Recently,polymer solar cells developed very fast due to the application of non-fullerence acceptors.Substituting asymmetric small molecules for symmetric small molecule acceptors in the photoactive layer is a strategy...Recently,polymer solar cells developed very fast due to the application of non-fullerence acceptors.Substituting asymmetric small molecules for symmetric small molecule acceptors in the photoactive layer is a strategy to improve the performance of polymer solar cells.The asymmetric design of the molecule is very beneficial for exciton dissociation and charge transport and will also fine-tune the molecular energy level to adjust the open-circuit voltage(Voc)further.The influence on the absorption range and absorption intensity will cause the short-circuit current density(Jsc)to change,resulting in higher device performance.The effect on molecular aggregation and molecular stacking of asymmetric structures can directly change the microscopic morphology,phase separation size,and the active layer's crystallinity.Very recently,thanks to the ingenious design of active layer materials and the optimization of devices,asymmetric non-fullerene polymer solar cells(A-NF-PSCs)have achieved remarkable development.In this review,we have summarized the latest developments in asymmetric small molecule acceptors(A-NF-SMAs)with the acceptor-donor-acceptor(A-D-A)and/or acceptor-donor-acceptor-donor-acceptor(A-D-A-D-A)structures,and the advantages of asymmetric small molecules are explored from the aspects of charge transport,molecular energy level and active layer accumulation morphology.展开更多
The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist...The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist of donor and acceptor materials,indeed play important roles in OSCs,and particularly one building block has attracted considerable research attention,namely benzothiadiazole(BT).The diversity of OSCs based on the BT structure have indeed sprung up,and the progressive increase in PCE values is more than just eye-catching since it heralds a renewal and bright future of OSCs.This review analyzes significant studies that have led to these remarkable progresses and focuses on the most effective BT small-molecules and BT polymers for OSC reported in the last decades.The pivotal structure-property relationships,donor-acceptor matching criteria,and morphology control approaches are gathered and discussed in this paper.Lastly,we summarize the remaining challenges and offer a personal perspective on the future advance and improvement of OSCs.展开更多
In organic solar cells (OSCs), developing high-performing easily synthesized photoactive materials is essential for pursuing cost- effective balance. Herein, we have designed and synthesized a pair of wide-band-gap po...In organic solar cells (OSCs), developing high-performing easily synthesized photoactive materials is essential for pursuing cost- effective balance. Herein, we have designed and synthesized a pair of wide-band-gap polymers (PBDE4T-0F and PBDE4T-2F), using the low synthesis cost dicarboxylic ester-substituted quaterthiophene as the building block. Despite the minor change of molecular structure for polymer PBDE4T-xF, the fluorine substituent in polymer PBDE4T-2F greatly enhances its interchain aggregation. The higher aggregation tendency of ester-modified polymer in solution is beneficial for reducing both the aggregate size and π-π stacking distance of blend film, which contribute to the highly efficient exciton dissociation and symmetric charge transport. An impressive power-conversion efficiency (PCE) of 16.1% is achieved for the PBDE4T-2F:BTP-eC9-based device, while its counterpart only delivers a PCE of 5.8% with distinctly lower short-circuit current density (J_(sc)) and fill factor. Notably, the aggregation effect of donor polymer has also been found to be associated with the energy level shifts, and thus the variation of charge transfer energy and voltage losses for blend system. The results suggest that simultaneously reduced voltage loss and increased J_(sc) can be expected by further finely tuning the aggregation behavior of the ester-modified oligothiophene-based donor polymer.展开更多
The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we...The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co-Pi catalyst on hematite nanowire photoanode.It is found that under illumination the Co-Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co-Pi layer by increasing the electrical conductivity of the composite structure under a low potential.The Co-Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential.These results provide important new understanding of the performance improvement mechanism for the Co-Pi-modified semiconductor nanowire composite photoanodes.展开更多
Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fulleren...Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fullerene acceptor ITIC reported in 2015.The highest power conversion efficiency(PCE)is currently above 18%for OPV.However,there are still imparities in the efficiency of OPVs when compared with silicon-based photovoltaics,as well as in their shelf life.Compared with inorganicbased photovoltaics,the efficiency of large-area OPVs is lower and the life time of OPVs is shorter.Therefore,such inferior performance of large-area OPVs restricts the commercial development.Based on these constraints,this paper reviews the research work regarding OPVs into three aspects:stability,encapsulation technology,and recent large-area preparation technologies.展开更多
基金the National Key R&D Program of"Strategic Advanced Electronic Materials"(No.2016YFB0401100)the National Natural Science Foundation of China(Grant No.61574077)+1 种基金Major Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(No.19KJA460005)Natural Science Foundation of Jiangsu Province(BK20170961).
文摘Recently,polymer solar cells developed very fast due to the application of non-fullerence acceptors.Substituting asymmetric small molecules for symmetric small molecule acceptors in the photoactive layer is a strategy to improve the performance of polymer solar cells.The asymmetric design of the molecule is very beneficial for exciton dissociation and charge transport and will also fine-tune the molecular energy level to adjust the open-circuit voltage(Voc)further.The influence on the absorption range and absorption intensity will cause the short-circuit current density(Jsc)to change,resulting in higher device performance.The effect on molecular aggregation and molecular stacking of asymmetric structures can directly change the microscopic morphology,phase separation size,and the active layer's crystallinity.Very recently,thanks to the ingenious design of active layer materials and the optimization of devices,asymmetric non-fullerene polymer solar cells(A-NF-PSCs)have achieved remarkable development.In this review,we have summarized the latest developments in asymmetric small molecule acceptors(A-NF-SMAs)with the acceptor-donor-acceptor(A-D-A)and/or acceptor-donor-acceptor-donor-acceptor(A-D-A-D-A)structures,and the advantages of asymmetric small molecules are explored from the aspects of charge transport,molecular energy level and active layer accumulation morphology.
基金Major Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(No.19KJA460005)Special Science and Technology Innovation Fund of Jiangsu Province on Carbon Peak and Carbon Neutralization-Frontier Fundamental Project(No.BK20220010).
文摘The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist of donor and acceptor materials,indeed play important roles in OSCs,and particularly one building block has attracted considerable research attention,namely benzothiadiazole(BT).The diversity of OSCs based on the BT structure have indeed sprung up,and the progressive increase in PCE values is more than just eye-catching since it heralds a renewal and bright future of OSCs.This review analyzes significant studies that have led to these remarkable progresses and focuses on the most effective BT small-molecules and BT polymers for OSC reported in the last decades.The pivotal structure-property relationships,donor-acceptor matching criteria,and morphology control approaches are gathered and discussed in this paper.Lastly,we summarize the remaining challenges and offer a personal perspective on the future advance and improvement of OSCs.
基金supported by the National Natural Science Foundation of China(grant nos.51903239,21835006)S.L.also appreciates the Natural Science Foundation of Jiangsu Province(grant no.BK20221317)the startup funding from Nanjing Tech University.
文摘In organic solar cells (OSCs), developing high-performing easily synthesized photoactive materials is essential for pursuing cost- effective balance. Herein, we have designed and synthesized a pair of wide-band-gap polymers (PBDE4T-0F and PBDE4T-2F), using the low synthesis cost dicarboxylic ester-substituted quaterthiophene as the building block. Despite the minor change of molecular structure for polymer PBDE4T-xF, the fluorine substituent in polymer PBDE4T-2F greatly enhances its interchain aggregation. The higher aggregation tendency of ester-modified polymer in solution is beneficial for reducing both the aggregate size and π-π stacking distance of blend film, which contribute to the highly efficient exciton dissociation and symmetric charge transport. An impressive power-conversion efficiency (PCE) of 16.1% is achieved for the PBDE4T-2F:BTP-eC9-based device, while its counterpart only delivers a PCE of 5.8% with distinctly lower short-circuit current density (J_(sc)) and fill factor. Notably, the aggregation effect of donor polymer has also been found to be associated with the energy level shifts, and thus the variation of charge transfer energy and voltage losses for blend system. The results suggest that simultaneously reduced voltage loss and increased J_(sc) can be expected by further finely tuning the aggregation behavior of the ester-modified oligothiophene-based donor polymer.
基金financially supported by the National Natural Science Foundation of China (No.21503109)the Research-Starting Funds for Introduced Talents of Nanjing Tech University。
文摘The composite photoanodes composed by cobalt phosphate catalyst(Co-Pi) modified semiconductor have been widely used for solar water splitting,but the improvement mechanism has not been experimentally confirmed.Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co-Pi catalyst on hematite nanowire photoanode.It is found that under illumination the Co-Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co-Pi layer by increasing the electrical conductivity of the composite structure under a low potential.The Co-Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential.These results provide important new understanding of the performance improvement mechanism for the Co-Pi-modified semiconductor nanowire composite photoanodes.
基金supported by the National Key R&D Program of“Strategic Advanced Electronic Materials”(2016YFB0401100)the National Natural Science Foundation of China(61574077)+1 种基金the Major Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(19KJA460005)the Natural Science Foundation of Jiangsu Province(BK20170961)。
文摘Organic photovoltaics(OPVs)have become a timely research topic for their advantages of light weight,low cost,low toxicity,environmental adaptability,flexibility,and large-area manufacture,especially after non-fullerene acceptor ITIC reported in 2015.The highest power conversion efficiency(PCE)is currently above 18%for OPV.However,there are still imparities in the efficiency of OPVs when compared with silicon-based photovoltaics,as well as in their shelf life.Compared with inorganicbased photovoltaics,the efficiency of large-area OPVs is lower and the life time of OPVs is shorter.Therefore,such inferior performance of large-area OPVs restricts the commercial development.Based on these constraints,this paper reviews the research work regarding OPVs into three aspects:stability,encapsulation technology,and recent large-area preparation technologies.