High-voltage organic solar cells(OSCs)have received increasing attention because of their promising applications in tandem devices and indoor photovoltaics,but the trade-off between energy loss and charge generation i...High-voltage organic solar cells(OSCs)have received increasing attention because of their promising applications in tandem devices and indoor photovoltaics,but the trade-off between energy loss and charge generation induced by exciton binding energy(E_(b))has become one of the biggest bottlenecks limiting the development of this field.Here,a wide bandgap(WBG)nonfullerene acceptor BTA503 with reduced E_(b) is designed by changing the phenyl side chain on the central core of Cl-BTA5 to an alkyl chain.The diverseπ-πinteractions and enhanced molecular stacking of BTA503 are responsible for its reduced E_(b).Furthermore,both the diminished charge recombination and the fast exciton dissociation caused by the small E_(b) favor the generation of more charge carriers for the PTQ10:BTA503 combination.The efficient Forster resonance energy transfer(FRET)and multiple π-π stacking patterns provide additional charge transfer and transport pathways.Ultimately,the PTQ10:BTA503-based OSC device achieves a V_(OC)of 1.112 V and a PCE of 12.70%,which is higher than that of PTQ10:Cl-BTA5(PCE=10.92%).Simultaneously,the thick film(~300 nm)binary device of PTQ10:BTA503 achieves a PCE of 10.13% with a V_(OC)of 1.102 V,which is the best result for thick film high-voltage OSCs.More importantly,the ternary device of PTQ10:BTA503:Cl-BTA5(1:0.9:0.1)realizes a champion PCE of 13.12% with a V_(OC)of 1.126 V.Our study demonstrates that it is an effective strategy to reduce E_(b) of A_(2)-A_(1)-D-A_(1)-A_(2) type WBG acceptors by modulating the side chains on D unit,which further favors the corresponding devices to obtain world-record PCE and improves their potential for commercial applications.展开更多
基金supported by the National Natural Science Foundation of China(21875052,51873044)。
文摘High-voltage organic solar cells(OSCs)have received increasing attention because of their promising applications in tandem devices and indoor photovoltaics,but the trade-off between energy loss and charge generation induced by exciton binding energy(E_(b))has become one of the biggest bottlenecks limiting the development of this field.Here,a wide bandgap(WBG)nonfullerene acceptor BTA503 with reduced E_(b) is designed by changing the phenyl side chain on the central core of Cl-BTA5 to an alkyl chain.The diverseπ-πinteractions and enhanced molecular stacking of BTA503 are responsible for its reduced E_(b).Furthermore,both the diminished charge recombination and the fast exciton dissociation caused by the small E_(b) favor the generation of more charge carriers for the PTQ10:BTA503 combination.The efficient Forster resonance energy transfer(FRET)and multiple π-π stacking patterns provide additional charge transfer and transport pathways.Ultimately,the PTQ10:BTA503-based OSC device achieves a V_(OC)of 1.112 V and a PCE of 12.70%,which is higher than that of PTQ10:Cl-BTA5(PCE=10.92%).Simultaneously,the thick film(~300 nm)binary device of PTQ10:BTA503 achieves a PCE of 10.13% with a V_(OC)of 1.102 V,which is the best result for thick film high-voltage OSCs.More importantly,the ternary device of PTQ10:BTA503:Cl-BTA5(1:0.9:0.1)realizes a champion PCE of 13.12% with a V_(OC)of 1.126 V.Our study demonstrates that it is an effective strategy to reduce E_(b) of A_(2)-A_(1)-D-A_(1)-A_(2) type WBG acceptors by modulating the side chains on D unit,which further favors the corresponding devices to obtain world-record PCE and improves their potential for commercial applications.
