Three conjugated polymers based on thienyl-substituted benzodithiophene(BDT) and 4,7-bis-thienyl-benzothiadiazole(DTBT) with varied substitution positions of the alkyl side chains were synthesized to investigate the c...Three conjugated polymers based on thienyl-substituted benzodithiophene(BDT) and 4,7-bis-thienyl-benzothiadiazole(DTBT) with varied substitution positions of the alkyl side chains were synthesized to investigate the correlations between the structure and photovoltaic performance of the polymer photovoltaic materials.The three polymers named PBDTDTBT-p,PBDTDTBT-o and PBDTDTBT-m were characterized by a set of methods including absorption spectroscopy,cyclic voltammetry,thermogravimetric analysis,X-ray diffraction,density functional theory and photovoltaic measurements.The results show that the steric hindrance caused by the different substitution positions of the alky chains has a significant influence on the photovoltaic properties of the polymers.The open-circuit voltage(Voc) of the photovoltaic devices based on the three polymers could range from 0.67 to 0.90 V.Clearly,this finding provides us a feasible strategy to optimize the photovoltaic properties by simply changing the positions of the alkyl chains.展开更多
Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve ...Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.展开更多
Perylenediimide(PDI)-based materials exhibit great potential as non-fullerene acceptors in bulk-heterojunction(BHJ) organic solar cells(OSCs). Recent investigations have revealed that PDI molecules with a twisted stru...Perylenediimide(PDI)-based materials exhibit great potential as non-fullerene acceptors in bulk-heterojunction(BHJ) organic solar cells(OSCs). Recent investigations have revealed that PDI molecules with a twisted structure could disrupt aggregation of perylene unit. Here, we present a PDI monomer via bay-substitutions with four fused naphthalene units by three-step reactions, named TN-PDI. The introduction of four fused naphthalene rings into the bay positions of PDI unit leads to a strong steric hindrance with a twist angle of 33° between the two PDI subplanes. Blended with a wide-band gap polymer donor(PDBT-T1), the TN-PDI based non-fullerene solar cells show power conversion efficiency(PCE) of 3.0%. Our results indicate that the bay-substitutions with fused aromatic substitutions could be an efficient approach to develop monomeric PDI acceptors.展开更多
基金supported by the National Basic Research Program(2014CB643500)the National Natural Science Foundation of China(91333204 and 51261160496)the Chinese Academy of Sciences(XDB12030200 and KJZDEW-J01)
文摘Three conjugated polymers based on thienyl-substituted benzodithiophene(BDT) and 4,7-bis-thienyl-benzothiadiazole(DTBT) with varied substitution positions of the alkyl side chains were synthesized to investigate the correlations between the structure and photovoltaic performance of the polymer photovoltaic materials.The three polymers named PBDTDTBT-p,PBDTDTBT-o and PBDTDTBT-m were characterized by a set of methods including absorption spectroscopy,cyclic voltammetry,thermogravimetric analysis,X-ray diffraction,density functional theory and photovoltaic measurements.The results show that the steric hindrance caused by the different substitution positions of the alky chains has a significant influence on the photovoltaic properties of the polymers.The open-circuit voltage(Voc) of the photovoltaic devices based on the three polymers could range from 0.67 to 0.90 V.Clearly,this finding provides us a feasible strategy to optimize the photovoltaic properties by simply changing the positions of the alkyl chains.
基金the Ministry of Science and Technology of China(2017YFA0204504)the National Natural Science Foundation of China(51873221,52073292,51673207,21774003,and 51373183)+2 种基金Chinese Academy of Sciences and Dutch Research Project(1A111KYSB20190072)Beijing Municipal Science&Technology Commission(Z181100004418012)Beijing Natural Science Foundation(2212032).
文摘Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.
基金supported by the National Natural Science Foundation of China(51473009 and 51273203)the Fundamental Research Funds for the Central Universities(YWF-14-HHXY-007and YWF-14-HXXY-014)
文摘Perylenediimide(PDI)-based materials exhibit great potential as non-fullerene acceptors in bulk-heterojunction(BHJ) organic solar cells(OSCs). Recent investigations have revealed that PDI molecules with a twisted structure could disrupt aggregation of perylene unit. Here, we present a PDI monomer via bay-substitutions with four fused naphthalene units by three-step reactions, named TN-PDI. The introduction of four fused naphthalene rings into the bay positions of PDI unit leads to a strong steric hindrance with a twist angle of 33° between the two PDI subplanes. Blended with a wide-band gap polymer donor(PDBT-T1), the TN-PDI based non-fullerene solar cells show power conversion efficiency(PCE) of 3.0%. Our results indicate that the bay-substitutions with fused aromatic substitutions could be an efficient approach to develop monomeric PDI acceptors.
