The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution ro...The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution route to prepare Cu NW-based TCEs by embedding Cu NWs into pre-coated smooth poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） films on poly（ethylene terephthalate） （PET） substrates. The so obtained Cu NW- PEDOT：PSS/PET films have low surface roughness （-70 nm in height）, high stability toward oxidation and good flexibility. The optimal TCEs show a typical sheet resistance of 15Ω·sq-1 at high transparency （76% at A = 550 nm） and have been used successfully to make polymer （poly（3-hexylthiophene）：phenyl-C61- butyric acid methyl ester） solar cells, giving an efficiency of 1.4%. The overall properties of Cu NW-PEDOT：PSS/PET films demonstrate their potential application as a replacement for indium tin oxide in flexible solar cells.展开更多
Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materia...Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.展开更多
Polymer electron acceptors are the key materials in all-polymer solar cells(all-PSCs).In this review,we focused on introducing the principle of boron-nitrogen coordination bond(B←N),and summarizing our recent researc...Polymer electron acceptors are the key materials in all-polymer solar cells(all-PSCs).In this review,we focused on introducing the principle of boron-nitrogen coordination bond(B←N),and summarizing our recent research on polymer electron acceptors containing B←N unit for efficient all-PSC devices.Two approaches have been reported to design polymer electron acceptors using B←N unit.One is to replace a C-C unit by a B←N unit in conjugated polymers to transform a polymer electron donor to a polymer electron acceptor.The other approach is to construct novel electron-deficient building block based on B←N unit for polymer electron acceptors.The polymer electron acceptors containing B←N unit showed tunable lowest unoccupied molecular orbital(LUMO) energy levels and exhibited excellent all-PSC device performance with power conversion efficiency of exceeding6%.These results indicate that organic boron chemistry is a new toolbox to develop functional polymer materials for optoelectronic device applications.展开更多
Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(P...Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(PCE)of 15.49%with a short circuit current(JSC)of 24.98 mA cm^-2,an open circuit voltage(VOC)of 0.868 V and a fill factor(FF)of 71.42%.A 16.71%PCE is obtained in the optimized ternary OPVs with PBDB-T-2 Cl:Y6:PC71BM(1:1.2:0.2,wt/wt)active layer,resulting from the synchronously improved JSC of 25.44 mA cm^-2,FF of 75.66%and the constant VOCof 0.868 V.The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation,domain size and molecular arrangement in ternary active layers,which can be confirmed from the characterization on morphology,2 D grazing incidence small and wide-angle X-ray scattering,as well as Raman mapping.In addition,PC71BM may prefer to mix with Y6 to form efficient electron transport channels,which should be conducive to charge transport and collection in the optimized ternary OPVs.This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs,indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting,exciton dissociation and charge transport,while keeping the simple cell fabrication technology.展开更多
The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,ligh...The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.展开更多
Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Q...Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Queisser.However,realistic losses of the organic and perovskite PVs under indoor illumination are to be understood for further efficiency improvement.In this work,the efficiency limit of indoor PVs is calculated to 55.33%under indoor illumination(2700 K,1000 lux)when the bandgap(E_(g))of the semiconductor is 1.77 eV.The efficiency limit was obtained on the basis of assuming 100%photovoltaic external quantum efficiency(EQ_(EPV))when E≥E_(g),there was no nonradiative recombination,and there were no resistance losses.In reality,the maximum EQEPV reported in the literature is 0.80–0.90.The proportion of radiative recombination in realistic devices is only 10^(−5)–10^(−2),which causes the open-circuit voltage loss(ΔV_(loss))of 0.12–0.3 V.The fill factor(FF)of the indoor PVs is sensitive to the shunt resistance(R_(sh)).The realistic losses of EQE_(PV),nonradiative recombination,and resistance cause the large efficiency gap between the realistic values(excellent perovskite indoor PV,32.4%;superior organic indoor PV,30.2%)and the theoretical limit of 55.33%.In reality,it is feasible to reach the efficiency of 47.4%at 1.77 eV for organic and perovskite photovoltaics under indoor light(1000 lux,2700 K)with V_(OC)=1.299 V,J_(SC)=125.33μA/cm^(2),and FF=0.903 when EQE_(PV)=0.9,EQE_(EL)=10^(−1),R_(s)=0.5Ωcm^(2),and R_(sh)=10^(4) kΩcm^(2).展开更多
With the emergence of Y-series small molecule acceptors,polymerizing the small molecule acceptors with aromatic linker units has attracted significant research attention,which has greatly advanced the photovoltaic per...With the emergence of Y-series small molecule acceptors,polymerizing the small molecule acceptors with aromatic linker units has attracted significant research attention,which has greatly advanced the photovoltaic performance of all-polymer solar cells.Despite the rapid increase in efficiency,the unique characteristics(e.g.,mechanical stretchability and flexibility)of all-polymer systems were still not thoroughly explored.In this work,we demonstrate an effective approach to simultaneously improve device performance,stability,and mechanical robustness of all-polymer solar cells by properly suppressing the aggregation and crystallization behaviors of polymerized Y-series acceptors.Strikingly,when introducing 50 wt%PYF-IT(a fluorinated version of PY-IT)into the well-known PM6:PY-IT system,the all-polymer devices delivered an impressive photovoltaic efficiency of 16.6%,significantly higher than that of the control binary cell(15.0%).Compared with the two binary systems,the optimal ternary blend exhibits more efficient charge separation and balanced charge transport accompanying with less recombination.Moreover,a high-performance 1.0 cm^(2)large-area device of 15%efficiency was demonstrated for the optimized ternary all-polymer blend,which offered a desirable PCE of 14.5%on flexible substrates and improved mechanical flexibility after bending 1000 cycles.Notably,these are among the best results for 1.0 cm^(2)all-polymer OPVs thus far.This work also heralds a bright future of all-polymer systems for flexible wearable energy-harvesting applications.展开更多
Photoinduced intermolecular charge transfer(PICT)determines the voltage loss in bulk heterojunction(BHJ)organic photovoltaics(OPVs),and this voltage loss can be minimized by inducing efficient PICT,which requires ener...Photoinduced intermolecular charge transfer(PICT)determines the voltage loss in bulk heterojunction(BHJ)organic photovoltaics(OPVs),and this voltage loss can be minimized by inducing efficient PICT,which requires energy-state matching between the donor and acceptor at the BHJ interfaces.Thus,both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient PICT.In this study,an effective method for quantifying the hot state matching of OPVs was developed.The degree of energy-state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor(MF)calculated from the modified optical density of the BHJ.Furthermore,the correlation between the open-circuit voltage(Voc)of the OPV device and energy-state matching at the BHJ interface was investigated using the calculated MF.The OPVs with small absolute MF values exhibited high Voc values.This result clearly indicates that the energy-state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs.Because the MF indicates the degree of energy-state matching,which is a critical factor for suppressing energy loss,it can be used to estimate the Voc loss in OPVs.展开更多
Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with hi...Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures,thereby showing strong absorption in visible region.In this work,a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs.Copper(I)thiocyanate(CuSCN)is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility.The transparency of CuSCN benefits high average visible transmittance(AVT)of STOPVs.The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9,and the formed heterojunction exhibits an ability of exciton dissociation.High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination.The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0%with a power conversion efficiency(PCE)of 12.7%.Partial replacement of PM6 with CuSCN leads to a 63%increase in transmittance,resulting in a higher AVT of 30.9%and a comparable PCE of 10.8%.展开更多
The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior ...The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior of excitons and charge carriers within the active layer.It is also a key determinant of the photovoltaic performance of the device.During the optimization of OPV devices,the use of additives has been demonstrated to be an effective strategy in microstructure control,leading to enhanced performance.Therefore,the quest for stable and efficient novel additives,along with an exploration and summarization of the mechanisms underlying additive-induced microstructure control,is essential for a better understanding of the developmental trends of high-performance additives.In this review,we categorize additives based on their chemical structures and discuss their effects on the microstructure of the active layer from both thermodynamic and kinetic perspectives.Furthermore,we elaborate on the working mechanisms and their impact on the photovoltaic performance of the devices.This review provides an overview of recent advances in additives for OPVs,offering potential guidance for the future development of additives and further optimization of the active layer in photovoltaic devices.展开更多
Charge generation,a critical process in the operation of organic solar cell(OSC),requires thorough investigation in an ultrafast perspective.This work demonstrates that the utilization of alloy model for the non-fulle...Charge generation,a critical process in the operation of organic solar cell(OSC),requires thorough investigation in an ultrafast perspective.This work demonstrates that the utilization of alloy model for the non-fullerene acceptor(NFA)component can regulate the crystallization properties of active layer films,which in turn affects exciton diffusion and hole transfer(HT),ultimately influencing the charge generation process.By incorporating BTP-eC7 as a third component,without expanding absorption range or changing molecular energy levels but regulating the ultrafast exciton diffusion and HT processes,the power conversion efficiency(PCE)of the optimized PM6:BTP-eC9:BTP-eC7 based ternary OSC is improved from 17.30%to 17.83%,primarily due to the enhancement of short-circuit current density(JSC).Additionally,the introduction of BTP-eC7 also reduces the trap state density in the photoactive layer which helps to reduce the loss of JSC.This study introduces a novel approach for employing ternary alloy models by incorporating dual acceptors with similar structures,and elucidates the underlying mechanism of charge generation and JSC in ternary OSCs.展开更多
Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on ta...Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology,however,exhibiting limited applicability.Therefore,it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor–acceptor compatibilizers,or by introducing another third component.Herein,a unique approach is presented,based on constructing a polymer fiber rigid network with a high glass transition temperature(T_(g))to impede the movement of acceptor and donor molecules,to immobilize the active layer morphology,and thereby to improve thermal stability.A high-T_(g) one-dimensional aramid nanofiber(ANF)is utilized for network construction.Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart.The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart,thereby leaving fundamental processes such as charge separation,transport,and collection,determining the device efficiency,largely unaltered.This strategy is also successfully applied to other photovoltaic systems.The strategy of incorporating a polymer fiber rigid network with high T_(g) offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.展开更多
Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at th...Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.展开更多
文摘The easy oxidation and surface roughness of Cu nanowire （NW） films are the main bottlenecks for their usage in transparent conductive electrodes （TCEs）. Herein, we have developed a facile and scaled-up solution route to prepare Cu NW-based TCEs by embedding Cu NWs into pre-coated smooth poly（3,4-ethylenedioxythiophene）：poly（styrenesulfonate） （PEDOT：PSS） films on poly（ethylene terephthalate） （PET） substrates. The so obtained Cu NW- PEDOT：PSS/PET films have low surface roughness （-70 nm in height）, high stability toward oxidation and good flexibility. The optimal TCEs show a typical sheet resistance of 15Ω·sq-1 at high transparency （76% at A = 550 nm） and have been used successfully to make polymer （poly（3-hexylthiophene）：phenyl-C61- butyric acid methyl ester） solar cells, giving an efficiency of 1.4%. The overall properties of Cu NW-PEDOT：PSS/PET films demonstrate their potential application as a replacement for indium tin oxide in flexible solar cells.
基金Research funding from the Shanghai Municipal Education Commission in the framework of the oriental scholar and distinguished professor designationfunding from the National Natural Science Foundation of China(NSFC)
文摘Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging technologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials,conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique properties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.
基金supported by the National Key Basic Research and Development Program of China(2014CB643504,2015CB655001)the National Natural Science Foundation of China(51373165,21625403,21574129,21404099)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB12010200)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2017265)
文摘Polymer electron acceptors are the key materials in all-polymer solar cells(all-PSCs).In this review,we focused on introducing the principle of boron-nitrogen coordination bond(B←N),and summarizing our recent research on polymer electron acceptors containing B←N unit for efficient all-PSC devices.Two approaches have been reported to design polymer electron acceptors using B←N unit.One is to replace a C-C unit by a B←N unit in conjugated polymers to transform a polymer electron donor to a polymer electron acceptor.The other approach is to construct novel electron-deficient building block based on B←N unit for polymer electron acceptors.The polymer electron acceptors containing B←N unit showed tunable lowest unoccupied molecular orbital(LUMO) energy levels and exhibited excellent all-PSC device performance with power conversion efficiency of exceeding6%.These results indicate that organic boron chemistry is a new toolbox to develop functional polymer materials for optoelectronic device applications.
基金supported by the National Natural Science Foundation of China(61675017)Beijing Natural Science Foundation(4192049)
文摘Ternary organic photovoltaics(OPVs)are fabricated with PBDB-T-2 Cl:Y6(1:1.2,wt/wt)as the host system and extra PC71BM as the third component.The PBDB-T-2 Cl:Y6 based binary OPVs exhibit a power conversion efficiency(PCE)of 15.49%with a short circuit current(JSC)of 24.98 mA cm^-2,an open circuit voltage(VOC)of 0.868 V and a fill factor(FF)of 71.42%.A 16.71%PCE is obtained in the optimized ternary OPVs with PBDB-T-2 Cl:Y6:PC71BM(1:1.2:0.2,wt/wt)active layer,resulting from the synchronously improved JSC of 25.44 mA cm^-2,FF of 75.66%and the constant VOCof 0.868 V.The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation,domain size and molecular arrangement in ternary active layers,which can be confirmed from the characterization on morphology,2 D grazing incidence small and wide-angle X-ray scattering,as well as Raman mapping.In addition,PC71BM may prefer to mix with Y6 to form efficient electron transport channels,which should be conducive to charge transport and collection in the optimized ternary OPVs.This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs,indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting,exciton dissociation and charge transport,while keeping the simple cell fabrication technology.
基金Foundation of Guangzhou Science and Technology Project,Grant/Award Number:201707020019Natural Science Foundation of China,Grant/Award Numbers:21520102006,21634004。
文摘The inherent advantages of organic optoelectronic materials endow lightharvesting systems,including organic photovoltaics(OPVs)and organic photodiodes(OPDs),with multiple advantages,such as low-cost manufacturing,light weight,flexibility,and applicability to large-area fabrication,make them promising competitors with their inorganic counterparts.Among them,nearinfrared(NIR)organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry.The introduction of NIR materials into OPVs extends the absorption spectrum range,thereby enhancing the photon-harvesting ability of the devices,due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures.NIR photodiodes have tremendous potential in industrial,military,and scientific applications,such as remote control of smart electronic devices,chemical/biological sensing,environmental monitoring,optical communication,and so forth.These practical and potential applications have stimulated the development of NIR photoelectric materials,which in turn has given impetus to innovation in light-harvesting systems.In this review,we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.
基金supported by the National Natural Science Foundation of China(Nos.52273180 and 51973074)the China Postdoctoral Science Foundation(Nos.2019M662614 and 2020M682404)the WNLO Funds for Innovation.
文摘Indoor organic and perovskite photovoltaics(PVs)have been attracting great interest in recent years.The theoretical limit of indoor PVs has been calculated based on the detailed balance method developed by Shockley–Queisser.However,realistic losses of the organic and perovskite PVs under indoor illumination are to be understood for further efficiency improvement.In this work,the efficiency limit of indoor PVs is calculated to 55.33%under indoor illumination(2700 K,1000 lux)when the bandgap(E_(g))of the semiconductor is 1.77 eV.The efficiency limit was obtained on the basis of assuming 100%photovoltaic external quantum efficiency(EQ_(EPV))when E≥E_(g),there was no nonradiative recombination,and there were no resistance losses.In reality,the maximum EQEPV reported in the literature is 0.80–0.90.The proportion of radiative recombination in realistic devices is only 10^(−5)–10^(−2),which causes the open-circuit voltage loss(ΔV_(loss))of 0.12–0.3 V.The fill factor(FF)of the indoor PVs is sensitive to the shunt resistance(R_(sh)).The realistic losses of EQE_(PV),nonradiative recombination,and resistance cause the large efficiency gap between the realistic values(excellent perovskite indoor PV,32.4%;superior organic indoor PV,30.2%)and the theoretical limit of 55.33%.In reality,it is feasible to reach the efficiency of 47.4%at 1.77 eV for organic and perovskite photovoltaics under indoor light(1000 lux,2700 K)with V_(OC)=1.299 V,J_(SC)=125.33μA/cm^(2),and FF=0.903 when EQE_(PV)=0.9,EQE_(EL)=10^(−1),R_(s)=0.5Ωcm^(2),and R_(sh)=10^(4) kΩcm^(2).
基金This research was made possible thanks to the financial support of the National Natural Science Foundation of China(Nos.52073207 and 52121002)the Fundamental Research Funds for the Central Universities.L.Ye also appreciates the Peiyang Scholar Program of Tianjin University for support。
文摘With the emergence of Y-series small molecule acceptors,polymerizing the small molecule acceptors with aromatic linker units has attracted significant research attention,which has greatly advanced the photovoltaic performance of all-polymer solar cells.Despite the rapid increase in efficiency,the unique characteristics(e.g.,mechanical stretchability and flexibility)of all-polymer systems were still not thoroughly explored.In this work,we demonstrate an effective approach to simultaneously improve device performance,stability,and mechanical robustness of all-polymer solar cells by properly suppressing the aggregation and crystallization behaviors of polymerized Y-series acceptors.Strikingly,when introducing 50 wt%PYF-IT(a fluorinated version of PY-IT)into the well-known PM6:PY-IT system,the all-polymer devices delivered an impressive photovoltaic efficiency of 16.6%,significantly higher than that of the control binary cell(15.0%).Compared with the two binary systems,the optimal ternary blend exhibits more efficient charge separation and balanced charge transport accompanying with less recombination.Moreover,a high-performance 1.0 cm^(2)large-area device of 15%efficiency was demonstrated for the optimized ternary all-polymer blend,which offered a desirable PCE of 14.5%on flexible substrates and improved mechanical flexibility after bending 1000 cycles.Notably,these are among the best results for 1.0 cm^(2)all-polymer OPVs thus far.This work also heralds a bright future of all-polymer systems for flexible wearable energy-harvesting applications.
基金National Research Foundation of Korea,Grant/Award Number:2022R1A6A1A03051158BrainLink Program,Grant/Award Number:2022H1D3A3A01077343Nano Material Technology Development Program,Grant/Award Number:2021M3H4A1A02057007。
文摘Photoinduced intermolecular charge transfer(PICT)determines the voltage loss in bulk heterojunction(BHJ)organic photovoltaics(OPVs),and this voltage loss can be minimized by inducing efficient PICT,which requires energy-state matching between the donor and acceptor at the BHJ interfaces.Thus,both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient PICT.In this study,an effective method for quantifying the hot state matching of OPVs was developed.The degree of energy-state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor(MF)calculated from the modified optical density of the BHJ.Furthermore,the correlation between the open-circuit voltage(Voc)of the OPV device and energy-state matching at the BHJ interface was investigated using the calculated MF.The OPVs with small absolute MF values exhibited high Voc values.This result clearly indicates that the energy-state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs.Because the MF indicates the degree of energy-state matching,which is a critical factor for suppressing energy loss,it can be used to estimate the Voc loss in OPVs.
基金financially supported by the Sichuan Science and Technology Program (2023YFH0086, 2023YFH0085, 2023YFH0087 and 2023NSFSC0990)the State Key Laboratory of Polymer Materials Engineering (sklpme2022-3-02 and sklpme2023-2-11)the Tibet Foreign Experts Program (2022wz002)
文摘Semitransparent organic photovoltaics(STOPVs)have gained wide attention owing to their promising applications in building-integrated photovoltaics,agrivoltaics,and floating photovoltaics.Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures,thereby showing strong absorption in visible region.In this work,a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs.Copper(I)thiocyanate(CuSCN)is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility.The transparency of CuSCN benefits high average visible transmittance(AVT)of STOPVs.The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9,and the formed heterojunction exhibits an ability of exciton dissociation.High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination.The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0%with a power conversion efficiency(PCE)of 12.7%.Partial replacement of PM6 with CuSCN leads to a 63%increase in transmittance,resulting in a higher AVT of 30.9%and a comparable PCE of 10.8%.
基金supported by the National Natural Science Foundation of China(Nos.52303226,21971049)Zhejiang Provincial Natural Science Foundation(Nos.LQ23E030002,LZ23B040001)“Ten-thousand Talents Plan”of Zhejiang Province(No.2019R52040)。
文摘The microstructure of the active layer in organic photovoltaics(OPVs),such as the size of phase separation,purity of the phases,and molecular packing within each phase,plays a crucial role in influencing the behavior of excitons and charge carriers within the active layer.It is also a key determinant of the photovoltaic performance of the device.During the optimization of OPV devices,the use of additives has been demonstrated to be an effective strategy in microstructure control,leading to enhanced performance.Therefore,the quest for stable and efficient novel additives,along with an exploration and summarization of the mechanisms underlying additive-induced microstructure control,is essential for a better understanding of the developmental trends of high-performance additives.In this review,we categorize additives based on their chemical structures and discuss their effects on the microstructure of the active layer from both thermodynamic and kinetic perspectives.Furthermore,we elaborate on the working mechanisms and their impact on the photovoltaic performance of the devices.This review provides an overview of recent advances in additives for OPVs,offering potential guidance for the future development of additives and further optimization of the active layer in photovoltaic devices.
基金supported by the National Natural Science Foundation of China(52073162)Major Program of Natural Science Foundation of Shandong Province(ZR2019ZD43)+1 种基金X.T.H also acknowledges support from the Taishan Scholars Program(tstp20230610)ARC Centre of Excellence in Exciton Science(CE170100026).
文摘Charge generation,a critical process in the operation of organic solar cell(OSC),requires thorough investigation in an ultrafast perspective.This work demonstrates that the utilization of alloy model for the non-fullerene acceptor(NFA)component can regulate the crystallization properties of active layer films,which in turn affects exciton diffusion and hole transfer(HT),ultimately influencing the charge generation process.By incorporating BTP-eC7 as a third component,without expanding absorption range or changing molecular energy levels but regulating the ultrafast exciton diffusion and HT processes,the power conversion efficiency(PCE)of the optimized PM6:BTP-eC9:BTP-eC7 based ternary OSC is improved from 17.30%to 17.83%,primarily due to the enhancement of short-circuit current density(JSC).Additionally,the introduction of BTP-eC7 also reduces the trap state density in the photoactive layer which helps to reduce the loss of JSC.This study introduces a novel approach for employing ternary alloy models by incorporating dual acceptors with similar structures,and elucidates the underlying mechanism of charge generation and JSC in ternary OSCs.
基金financially supported by the Sichuan Science and Technology Program(Grant Nos.2023YFH0087,2023YFH0085,2023YFH0086,and 2023NSFSC0990)State Key Laboratory of Polymer Materials Engineering(Grant Nos.sklpme2022-3-02 and sklpme2023-2-11)+1 种基金Tibet Foreign Experts Program(Grant No.2022wz002)supported by the King Abdullah University of Science and Technology(KAUST)Office of Research Administration(ORA)under Award Nos.OSR-CARF/CCF-3079 and OSR-2021-CRG10-4701.
文摘Organic photovoltaics(OPVs)need to overcome limitations such as insufficient thermal stability to be commercialized.The reported approaches to improve stability either rely on the development of new materials or on tailoring the donor/acceptor morphology,however,exhibiting limited applicability.Therefore,it is timely to develop an easy method to enhance thermal stability without having to develop new donor/acceptor materials or donor–acceptor compatibilizers,or by introducing another third component.Herein,a unique approach is presented,based on constructing a polymer fiber rigid network with a high glass transition temperature(T_(g))to impede the movement of acceptor and donor molecules,to immobilize the active layer morphology,and thereby to improve thermal stability.A high-T_(g) one-dimensional aramid nanofiber(ANF)is utilized for network construction.Inverted OPVs with ANF network yield superior thermal stability compared to the ANF-free counterpart.The ANF network-incorporated active layer demonstrates significantly more stable morphology than the ANF-free counterpart,thereby leaving fundamental processes such as charge separation,transport,and collection,determining the device efficiency,largely unaltered.This strategy is also successfully applied to other photovoltaic systems.The strategy of incorporating a polymer fiber rigid network with high T_(g) offers a distinct perspective addressing the challenge of thermal instability with simplicity and universality.
基金financially supported by the National Natural Science Foundation of China(22173008)Beijing Key Laboratory for Chemical Power Source and Green Catalysis(2013CX02031)。
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00213920,NRF-2021R1A4A1031761).
文摘Herein,the impact of the independent control of processing additives on vertical phase separation in sequentially deposited (SD) organic photovoltaics (OPVs) and its subsequent effects on charge carrier kinetics at the electron donor-acceptor interface are investigated.The film morphology exhibits notable variations,significantly depending on the layer to which 1,8-diiodooctane (DIO) was applied.Grazing incidence wide-angle X-ray scattering analysis reveals distinctly separated donor/acceptor phases and vertical crystallinity details in SD films.Time-of-flight secondary ion mass spectrometry analysis is employed to obtain component distributions in diverse vertical phase structures of SD films depending on additive control.In addition,nanosecond transient absorption spectroscopy shows that DIO control significantly affects the dynamics of separated charges in SD films.In SD OPVs,DIO appears to act through distinct mechanisms with minimal restriction,depending on the applied layer.This study emphasizes the significance of morphological optimization in improving device performance and underscores the importance of independent additive control in the advancement of OPV technology.
