摘要
Three new electron donating small molecules(SMs),Pyr(EH-DPP)_2,Pyr(HD-DPP)_2 and PyrA(EH-DPP)_2,are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole(DPP) terminals,of which the derived organic solar cells(OSCs) exhibit interesting structure-performance correlation.It shows that the tune of their solubilizing side chains and π-bridge for the acceptor-donor-acceptor(A-D-A) SMs can significantly alter the resultant short-circuit current density and power conversion efficiency(PCE) in OSCs.The Pyr(EH-DPP)_2 with short side chains displays broader absorption and higher hole mobility than the Pyr(HD-DPP)_2 with long side chains.Although showing planar structure,the acetylene bridge-incorporated PyrA(EH-DPP)_2 adapts an undesired edge-on packing and strong aggregation in film,leading to non-ideal morphology and poor miscibility with fullerene acceptors.As a result,the PCE of the solar cell based on Pyr(EH-DPP)_2 is several times higher than those based on Pyr(HD-DPP)_2 and PyrA(EH-DPP)_2,indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.
Three new electron donating small molecules (SMs), Pyr(EH-DPP)2, Pyr(HD-DPP)2 and PyrA(EH-DPP)2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole (DPP) terminals, of which the derived organic solar cells (OSCs) exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor (A-D-A) SMs can significantly alter the resultant short-circuit current density and power conversion efficiency (PCE) in OSCs. The Pyr(EH-DPP)2 with short side chains displays broader absorption and higher hole mobility than the Pyr(HD-DPP)2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA(EH-DPP)2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr(EH-DPP)2 is several times higher than those based on Pyr(HD-DPP): and PyrA(EH-DPP)2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.
基金
supported by the National Natural Science Foundation of China(51473142,21674093,21374075)
the Major State Basic Research Development Program(2014CB643503)
International Science and Technology Cooperation Program of China(2016YFE0102900)