Room temperature phosphorescence(RTP) has drawn increasing attention for its great potential in practical applications.Polymers with large molecular weights and long chains tend to form coil, which can endow them with...Room temperature phosphorescence(RTP) has drawn increasing attention for its great potential in practical applications.Polymers with large molecular weights and long chains tend to form coil, which can endow them with a high degree of possible rigidity and result in the much restricted non-radiative transition. Also, the intertwined structure of polymers could isolate the oxygen and humidity effectively, thus reducing the consumption of triplet excitons. In consideration of these points, organic polymers would be another kind of ideal platform to realize RTP effect. This short review summarized the design strategy of the purely organic room temperature phosphorescence polymers, mainly focusing on the building forms of polymers and the corresponding inherent mechanisms,and also gives some outlooks on the further exploration of this field at the end of this paper.展开更多
With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors an...With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors and the number of side defects have restricted the practical applications of small sized micro-LEDs.Recently,quantum dot(QD)and nonradiative energy transfer(NRET)have been proposed to solve existing problems.QDs possess nanoscale dimensions and high luminous efficiency,and they are suitable for NRET because they are able to nearly contact the micro-LED chip.The NRET between QDs and micro-LED chip further improves the color conversion efficiency(CCE)and effective quantum yield(EQY)of full-color micro-LED devices.In this review,we discuss the NRET mechanism for QD micro-LED devices,and then nano-pillar LED,nano-hole LED,and nano-ring LED are introduced in detail.These structures are beneficial to the NRET between QD and micro-LED,especially nano-ring LED.Finally,the challenges and future envisions have also been described.展开更多
This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker...This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine(CMA^(+))cation,which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations,compared to the rigid phenethyl methylamine(PEA^(+))analog.It demonstrates a significantly lower non-radiative recombination rate,even though the two types of bulky cations have similar chemical passivation effects on perovskite,which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation.The resulting PSCs achieve an exceptional power conversion efficiency(PCE)of 25.5%with a record-high opencircuit voltage(V_(OC))of 1.20 V for narrow bandgap perovskite(FAPbI_(3)).The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.展开更多
In this work,cubic-phased CeO_(2):18 mol%Yb^(3+)/2 moI%Er^(3+)nanospheres were prepared by coprecipitation method,in which the size of nanosphere was precisely controlled by regulating the amount of coprecipitator ure...In this work,cubic-phased CeO_(2):18 mol%Yb^(3+)/2 moI%Er^(3+)nanospheres were prepared by coprecipitation method,in which the size of nanosphere was precisely controlled by regulating the amount of coprecipitator urea.The morphology evolution of CeO_(2):18%Yb3+/2%Er^(3+)samples that vary from nanosphere to nano-flower with extending the reaction time was elaborately investigated via increasing the amount of urea and increasing the reaction temperature.The influence of non-radiative relaxation(NR)processes and surface quenching on up-conversion emission output of CeO_(2):18%Yb^(3+)/2%Er^(3+)was investigated through varying the sizes and environmental temperatures.Tissue imaging experiment demonstrates that CeO_(2):18%Yb^(3+)/2%Er^(3+)nanospheres have the potential to act as luminescent imaging reagents in tissue imaging.展开更多
In recent years, with the emergence of non-fullerene fused-ring acceptors, power conversion efficiencies (PCEs) of organic solar cells (OSCs) have exceeded 19%.However, compared to inorganic or perovskite photovoltaic...In recent years, with the emergence of non-fullerene fused-ring acceptors, power conversion efficiencies (PCEs) of organic solar cells (OSCs) have exceeded 19%.However, compared to inorganic or perovskite photovoltaic cells, a higher voltage loss has become one of the key factors limiting further improvement in the PCEs of OSCs.The ternary/quaternary strategy has been identified as a feasible and effective way to obtain high-efficiency OSCs.In this review, a brief outline is given of the key roles that guest materials played in reducing voltage losses in solar cell devices and a brief look at the future material design and the design of ternary/quaternary systems.展开更多
Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to...Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to the direct production of CQD inks.However,the photoelectric conversion efficiency(PCE)of lead chalcogenide CQDSCs is presently close to 14%,well below the commercialization target(20%),which is only 41%of the theoretical Shockley-Queisser limit efficiency.In this study,the different losses of open-circuit voltage(V_(oc)),fill factor(FF),and short circuit current density(J_(sc))for current CQDSCs are systematically discussed,as well as the percentage and likely causes of each loss.Then the primary reasons for the CQDSCs’performance constraints are highlighted.Following that,we focus on the CQDSCs interfaces(i.e.,CQD/CQD,CQD/HTL,and ETL/CQD)and explore viable ways to reduce device performance loss.Finally,based on the discussion above,we propose many enhancements to significantly solve numerous major obstacles impeding device performance to boost the PCE of CQDSCs for future commercialization significantly.展开更多
Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination...Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.展开更多
Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamid...Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamide(6Cl)were employed as O-ligands to facilitate the deposition of MAPbI_(3)(MA=methylammonium)and MA-free FA_(0.88)Cs_(0.12)PbI_(2.64)Br_(0.36)(FA=formamidinium)perovskite films by multifunctional anchoring.By density functional theory(DFT)calculations and ultraviolet photoelectron spectroscopy(UPS)measurements,it is identified that the highest occupied molecular orbital(HOMO)level for additive modified MAPbI_(3)perovskite could reduce the voltage deficit for hole extraction.Moreover,due to the most favorable charge distribution and significant improvements in charge mobility and defect passivation,the power conversion efficiency(PCE)of 2Cl-MAPbI_(3)PSCs was significantly improved from 19.32%to 21.12%.More importantly,the two-dimensional grazing-incidence wide-angle X-ray scattering(GIWAXS)analysis showed that PbI_(2) defects were effectively suppressed and femtosecond transient absorption(TA)spectroscopy demonstrated that the trap-assisted recombination at grain boundaries was effectively inhibited in the 2Cl-MA-free film.As a result,the thermally stable 2Cl-MA-free PSCs achieved a remarkable PCE of 23.13%with an open-circuit voltage(V_(oc))of 1.164 V and an ultrahigh fill factor(FF)of 85.7%.Our work offers a practical strategy for further commercializing stable and efficient PSCs.展开更多
Interfacial imperfections between the perovskite layer and the electron transport layer(ETL)in perovskite solar cells(PSCs)can lead to performance loss and negatively influence long-term operational stability.Here,we ...Interfacial imperfections between the perovskite layer and the electron transport layer(ETL)in perovskite solar cells(PSCs)can lead to performance loss and negatively influence long-term operational stability.Here,we introduce an interface engineering method to modify the interface between perovskite and ETL by using multifunctional carbon dots(CDs).C=O in the CDs can chelate with the uncoordinated Pb2+in the perovskite material,inhibit interfacial recombination,and enhance the performance and stability of device.In addition,–OH in CDs forms hydrogen bonds with I-and organic cation in perovskite,inhibiting light-induced I2release and organic cation volatilization,causing irreversible degradation of perovskite films,thereby enhancing the long-term operational stability of PSCs.Consequently,we achieve the champion inverted device with an efficiency of 24.02%.The CDs-treated PSCs exhibit high operational stability,and the maximum power point tracking only attenuates by 12.5%after 1000 h.Interfacial modification engineering supported by multifunctional quantum dots can accelerate the road to stable PSCs.展开更多
The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to...The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.展开更多
Perovskite solar cells(pero-SCs)performance is essentially limited by severe non-radiative losses and ion migration.Although numerous strategies have been proposed,challenges remain in the basic understanding of their...Perovskite solar cells(pero-SCs)performance is essentially limited by severe non-radiative losses and ion migration.Although numerous strategies have been proposed,challenges remain in the basic understanding of their origins.Here,we report a dielectric-screening-enhancement effect for perovskite defects by using organic semiconductors with finely tuned molecular structures from the atoms level.Our method produced various perovskite films with high dielectric constant values,reduced charge capture regions,suppressed ion migration,and it provides an efficient charge transport pathway for suppressing non-radiative recombination beyond the passivation effect.The resulting pero-SCs showed a promising power conversion efficiency(PCE)of 23.35%with a high open-circuit voltage(1.22 V);and the 1-cm^(2) pero-SCs maintained an excellent PCE(21.93%),showing feasibility for scalable fabrication.The robust operational and thermal stabilities revealed that this method paved a new way to understand the degradation mechanism of pero-SCs,promoting the efficiency,stability and scaled fabrication of the pero-SCs.展开更多
Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes...Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in AIGaAs nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide fitrther degrees of freedom to control the polari- zation state and the radiation diagram of the second-harmonic field.展开更多
Solution-processed metal halide perovskites (MHPs) have received significant interest for cost-effective, high-performance optoelectronic devices. In addition to the great successes in photovoltaics, their excellent l...Solution-processed metal halide perovskites (MHPs) have received significant interest for cost-effective, high-performance optoelectronic devices. In addition to the great successes in photovoltaics, their excellent luminescence and charge transport properties also make them promising for light emitting diodes (LEDs). To achieve high-efficiency perovskite LEDs (PeLEDs), extensive efforts have been carried out to enhance radiative recombination rates by confining the electrons and holes. In addition to enhancing radiative recombination rates, it is equally important to decrease the non-radiative recombination for improving the device performance. Passivation of the defects could be an efficient way for reducing the non-radiative recombination.展开更多
In today’s time each individual needs remote framework, yet at the same time control transmission for low power gadgets are wired in nature. Consistent power supply is one of the real issues in the motivation behind ...In today’s time each individual needs remote framework, yet at the same time control transmission for low power gadgets are wired in nature. Consistent power supply is one of the real issues in the motivation behind the utilization of remote sensor network. Yet, in the power arrangement of remote Sensor Network, the battery has an extremely constrained lifetime and is not supplanted yet by some other persistent power framework. There are separate techniques proposed for shorter and more separate power transmission: Inductive coupling, resonant inductive coupling and air ionization for short separations;microwave and Laser transmission for longer separations. The pioneer of the field, Tesla endeavoured to make a capable, remote electric transmitter more than a century back that has now observed an exponential development. This paper overall lights up all the effective strategies proposed for transmitting power without wires. This study is important for find out the future ways of power transmission. These methods are so important in today’s world because of drastic wastage of power. Common wireless power transmission is a point-to-point control transmission. It was demonstrated that the power transmission effectiveness could approach near 100%.展开更多
The close-to-optimal band gap,large absorption coefficient,low manufacturing cost and rapid increase in power conversion efficiency make the organic-inorganic hybrid halide（CH3NH3PbI3）and related perovskite solar ce...The close-to-optimal band gap,large absorption coefficient,low manufacturing cost and rapid increase in power conversion efficiency make the organic-inorganic hybrid halide（CH3NH3PbI3）and related perovskite solar cells very promising for commercialization.The properties of point defects in the absorber layer semiconductors have important influence on the photovoltaic performance of solar cells,so the investigation on the defect properties in the perovskite semiconductors is necessary for the optimization of their photovoltaic performance.In this work,we give a brief review to the first-principles calculation studies on the defect properties in a series of perovskite semiconductors,including the organic-inorganic hybrid perovskites and inorganic halide perovskites.Experimental identification of these point defects and characterization of their properties are called for.展开更多
Tellurite glasses with the composition of xTm2O3-(6-x)Y2O3-3Na2O-25ZnO-66TeO2(where 0≤x≤6)were obtained by the melt-quenching technique.Absorption(300 K),excitation(300 K)and fluorescence spectra(300 K)as well as fl...Tellurite glasses with the composition of xTm2O3-(6-x)Y2O3-3Na2O-25ZnO-66TeO2(where 0≤x≤6)were obtained by the melt-quenching technique.Absorption(300 K),excitation(300 K)and fluorescence spectra(300 K)as well as fluorescence decay curves of Tm^3+-doped title glasses are presented and discussed in details.The Judd-Ofelt analysis based on the room temperature absorption spectrum was applied for determination of fundamental fluorescence properties such as radiative transition probabilities(AT),branching ratios(βR),radiative lifetimes(τR)of the emitting levels of the Tm^3+ion and stimulated emission cross-sections(σem).Fluorescence spectra were recorded and analysed in the visible and near-infrared spectral range.The emission and effective cross-section were calculated for the 3F4→3H6 transition,showing that the investigated glasses are promising laser host materials,operating at 1.8μm.The observed concentration quenching and non-exponential decay curves from the 1 G4 and 3H4 states indicate nonradiative energy transfer between Tm^3+ions.The analysis of non-exponential fluorescence decay curves from the 1 G4 and 3H4 levels was carried out in framework of the InokutiHirayama and Yokota-Tanimoto models and energy transfer microparameters were determined.The self-quenching model was proposed for describing relaxation of the first excited state of the Tm^3+ion.展开更多
The potential energy surfaces for the butoxy radical dissociation into R·＋O on the six low-lying electronic states have been determined with the combined CASSCF and MR-CI methods. The isomerization reactions bet...The potential energy surfaces for the butoxy radical dissociation into R·＋O on the six low-lying electronic states have been determined with the combined CASSCF and MR-CI methods. The isomerization reactions between the different conformers of 1- and 2-butoxy radicals at the X and B states have been also investigated with the MP2, B3LYP, and CASSCF methods. The non-radiative decay mechanisms of butoxy radicals at the B state have been characterized with the computed potential energy surfaces and intersections. Supported by recent LIF experimental results, it was predicted that the t-butoxy radical would predissociate via the B/C intersection. As to 1- and 2-butoxy radicals, the relative energies of the transition states for the isomerization reactions between conformers at the B state are much lower than those of the B/C intersections, resulting in the predominance of the isomerization in the decay of the B state for 1- and 2-butoxy radicals.展开更多
Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated...Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated in detail.In this work,a series of new lipid droplets detection dyes are designed and studied,molecular optical properties and non-radiative transitions are analyzed.The intramolecular weak interaction and electron-hole analysis reveal its inner mechanisms.All dyes are proven to possess excellent photophysical properties with high fluorescence quantum efficiency and large stokes shift as well as remarkable two-photon absorption cross section.Our work reasonably elucidates the experimental measurements and the effects of substitution site on two-photon absorption and excited states properties of lipid droplets detection NAPBr dyes are highlighted,which could provide a theoretical perspective for designing efficient organic dyes for lipid droplets detection in biology and medicine fields.展开更多
Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film ...Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 21734007)Tianjin government
文摘Room temperature phosphorescence(RTP) has drawn increasing attention for its great potential in practical applications.Polymers with large molecular weights and long chains tend to form coil, which can endow them with a high degree of possible rigidity and result in the much restricted non-radiative transition. Also, the intertwined structure of polymers could isolate the oxygen and humidity effectively, thus reducing the consumption of triplet excitons. In consideration of these points, organic polymers would be another kind of ideal platform to realize RTP effect. This short review summarized the design strategy of the purely organic room temperature phosphorescence polymers, mainly focusing on the building forms of polymers and the corresponding inherent mechanisms,and also gives some outlooks on the further exploration of this field at the end of this paper.
基金supports from the National Natural Science Foundation of China(11904302,61921005)Major Project of the Science and Technology in Fujian Province of China(2019HZ020013)Major Science and Technology Projects in Xiamen of China(3502Z20191015).
文摘With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors and the number of side defects have restricted the practical applications of small sized micro-LEDs.Recently,quantum dot(QD)and nonradiative energy transfer(NRET)have been proposed to solve existing problems.QDs possess nanoscale dimensions and high luminous efficiency,and they are suitable for NRET because they are able to nearly contact the micro-LED chip.The NRET between QDs and micro-LED chip further improves the color conversion efficiency(CCE)and effective quantum yield(EQY)of full-color micro-LED devices.In this review,we discuss the NRET mechanism for QD micro-LED devices,and then nano-pillar LED,nano-hole LED,and nano-ring LED are introduced in detail.These structures are beneficial to the NRET between QD and micro-LED,especially nano-ring LED.Finally,the challenges and future envisions have also been described.
基金supported by the National Natural Science Foundation of China(U21A20331,81903743,22005322,22279151,and 22275004)National Science Fund for Distinguished Young Scholars(21925506).
文摘This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells(PSCs).Via A-site cation engineering,a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine(CMA^(+))cation,which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations,compared to the rigid phenethyl methylamine(PEA^(+))analog.It demonstrates a significantly lower non-radiative recombination rate,even though the two types of bulky cations have similar chemical passivation effects on perovskite,which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation.The resulting PSCs achieve an exceptional power conversion efficiency(PCE)of 25.5%with a record-high opencircuit voltage(V_(OC))of 1.20 V for narrow bandgap perovskite(FAPbI_(3)).The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.
基金Natural Science Foundation of Shaanxi Provincial Department of Education(20JK0486)Natural Science Foundation of Shaanxi Province(2021JQ-799)Graduate Innovation Research Project of Baoji University of Arts and Sciences(YJSCX22YB14)。
文摘In this work,cubic-phased CeO_(2):18 mol%Yb^(3+)/2 moI%Er^(3+)nanospheres were prepared by coprecipitation method,in which the size of nanosphere was precisely controlled by regulating the amount of coprecipitator urea.The morphology evolution of CeO_(2):18%Yb3+/2%Er^(3+)samples that vary from nanosphere to nano-flower with extending the reaction time was elaborately investigated via increasing the amount of urea and increasing the reaction temperature.The influence of non-radiative relaxation(NR)processes and surface quenching on up-conversion emission output of CeO_(2):18%Yb^(3+)/2%Er^(3+)was investigated through varying the sizes and environmental temperatures.Tissue imaging experiment demonstrates that CeO_(2):18%Yb^(3+)/2%Er^(3+)nanospheres have the potential to act as luminescent imaging reagents in tissue imaging.
基金acknowledge the financial supports from the Department of Science and Technology of Inner Mongolia(No.2020GG0192)the Natural Science Foundation of Inner Mongolia(No.2022ZD04)+1 种基金the Inner Mongolia Normal University(No.112/1004031962)the Inner Mongolia Autonomous Region Postgraduate Research Innovation Fund(No.S20210274Z).
文摘In recent years, with the emergence of non-fullerene fused-ring acceptors, power conversion efficiencies (PCEs) of organic solar cells (OSCs) have exceeded 19%.However, compared to inorganic or perovskite photovoltaic cells, a higher voltage loss has become one of the key factors limiting further improvement in the PCEs of OSCs.The ternary/quaternary strategy has been identified as a feasible and effective way to obtain high-efficiency OSCs.In this review, a brief outline is given of the key roles that guest materials played in reducing voltage losses in solar cell devices and a brief look at the future material design and the design of ternary/quaternary systems.
基金supported by the Japan Science and Technology Agency(JST)Mirai program(JPMJMI17EA)MEXT KAKENHI(Grant Nos.26286013,and 17H02736)。
文摘Lead chalcogenide colloidal quantum dots(CQDs)are regarded as attractive absorption materials for novel solar cells(SCs).The cost of lead chalcogenide CQD has been decreased to a commercialization target of$5/g due to the direct production of CQD inks.However,the photoelectric conversion efficiency(PCE)of lead chalcogenide CQDSCs is presently close to 14%,well below the commercialization target(20%),which is only 41%of the theoretical Shockley-Queisser limit efficiency.In this study,the different losses of open-circuit voltage(V_(oc)),fill factor(FF),and short circuit current density(J_(sc))for current CQDSCs are systematically discussed,as well as the percentage and likely causes of each loss.Then the primary reasons for the CQDSCs’performance constraints are highlighted.Following that,we focus on the CQDSCs interfaces(i.e.,CQD/CQD,CQD/HTL,and ETL/CQD)and explore viable ways to reduce device performance loss.Finally,based on the discussion above,we propose many enhancements to significantly solve numerous major obstacles impeding device performance to boost the PCE of CQDSCs for future commercialization significantly.
基金financially supported by the National Ten Thousand Talent Program for Young Top-notch Talent,China,the National Natural Science Fund for Excellent Young Scholars,China(52022030)the National Natural Science Foundation of China,China(51972111,52203330)+7 种基金the Shanghai Pilot Program for Basic Research,China(22TQ1400100-5)the “Dawn”Program of Shanghai Education Commission,China(22SG28)the Shanghai Municipal Natural Science Foundation,China(22ZR1418000)the Science and Technology Innovation Plan of Shanghai Science and Technology Commission,China(22YF1410000)the Postdoctoral Research Foundation of China,China(2021M701190)the Fundamental Research Funds for the Central Universities,China(JKD01231632,JKVD1231041)the Major Science and Technology Projects of Inner Mongolia Autonomous Region,China(2021ZD0042)the Shanghai Engineering Research Center of Hierarchical Nanomaterials,China(18DZ2252400)。
文摘Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.
基金This work was financially supported by the National Natural Science Foundation of China(51702038,U21A20331,51773212 and 81903743)the Sichuan Science&Technology Program(2020YFG0061)+1 种基金National Science Fund for Distinguished Young Scholars(21925506)Natural Science Foundation of Ningbo(2021J192).
文摘Functional additives have recently been regarded as emerging candidates to improve the performance and stability of perovskite solar cells(PSCs).Herein,nicotinamide(N),2-chloronicotinamide(2Cl),and 6-chloronicotinamide(6Cl)were employed as O-ligands to facilitate the deposition of MAPbI_(3)(MA=methylammonium)and MA-free FA_(0.88)Cs_(0.12)PbI_(2.64)Br_(0.36)(FA=formamidinium)perovskite films by multifunctional anchoring.By density functional theory(DFT)calculations and ultraviolet photoelectron spectroscopy(UPS)measurements,it is identified that the highest occupied molecular orbital(HOMO)level for additive modified MAPbI_(3)perovskite could reduce the voltage deficit for hole extraction.Moreover,due to the most favorable charge distribution and significant improvements in charge mobility and defect passivation,the power conversion efficiency(PCE)of 2Cl-MAPbI_(3)PSCs was significantly improved from 19.32%to 21.12%.More importantly,the two-dimensional grazing-incidence wide-angle X-ray scattering(GIWAXS)analysis showed that PbI_(2) defects were effectively suppressed and femtosecond transient absorption(TA)spectroscopy demonstrated that the trap-assisted recombination at grain boundaries was effectively inhibited in the 2Cl-MA-free film.As a result,the thermally stable 2Cl-MA-free PSCs achieved a remarkable PCE of 23.13%with an open-circuit voltage(V_(oc))of 1.164 V and an ultrahigh fill factor(FF)of 85.7%.Our work offers a practical strategy for further commercializing stable and efficient PSCs.
基金supported by the National Natural Science Foundation of China(52172237,22261142666)the Shaanxi International Cooperation Project(2020KWZ-018)+3 种基金the Shaanxi Science Fund for Distinguished Young Scholars(2022JC-21)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(2021-QZ-02)the Fundamental Research Funds for the Central Universities(D5000220033)the Hong Kong Scholars Program(XJ2022025)。
文摘Interfacial imperfections between the perovskite layer and the electron transport layer(ETL)in perovskite solar cells(PSCs)can lead to performance loss and negatively influence long-term operational stability.Here,we introduce an interface engineering method to modify the interface between perovskite and ETL by using multifunctional carbon dots(CDs).C=O in the CDs can chelate with the uncoordinated Pb2+in the perovskite material,inhibit interfacial recombination,and enhance the performance and stability of device.In addition,–OH in CDs forms hydrogen bonds with I-and organic cation in perovskite,inhibiting light-induced I2release and organic cation volatilization,causing irreversible degradation of perovskite films,thereby enhancing the long-term operational stability of PSCs.Consequently,we achieve the champion inverted device with an efficiency of 24.02%.The CDs-treated PSCs exhibit high operational stability,and the maximum power point tracking only attenuates by 12.5%after 1000 h.Interfacial modification engineering supported by multifunctional quantum dots can accelerate the road to stable PSCs.
基金supported by the National Natural Science Foundation of China(22275097,61875090,21772095,and 91833306)the Key Giant Project of Jiangsu Educational Committee(19KJA180005)+5 种基金the Fifth 333 Project of Jiangsu Province of China(BRA2019080)the 1311 Talents Program of Nanjing University of Posts and Telecommunicationsthe Natural Science Foundation of Jiangsu Higher Education Institutions(22KJB150030)the Scientific Starting Fund from Nanjing University of Posts and Telecommunications(NUPTSF)(NY219160)the Natural Science Foundation of Nanjing University of Posts and Telecommunications(NY221092 and NY222148)the Open Research Fund of State Key Laboratory of Organic Electronics and Information Displays。
基金supported by the National Natural Science Foundation of China(62074037,52002073)the Science and Technology Department of Fujian Province(2020I0006)+3 种基金the Natural Science Foundation of Fujian Province(2019J01218)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ124)the Education and Scientific Research Project of Fujian Province(JAT200372)the Scientific Research Project of Fujian Jiangxia University(JXZ2019006)。
文摘The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.
基金supported by the National Key Research and Development Program of China(2020YFB1506400)the National Natural Science Foundation of China(51922074,22075194,and 51820105003)+3 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJA430010)the Tang Scholarthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Collaborative Innovation Center of Suzhou Nano Science and Technology。
文摘Perovskite solar cells(pero-SCs)performance is essentially limited by severe non-radiative losses and ion migration.Although numerous strategies have been proposed,challenges remain in the basic understanding of their origins.Here,we report a dielectric-screening-enhancement effect for perovskite defects by using organic semiconductors with finely tuned molecular structures from the atoms level.Our method produced various perovskite films with high dielectric constant values,reduced charge capture regions,suppressed ion migration,and it provides an efficient charge transport pathway for suppressing non-radiative recombination beyond the passivation effect.The resulting pero-SCs showed a promising power conversion efficiency(PCE)of 23.35%with a high open-circuit voltage(1.22 V);and the 1-cm^(2) pero-SCs maintained an excellent PCE(21.93%),showing feasibility for scalable fabrication.The robust operational and thermal stabilities revealed that this method paved a new way to understand the degradation mechanism of pero-SCs,promoting the efficiency,stability and scaled fabrication of the pero-SCs.
基金Australian Research Council(ARC)Education,Audiovisual and Culture Executive Agency(EACEA)(5659/002-001)SATT IdF-Innov UniversitéSorbonne(Double Culture-PhD program)
文摘Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in AIGaAs nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide fitrther degrees of freedom to control the polari- zation state and the radiation diagram of the second-harmonic field.
文摘Solution-processed metal halide perovskites (MHPs) have received significant interest for cost-effective, high-performance optoelectronic devices. In addition to the great successes in photovoltaics, their excellent luminescence and charge transport properties also make them promising for light emitting diodes (LEDs). To achieve high-efficiency perovskite LEDs (PeLEDs), extensive efforts have been carried out to enhance radiative recombination rates by confining the electrons and holes. In addition to enhancing radiative recombination rates, it is equally important to decrease the non-radiative recombination for improving the device performance. Passivation of the defects could be an efficient way for reducing the non-radiative recombination.
文摘In today’s time each individual needs remote framework, yet at the same time control transmission for low power gadgets are wired in nature. Consistent power supply is one of the real issues in the motivation behind the utilization of remote sensor network. Yet, in the power arrangement of remote Sensor Network, the battery has an extremely constrained lifetime and is not supplanted yet by some other persistent power framework. There are separate techniques proposed for shorter and more separate power transmission: Inductive coupling, resonant inductive coupling and air ionization for short separations;microwave and Laser transmission for longer separations. The pioneer of the field, Tesla endeavoured to make a capable, remote electric transmitter more than a century back that has now observed an exponential development. This paper overall lights up all the effective strategies proposed for transmitting power without wires. This study is important for find out the future ways of power transmission. These methods are so important in today’s world because of drastic wastage of power. Common wireless power transmission is a point-to-point control transmission. It was demonstrated that the power transmission effectiveness could approach near 100%.
基金Project supported by the National Natural Science Foundation of China(No.61574059)the Shanghai Rising-Star Program(No.14QA1401500)+1 种基金the Shu-Guang Program(15SG20)the CC of ECNU
文摘The close-to-optimal band gap,large absorption coefficient,low manufacturing cost and rapid increase in power conversion efficiency make the organic-inorganic hybrid halide（CH3NH3PbI3）and related perovskite solar cells very promising for commercialization.The properties of point defects in the absorber layer semiconductors have important influence on the photovoltaic performance of solar cells,so the investigation on the defect properties in the perovskite semiconductors is necessary for the optimization of their photovoltaic performance.In this work,we give a brief review to the first-principles calculation studies on the defect properties in a series of perovskite semiconductors,including the organic-inorganic hybrid perovskites and inorganic halide perovskites.Experimental identification of these point defects and characterization of their properties are called for.
文摘Tellurite glasses with the composition of xTm2O3-(6-x)Y2O3-3Na2O-25ZnO-66TeO2(where 0≤x≤6)were obtained by the melt-quenching technique.Absorption(300 K),excitation(300 K)and fluorescence spectra(300 K)as well as fluorescence decay curves of Tm^3+-doped title glasses are presented and discussed in details.The Judd-Ofelt analysis based on the room temperature absorption spectrum was applied for determination of fundamental fluorescence properties such as radiative transition probabilities(AT),branching ratios(βR),radiative lifetimes(τR)of the emitting levels of the Tm^3+ion and stimulated emission cross-sections(σem).Fluorescence spectra were recorded and analysed in the visible and near-infrared spectral range.The emission and effective cross-section were calculated for the 3F4→3H6 transition,showing that the investigated glasses are promising laser host materials,operating at 1.8μm.The observed concentration quenching and non-exponential decay curves from the 1 G4 and 3H4 states indicate nonradiative energy transfer between Tm^3+ions.The analysis of non-exponential fluorescence decay curves from the 1 G4 and 3H4 levels was carried out in framework of the InokutiHirayama and Yokota-Tanimoto models and energy transfer microparameters were determined.The self-quenching model was proposed for describing relaxation of the first excited state of the Tm^3+ion.
基金Project supported by the National Natural Science Foundation of China （Nos. 20472011, 20673013）, the Scientific Research Foundation for the Returned 0verseas Chinese Scholars by State Education Ministry and the Major State Basic Research Development Program （No. 2004CB719903）.
文摘The potential energy surfaces for the butoxy radical dissociation into R·＋O on the six low-lying electronic states have been determined with the combined CASSCF and MR-CI methods. The isomerization reactions between the different conformers of 1- and 2-butoxy radicals at the X and B states have been also investigated with the MP2, B3LYP, and CASSCF methods. The non-radiative decay mechanisms of butoxy radicals at the B state have been characterized with the computed potential energy surfaces and intersections. Supported by recent LIF experimental results, it was predicted that the t-butoxy radical would predissociate via the B/C intersection. As to 1- and 2-butoxy radicals, the relative energies of the transition states for the isomerization reactions between conformers at the B state are much lower than those of the B/C intersections, resulting in the predominance of the isomerization in the decay of the B state for 1- and 2-butoxy radicals.
基金This work was supported by the National Natural Science Foundation of China(No.11804196 and No.11904210)the Project funded by China Postdoctoral Science Foundation(No.2018M642689)the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,(South China University of Technology)(No.2019B030301003).
文摘Two-photon fluorescence dyes have shown promising applications in biomedical imaging.However,the substitution site effect on geometric structures and photophysical properties of fluorescence dyes is rarely illustrated in detail.In this work,a series of new lipid droplets detection dyes are designed and studied,molecular optical properties and non-radiative transitions are analyzed.The intramolecular weak interaction and electron-hole analysis reveal its inner mechanisms.All dyes are proven to possess excellent photophysical properties with high fluorescence quantum efficiency and large stokes shift as well as remarkable two-photon absorption cross section.Our work reasonably elucidates the experimental measurements and the effects of substitution site on two-photon absorption and excited states properties of lipid droplets detection NAPBr dyes are highlighted,which could provide a theoretical perspective for designing efficient organic dyes for lipid droplets detection in biology and medicine fields.
基金supported by the National Natural Science Foundation of China(51903189,51800334)。
文摘Interfacial regulation,serving multiple roles,is critical for the fabrication of stable and efficient organic photovoltaics(OPVs).Herein,a multifunctional cathode interlayer PDINO(15 nm)is prepared by regulating film thickness,which is inserted between active components and stable silver electrode to align work function,and maintain good interfacial contact and device stability.The thick film can help to reduce interfacial surface defects,keep stable surface morphology,and block the silver diffusion into the active layer.Consequently,the optimal PM6:Y6 device records an impressive power conversion efficiency(PCE)of 17.48%with minimized non-radiative recombination loss of 0.239 V.More importantly,the unencapsulated device maintains 91%of the original PCE after aging for over 60 days at 25℃ and 10%relative humidity in dark conditions.Meanwhile,the PM6:eC9 device achieves a remarkable PCE of 18.22%with the enhancement of open-circuit voltage(V_(oc)).Furthermore,the 1 cm^(2) device-based PDINO(15 nm)/Ag shows a high PCE of 15.2%while only 12.6%for PDINO(9 nm)/Al,indicating the good compatibility of PDINO(15 nm)interlayer with the R2R coating processes used in large-area OPVs fabrication.This work highlights the promise of interfacial regulation to simultaneously stabilize and enhance the efficiency of organic photovoltaics.
