of τ1~873 fs and τ2~96.9 ps allow the alteration between pure Q switching and continuous-wave(CW) mode locking in an identical laser resonator. Both mode-locked and Q-switched operations have been experimentally demonstrated using an SnS saturable absorber at the telecommunication window. Femtosecond laser pulses with tunable wavelength and high stability are easily obtained, suggesting the promising potential of SnS as an efficient optical modulator for ultrafast photonics. This primary investigation may be considered an important step towards stable and high-performance BP-analog material-based photonic devices.展开更多
Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic mater...Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.展开更多
Since the successful fabrication of two-dimensional(2D)tellurium(Te)in 2017,its fascinating properties including a thickness dependence bandgap,environmental stability,piezoelectric effect,high carrier mobility,and ph...Since the successful fabrication of two-dimensional(2D)tellurium(Te)in 2017,its fascinating properties including a thickness dependence bandgap,environmental stability,piezoelectric effect,high carrier mobility,and photoresponse among others show great potential for various applications.These include photodetectors,field-effect transistors,piezoelectric devices,modulators,and energy harvesting devices.However,as a new member of the 2D material family,much less known is about 2D Te compared to other 2D materials.Motivated by this lack of knowledge,we review the recent progress of research into 2D Te nanoflakes.Firstly,we introduce the background and motivation of this review.Then,the crystal structures and synthesis methods are presented,followed by an introduction to their physical properties and applications.Finally,the challenges and further development directions are summarized.We believe that milestone investigations of 2D Te nanoflakes will emerge soon,which will bring about great industrial revelations in 2D materials-based nanodevice commercialization.展开更多
Electrochemical CO_(2) reduction reaction (CO_(2) RR) offers a practical solution to current global greenhouse effect by converting excessive CO_(2) into value-added chemicals or fuels. Noble metal-based nanomaterials...Electrochemical CO_(2) reduction reaction (CO_(2) RR) offers a practical solution to current global greenhouse effect by converting excessive CO_(2) into value-added chemicals or fuels. Noble metal-based nanomaterials have been considered as efficient catalysts for the CO_(2) RR owing to their high catalytic activity, long-term stability and superior selectivity to targeted products. On the other hand, they are usually loaded on different support materials in order to minimize their usage and maximize the utilization because of high price and limited reserve. The strong metal-support interaction (MSI) between the metal and substrate plays an important role in affecting the CO_(2) RR performance. In this review, we mainly focus on different types of support materials (e.g., oxides, carbons, ligands, alloys and metal carbides) interacting with noble metal as electrocatalysts for CO_(2) RR. Moreover, the positive effects about MSI for boosting the CO_(2) RR performance via regulating the adsorption strength, electronic structure, coordination environment and binding energy are presented. Lastly, emerging challenges and future opportunities on noble metal electrocatalysts with strong MSI are discussed.展开更多
Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels.Herein,a family of lanthanide(Ln^(3+))ions was successfully incorporated i...Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels.Herein,a family of lanthanide(Ln^(3+))ions was successfully incorporated into a Bi:Cs_(2)AgInCl_(6) lead-free double-perovskite(DP)semiconductor,expanding the spectral range from visible(Vis)to near-infrared(NIR)and improving the photoluminescence quantum yield(PLQY).After multidoping with Nd,Yb,Er and Tm,Bi/Ln:Cs_(2)AgInCl_(6) yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f-4f transitions of the Ln^(3+)dopants.Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes.To avoid adverse energy interactions between the various Ln^(3+)ions in a single DP host,a heterogeneous architecture was designed to spatially confine different Ln^(3+)dopants via a“DP-in-glass composite”(DiG)structure.This bottom-up strategy endowed the prepared Ln^(3+)-doped DIG with a high PLQY of 40%(nearly three times as high as that of the multidoped DP)and superior long-term stability.Finally,a compact Vis-NIR ultrabroadband(400~2000 nm)light source was easily fabricated by coupling the DiG with a commercial UV LED chip,and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.展开更多
We report a framing imaging based on noncollinear optical parametric amplification(NCOPA),named FINCOPA,which applies NCOPA for the first time to single-shot ultrafast optical imaging.In an experiment targeting a lase...We report a framing imaging based on noncollinear optical parametric amplification(NCOPA),named FINCOPA,which applies NCOPA for the first time to single-shot ultrafast optical imaging.In an experiment targeting a laser-induced air plasma grating,FINCOPA achieved 50 fs-resolved optical imaging with a spatial resolution of^83 lp∕mm and an effective frame rate of 10 trillion frames per second(Tfps).It has also successfully visualized an ultrafast rotating optical field with an effective frame rate of 15 Tfps.FINCOPA has simultaneously a femtosecond-level temporal resolution and frame interval and a micrometer-level spatial resolution.Combining outstanding spatial and temporal resolutions with an ultrahigh frame rate,FINCOPA will contribute to high-spatiotemporal resolution observations of ultrafast transient events,such as atomic or molecular dynamics in photonic materials,plasma physics,and laser inertial-confinement fusion.展开更多
To design high efficiency polymer solar cells(PSCs), it is of great importance to develop suitable polymer donors that work well with the low bandgap acceptors, providing complementary absorption, forming interpenetra...To design high efficiency polymer solar cells(PSCs), it is of great importance to develop suitable polymer donors that work well with the low bandgap acceptors, providing complementary absorption, forming interpenetrating networks in the active layers and minimizing energy loss. Recently, we developed a series of two-dimension-conjugated polymers based on bithienylbenzodithiophene-alt-benzotriazole backbone bearing different conjugated side chains, generally called J-series polymers. They are medium energy bandgap(Eg) polymers(Eg of ca. 1.80 eV)with strong absorptions in the range of 400-650 nm, and exhibit ordered crystalline structures, high hole mobilities, and more interestingly,tunable energy levels depending on the structure variations. In this feature article, we highlight our recent efforts on the design and synthesis of those J-series polymer donors, including an introduction on the polymer design strategy and emphasis on the crucial function of differential conjugated side chain. Finally, the future opportunities and challenges of the J-series polymers in PSCs are discussed.展开更多
During the last two decades,porous coordination polymers(PCPs),usually called as metal-organic frameworks(MOFs),have been developed rapidly due to their versatile structural diversities and potential physical and chem...During the last two decades,porous coordination polymers(PCPs),usually called as metal-organic frameworks(MOFs),have been developed rapidly due to their versatile structural diversities and potential physical and chemical functions.This article provides a short review of recent advances in the design and constructions of porous coordination polymers based on three planar rigid ligands,including imidazole-4,5-dicarboxlate(H3IDC),1H-tetrazole(HTz),as well as 1H-tetrazole-5-carboxylate(H2Tzc).Their preparations,crystal structures,and desirable properties have been reviewed.展开更多
Herein,we fabricated all-polymer solar cells(all-PSCs)based on a fluorinated wide-bandgap p-type conjugated polymer PM6 as the donor,and a narrow bandgap n-type conjugated polymer PZ1 as the acceptor.In addition to th...Herein,we fabricated all-polymer solar cells(all-PSCs)based on a fluorinated wide-bandgap p-type conjugated polymer PM6 as the donor,and a narrow bandgap n-type conjugated polymer PZ1 as the acceptor.In addition to the complementary absorption and matching energy levels,the optimized blend films possess high cystallinity,predominantly face-on stacking,and a suitable phase separated morphology.With this active layer,the devices exhibited a high Vocof 0.96 V,a superior Jscof 17.1 mA cm^-2,a fine fill factor(FF)of 68.2%,and thus an excellent power conversion efficiency(PCE)of 11.2%,which is the highest value reported to date for single-junction all-PSCs.Furthermore,the devices showed good storage stability.After 80 d of storage in the N2-filled glovebox,the PCE still remained over 90%of the original value.Large-area devices(1.1 cm^2)also demonstrated an outstanding performance with a PCE of 9.2%,among the highest values for the reported large-area all-PSCs.These results indicate that the PM6:PZ1 blend is a promising candidate for scale-up production of large area high-performance all-PSCs.展开更多
The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,...The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.展开更多
基金This work was partially supported by the National Natural Science Foundation of China under Grant numbers 61036013,61138003,61427819,61001101 and 61435006XY acknowledges support from the Ministry of Science and Technology of China under National Basic Research Program of China(973)grant no.2015CB352004.
文摘Data transmission rates in optical communication systems are approaching the limits of conventional multiplexing methods.Orbital angular momentum(OAM)in optical vortex beams offers a new degree of freedom and the potential to increase the capacity of free-space optical communication systems,with OAM beams acting as information carriers for OAM division multiplexing(OAM-DM).We demonstrate independent collinear OAM channel generation,transmission and simultaneous detection using Dammann optical vortex gratings(DOVGs).We achieve 80/160 Tbit s^(-1) capacity with uniform power distributions along all channels,with 1600 individually modulated quadrature phase-shift keying(QPSK)/16-QAM data channels multiplexed by 10 OAM states,80 wavelengths and two polarizations.DOVG-enabled OAM multiplexing technology removes the bottleneck of massive OAM state parallel detection and offers an opportunity to raise optical communication systems capacity to Pbit s^(-1) level.
基金supported by the National Natural Science Foundation of China(51422306,51503135,51573120,91633301)Jiangsu Provincial Natural Science Foundation(BK20150332)T.P.Russell was supported by the U.S.Office of Naval Research(N00014-15-1-2244)
文摘A high performance polymer solar cells(PSCs) based on polymer donor PM6 containing fluorinated thienyl benzodithiophene unit and n-type organic semiconductor acceptor IT-4 F containing fluorinated end-groups were developed. In addition to complementary absorption spectra(300–830 nm) with IT-4 F, the PM6 also has a deep HOMO(the highest occupied molecular) level(-5.50 e V), which will lower the open-circuit voltage(V_(oc)) sacrifice and reduce the E_(loss) of the IT-4 F-based PSCs. Moreover, the strong crystallinity of PM6 is beneficial to form favorable blend morphology and hence to suppress recombination. As a result, in comparison with the PSCs based on a non-fluorinated D/A pair of PBDB-T:ITIC with a medium PCE of 11.2%, the PM6:IT-4 Fbased PSCs yielded an impressive PCE of 13.5% due to the synergistic effect of fluorination on both donor and acceptor, which is among the highest values recorded in the literatures for PSCs to date. Furthermore, a PCE of 12.2% was remained with the active layer thickness of up to 285 nm and a high PCE of 11.4% was also obtained with a large device area of 1 cm^2. In addition, the devices also showed good storage, thermal and illumination stabilities with respect to the efficiency. These results indicate that fluorination is an effective strategy to improve the photovoltaic performance of materials, as well as the both fluorinated donor and acceptor pair-PM6:IT-4 F is an ideal candidate for the large scale roll-to-roll production of efficient PSCs in the future.
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
基金National Natural Science Foundation of China(NSFC)(11704260,61405126,61605122,61775146)Shenzhen Science and Technology Project(JCY20150324141711695,JCYJ20160427105041864,JSGG20160429114438287,KQJSCX20160226194031,JCYJ20160422103744090)+1 种基金Beijing University of Posts and Telecommunications(BUPT)(IPOC2015B003)Natural Science Foundation of Guangdong Province(2016A030310049,2016A030310059)
文摘The pulse energy in the ultrafast soliton fiber laser oscillators is usually limited by the well-known wave-breaking phenomenon owing to the absence era desirable real saturable absorber （SA） with high power tolerance and large modulation depth. Here, we report a type of microfiber-based MoTe2 SA fabricated by the magnetron-sputtering deposition （MSD） method. High-energy wave-breaking free soliton pulses were generated with pulse duration/pulse energy/average output power of 229 fs/2.14 nJ/57 mW in the 1.5 μm regime and 1.3 ps/13.8 nJ/ 212 mW in the 2 μm regime, respectively. To our knowledge, the generated soliton pulses at 1.5μm had the shortest pulse duration and the highest output power among the reported erbium-doped fiber lasers mode locked by transition metal dichalcogenides. Moreover, this was the first demonstration of a MoTe2-based SA in fiber lasers in the 2 ltm regime, and the pulse energy/output power are the highest in the reported thulium-doped fiber lasers mode locked by two-dlmensional materials. Our results suggest that a microfiber-based MoTe2 SA could be used as an excellent photonic device for ultrafast pulse generation, and the MSD technique opens a promising route to produce a high-performance SA with high power tolerance and large modulation depth, which are beneficial for high-energy wave-breaking free pulse generation.
基金supported by the National Natural Science Foundation of China(51933001,22109080,21734009,52173174)。
文摘During past several years,the photovoltaic performances of organic solar cells(OSCs)have achieved rapid progress with power conversion efficiencies(PCEs)over 18%,demonstrating a great practical application prospect.The development of material science including conjugated polymer donors,oligomer-like organic molecule donors,fused and nonfused ring acceptors,polymer acceptors,single-component organic solar cells and water/alcohol soluble interface materials are the key research topics in OSC field.Herein,the recent progress of these aspects is systematically summarized.Meanwhile,the current problems and future development are also discussed.
基金supported by the National Natural Science Foundation of China (NSFC) (Nos. 62005208, 62135003, and 61905189)Innovation Capability Support Program of Shaanxi (No. 2021TD-57)+1 种基金China Postdoctoral Science Foundation (Nos. 2020M673365 and 2019M663656)National Institutes of Health Grant GM100156 to PRB
文摘Super-resolution structured illumination microscopy(SR-SIM)is an outstanding method for visualizing the subcellular dynamics in living cells.To date,by using elaborately designed systems and algorithms,SR-SIM can achieve rapid,optically sectioned,SR observation with hundreds to thousands of time points.However,real-time observation is still out of reach for most SIM setups as conventional algorithms for image reconstruction involve a heavy computing burden.To address this limitation,an accelerated reconstruction algorithm was developed by implementing a simplified workflow for SR-SIM,termed joint space and frequency reconstruction.This algorithm results in an 80-fold improvement in reconstruction speed relative to the widely used Wiener-SIM.Critically,the increased processing speed does not come at the expense of spatial resolution or sectioning capability,as demonstrated by live imaging of microtubule dynamics and mitochondrial tubulation.
基金supported by the National Key Research and Development Program of China(2019YFB1803900 and 2019YFA0705000)National Natural Science Foundation of China(11690031 and 11761131001)+2 种基金Key R&D Program of Guangdong Province(2018B030329001)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X121)Key-Area Research and Development Program of Guangdong Province(2019B121204003).
文摘High-speed polarization management is highly desirable for many applications,such as remote sensing,telecommunication,and medical diagnosis.However,most of the approaches for polarization management rely on bulky optical components that are slow to respond,cumbersome to use,and sometimes with high drive voltages.Here,we overcome these limitations by harnessing photonic integrated circuits based on thin-film lithium niobate platform.We successfully realize a portfolio of thin-film lithium niobate devices for essential polarization management functionalities,including arbitrary polarization generation,fast polarization measurement,polarization scrambling,and automatic polarization control.The present devices feature ultra-fast control speeds,low drive voltages,low optical losses and compact footprints.Using these devices,we achieve high fidelity polarization generation with a polarization extinction ratio up to 41.9 dB and fast polarization scrambling with a scrambling rate up to 65 Mrad s−1,both of which are best results in integrated optics.We also demonstrate the endless polarization state tracking operation in our devices.The demonstrated devices unlock a drastically new level of performance and scales in polarization management devices,leading to a paradigm shift in polarization management.
基金This work was financially supported by the Natural Science Foundation of China(NSFC)(Nos.61975140 and 62075145)Leading Technology of Jiangsu Basic Research Plan(BK20192003)Suzhou Natural Science Foundation of China(SYG201930)。
文摘Glasses-free three-dimensional(3D)displays are one of the game-changing technologies that will redefine the display industry in portable electronic devices.However,because of the limited resolution in state-of-the-art display panels,current 3D displays suffer from a critical trade-off among the spatial resolution,angular resolution,and viewing angle.Inspired by the so-called spatially variant resolution imaging found in vertebrate eyes,we propose 3D display with spatially variant information density.Stereoscopic experiences with smooth motion parallax are maintained at the central view,while the viewing angle is enlarged at the periphery view.It is enabled by a large-scale 2D-metagrating complex to manipulate dot/linear/rectangular hybrid shaped views.Furthermore,a video rate full-color 3D display with an unprecedented 160°horizontal viewing angle is demonstrated.With thin and light form factors,the proposed 3D system can be integrated with off-the-shelf purchased flat panels,making it promising for applications in portable electronics.
基金This work was financially supported by National Key R&D Program of China(No.2017YFA0700104)the National Natural Science Foundation of China(Nos.22075211,21601136,51971157,51761165012,and 62005173)+2 种基金Project funded by China Postdoctoral Science Foundation(No.2020TQ0201)Tianjin Science Fund for Distinguished Young Scholars(No.19JCJQJC61800)The authors also acknowledge National Supercomputing Center in Shenzhen for providing the computational resources and materials studio(version 7.0,DMol3).
文摘An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in alkaline conditions.Herein,we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks(Fe-Zn-SA/NC),which works efficiently as ORR catalyst in the whole pH range.It achieves high half-wave potentials of 0.78,0.85 and 0.72 V in 0.1 M HClO4,0.1 M KOH and 0.1 M phosphate buffer saline(PBS)solutions,respectively,as well as respectable stability.The performances are even comparable to Pt/C.Furthermore,when assembled into a Zn-air battery,the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices.Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers.This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.
基金supported by Shen Zhen Technology and Innovation Commission(JCYJ20170413173814007,JCYJ20170818113905024)Hong Kong Research Grants Council(Research Impact Fund R6021-18,16305915,16322416,606012,16303917)+2 种基金Hong Kong Innovation and Technology Commission(ITCCNERC14SC01,ITS/471/18)supported by National Natural Science Foundation of China(51573120,51973146,91633301)Collaborative Innovation Center of Suzhou Nano Science&Technology,and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Power conversion efficiency(PCE)of single-junction polymer solar cells(PSCs)has made a remarkable breakthrough recently.Plenty of work was reported to achieve PCEs higher than 16%derived from the PM6:Y6 binary system.To further increase the PCEs of binary OSCs incorporating small molecular acceptor(SMA)Y6,we substituted PM6 with PM7 due to the deeper highest occupied molecular orbital(HOMO)of PM7.Consequently,the PM7:Y6 has achieved PCEs as high as 17.0%by the hotcast method,due to the improved open-circuit voltage(VOC).Compared with PM6,the lower HOMO of PM7 increases the gap between ELUMO-donor and EHOMO-acceptor,which is proportional to VOC.This research provides a high PCE for single-junction binary PSCs,which is meaningful for device fabrication related to PM7 and commercialization of PSCs.
基金National Natural Science Foundation of China(NSFC)(61435010,61575089)Science and Technology Innovation Commission of Shenzhen(KQTD2015032416270385)+3 种基金China Postdoctoral Science Foundation(2017M612712,2017M612730)Science and Technology Development Fund(STDF)(007/2017/A1)Macao SARChina and the Postgraduate Innovation Development Fund Project of Shenzhen University(PIDFPZR2018004)
文摘Black phosphorus(BP), a typical mono-elemental and two-dimensional(2D) material, has gathered significant attention owing to its distinct optoelectronic properties and promising applications, despite its main obstacle of long-term stability. Consequently, BP-analog materials with long-term chemical stability show additional potential. In this contribution, tin sulfide(SnS), a novel two-elemental and 2D structural BP-analog monochalcogenide, has been demonstrated to show enhanced stability under ambient conditions. The broadband nonlinear optical properties and carrier dynamics have been systematically investigated via Z-scan and transient absorption approaches. The excellent nonlinear absorption coefficient of 50.5 × 10^-3 cm∕GW, 1 order of magnitude larger than that of BP, endows the promising application of SnS in ultrafast laser generation. Two different decay times of τ1~873 fs and τ2~96.9 ps allow the alteration between pure Q switching and continuous-wave(CW) mode locking in an identical laser resonator. Both mode-locked and Q-switched operations have been experimentally demonstrated using an SnS saturable absorber at the telecommunication window. Femtosecond laser pulses with tunable wavelength and high stability are easily obtained, suggesting the promising potential of SnS as an efficient optical modulator for ultrafast photonics. This primary investigation may be considered an important step towards stable and high-performance BP-analog material-based photonic devices.
基金supported by National Science Foundation for Young Scientists of China (No.61905161 and 51702219)the National Natural Science Foundation of China (No.61975134,61875138 and 61775147)+1 种基金the Science and Technology Innovation Commission of Shenzhen (No. JCYJ20180206121837007)the Shenzhen Nanshan District Pilotage Team Program (LHTD20170006)
文摘Thermoelectric generators have attracted a wide research interest owing to their ability to directly convert heat into electrical power.Moreover,the thermoelectric properties of traditional inorganic and organic materials have been significantly improved over the past few decades.Among these compounds,layered two-dimensional(2D)materials,such as graphene,black phosphorus,transition metal dichalcogenides,IVA–VIA compounds,and MXenes,have generated a large research attention as a group of potentially high-performance thermoelectric materials.Due to their unique electronic,mechanical,thermal,and optoelectronic properties,thermoelectric devices based on such materials can be applied in a variety of applications.Herein,a comprehensive review on the development of 2D materials for thermoelectric applications,as well as theoretical simulations and experimental preparation,is presented.In addition,nanodevice and new applications of 2D thermoelectric materials are also introduced.At last,current challenges are discussed and several prospects in this field are proposed.
基金supported by the National Natural Science Fund of China(Grant Nos.61875138,61435010,and 61961136001)Science and Technology Innovation Commission of Shenzhen(KQJSCX20180328095501798,JCYJ20180507182047316,KQTD2015032416270385,JCYJ20170811093453105,JCYJ20180307164612205 and GJHZ20180928160209731)+1 种基金Natural Science Foundation of Guangdong Province for Distinguished Young Scholars(2018B030306038)Natural Science Foundation of SZU(No.860-000002110429).
文摘Since the successful fabrication of two-dimensional(2D)tellurium(Te)in 2017,its fascinating properties including a thickness dependence bandgap,environmental stability,piezoelectric effect,high carrier mobility,and photoresponse among others show great potential for various applications.These include photodetectors,field-effect transistors,piezoelectric devices,modulators,and energy harvesting devices.However,as a new member of the 2D material family,much less known is about 2D Te compared to other 2D materials.Motivated by this lack of knowledge,we review the recent progress of research into 2D Te nanoflakes.Firstly,we introduce the background and motivation of this review.Then,the crystal structures and synthesis methods are presented,followed by an introduction to their physical properties and applications.Finally,the challenges and further development directions are summarized.We believe that milestone investigations of 2D Te nanoflakes will emerge soon,which will bring about great industrial revelations in 2D materials-based nanodevice commercialization.
基金This work was financially supported by National Key Research and Development Program(No.2018YFB1502503)and Sichuan Science and Technology Program(No.2020YJ0299).
文摘Electrochemical CO_(2) reduction reaction (CO_(2) RR) offers a practical solution to current global greenhouse effect by converting excessive CO_(2) into value-added chemicals or fuels. Noble metal-based nanomaterials have been considered as efficient catalysts for the CO_(2) RR owing to their high catalytic activity, long-term stability and superior selectivity to targeted products. On the other hand, they are usually loaded on different support materials in order to minimize their usage and maximize the utilization because of high price and limited reserve. The strong metal-support interaction (MSI) between the metal and substrate plays an important role in affecting the CO_(2) RR performance. In this review, we mainly focus on different types of support materials (e.g., oxides, carbons, ligands, alloys and metal carbides) interacting with noble metal as electrocatalysts for CO_(2) RR. Moreover, the positive effects about MSI for boosting the CO_(2) RR performance via regulating the adsorption strength, electronic structure, coordination environment and binding energy are presented. Lastly, emerging challenges and future opportunities on noble metal electrocatalysts with strong MSI are discussed.
基金This research was supported by the National Natural Science Foundation of China(51972060,U1805252,and 22135008)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information(2021ZZ126)the Natural Science Foundation of Fujian Province(2020J02017,2021L3024).
文摘Impurity doping is an effective approach to tuning the optoelectronic performance of host materials by imparting extrinsic electronic channels.Herein,a family of lanthanide(Ln^(3+))ions was successfully incorporated into a Bi:Cs_(2)AgInCl_(6) lead-free double-perovskite(DP)semiconductor,expanding the spectral range from visible(Vis)to near-infrared(NIR)and improving the photoluminescence quantum yield(PLQY).After multidoping with Nd,Yb,Er and Tm,Bi/Ln:Cs_(2)AgInCl_(6) yielded an ultrabroadband continuous emission spectrum with a full width at half-maximum of~365 nm originating from intrinsic self-trapped exciton recombination and abundant 4f-4f transitions of the Ln^(3+)dopants.Steady-state and transient-state spectra were used to ascertain the energy transfer and emissive processes.To avoid adverse energy interactions between the various Ln^(3+)ions in a single DP host,a heterogeneous architecture was designed to spatially confine different Ln^(3+)dopants via a“DP-in-glass composite”(DiG)structure.This bottom-up strategy endowed the prepared Ln^(3+)-doped DIG with a high PLQY of 40%(nearly three times as high as that of the multidoped DP)and superior long-term stability.Finally,a compact Vis-NIR ultrabroadband(400~2000 nm)light source was easily fabricated by coupling the DiG with a commercial UV LED chip,and this light source has promising applications in nondestructive spectroscopic analyses and multifunctional lighting.
基金supported partly by the National Natural Science Foundation of China(Nos.61775142 and 61705132)the Shenzhen Basic Research Project on the subject layout(No.JCYJ20170412105812811)+1 种基金the Shenzhen Basic Research Projects(Nos.JCYJ20170412105812811,JCYJ20190808164007485,and JCYJ20190808115601653)the Natural Sciences and Engineering Research Council of Canada(Nos.RGPIN-2017-05959 and RGPAS-507845-2017)
文摘We report a framing imaging based on noncollinear optical parametric amplification(NCOPA),named FINCOPA,which applies NCOPA for the first time to single-shot ultrafast optical imaging.In an experiment targeting a laser-induced air plasma grating,FINCOPA achieved 50 fs-resolved optical imaging with a spatial resolution of^83 lp∕mm and an effective frame rate of 10 trillion frames per second(Tfps).It has also successfully visualized an ultrafast rotating optical field with an effective frame rate of 15 Tfps.FINCOPA has simultaneously a femtosecond-level temporal resolution and frame interval and a micrometer-level spatial resolution.Combining outstanding spatial and temporal resolutions with an ultrahigh frame rate,FINCOPA will contribute to high-spatiotemporal resolution observations of ultrafast transient events,such as atomic or molecular dynamics in photonic materials,plasma physics,and laser inertial-confinement fusion.
基金financially supported by the National Natural Science Foundation of China(Nos.51722308,51673200,21734008,and 51820105003)Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302007)Fundamental Research Funds for the Central Universities(No.Buctrc201822,XK1802-2)。
文摘To design high efficiency polymer solar cells(PSCs), it is of great importance to develop suitable polymer donors that work well with the low bandgap acceptors, providing complementary absorption, forming interpenetrating networks in the active layers and minimizing energy loss. Recently, we developed a series of two-dimension-conjugated polymers based on bithienylbenzodithiophene-alt-benzotriazole backbone bearing different conjugated side chains, generally called J-series polymers. They are medium energy bandgap(Eg) polymers(Eg of ca. 1.80 eV)with strong absorptions in the range of 400-650 nm, and exhibit ordered crystalline structures, high hole mobilities, and more interestingly,tunable energy levels depending on the structure variations. In this feature article, we highlight our recent efforts on the design and synthesis of those J-series polymer donors, including an introduction on the polymer design strategy and emphasis on the crucial function of differential conjugated side chain. Finally, the future opportunities and challenges of the J-series polymers in PSCs are discussed.
文摘During the last two decades,porous coordination polymers(PCPs),usually called as metal-organic frameworks(MOFs),have been developed rapidly due to their versatile structural diversities and potential physical and chemical functions.This article provides a short review of recent advances in the design and constructions of porous coordination polymers based on three planar rigid ligands,including imidazole-4,5-dicarboxlate(H3IDC),1H-tetrazole(HTz),as well as 1H-tetrazole-5-carboxylate(H2Tzc).Their preparations,crystal structures,and desirable properties have been reviewed.
基金supported by the National Natural Science Foundation of China (51773142, 51573120, 21734009, 91633301)T. P. Russell was supported by the U.S. Office of Naval Research (N0001415-1-2244)
文摘Herein,we fabricated all-polymer solar cells(all-PSCs)based on a fluorinated wide-bandgap p-type conjugated polymer PM6 as the donor,and a narrow bandgap n-type conjugated polymer PZ1 as the acceptor.In addition to the complementary absorption and matching energy levels,the optimized blend films possess high cystallinity,predominantly face-on stacking,and a suitable phase separated morphology.With this active layer,the devices exhibited a high Vocof 0.96 V,a superior Jscof 17.1 mA cm^-2,a fine fill factor(FF)of 68.2%,and thus an excellent power conversion efficiency(PCE)of 11.2%,which is the highest value reported to date for single-junction all-PSCs.Furthermore,the devices showed good storage stability.After 80 d of storage in the N2-filled glovebox,the PCE still remained over 90%of the original value.Large-area devices(1.1 cm^2)also demonstrated an outstanding performance with a PCE of 9.2%,among the highest values for the reported large-area all-PSCs.These results indicate that the PM6:PZ1 blend is a promising candidate for scale-up production of large area high-performance all-PSCs.
基金supported by the National Natural Science Foundation of China(51673138,51820105003,91633301)the Priority Academic Program Development of Jiangsu Higher Education Institutions+2 种基金the Jiangsu Provincial Natural Science Foundation(BK20160059)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(16KJB430027)the National Key Research and Development Program of China(2017YFA0207700)
文摘The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.
