Band gap and molecular energy level control of perylene diimide-based donor–acceptor copolymers for all-polymer solar cells
作者:Erjun Zhou、Keisuke Tajima、Chunhe Yang、Kazuhito Hashimoto
DOI:10.1039/b923452g
日期:——
Four types of perylene diimide-based electron acceptor materials, namely, poly[9,9-dioctylfluorene-2,7-diyl-alt-N,Nâ²-di(2-ethylhexyl)-3,4,9,10-perylene diimide-1,7-diyl] (PF-PDI), poly[9,9-dioctylfluorene-2,7-diyl-alt-1,7-dithien-2-yl-N,Nâ²-di(2-ethylhexyl)-3,4,9,10-perylene diimide-5â²,5â²â²-diyl] (PF-DTPDI), polyN-[1-(2-ethylhexyl)-3-ethylheptanyl]-dithieno[3,2-b:2â²,3â²-d]pyrrole-2,6-diyl-alt-N,Nâ²-di(2-ethylhexyl)-3,4,9,10-perylene diimide-1,7-diyl} (PDTP-PDI) and polyN-[1-(2-ethylhexyl)-3-ethylheptanyl]-dithieno[3,2-b:2â²,3â²-d]pyrrole-2,6-diyl-alt-1,7-dithien-2-yl-N,Nâ²-di(2-ethylhexyl)-3,4,9,10-perylene diimide-5â²,5â²â²-diyl} (PDTP-DTPDI), have been synthesized. By changing the donor segment from fluorene to dithienopyrrole and/or introducing a thiophene unit as a spacer, the band gap and energy levels of the resulting polymers could be tuned in a wide range. PDTP-DTPDI exhibited the narrowest band gap of 1.24 eV, and the absorption edge extended to 1 μm. All-polymer solar cells based on these electron acceptors, blended with different electron donor polymers, namely, a polythiophene derivative (P1) and a low band gap polymer (P2), were also investigated. P1:PDTP-PDI blends exhibited the highest power conversion efficiency of 0.93% under the illumination of AM 1.5 (100 mW cmâ2). The monochromatic photocurrent response of the photovoltaic device based on P2:PDTP-PDI blends extended to the near-infrared region up to 1 μm.
合成了四种基于苝二酰亚胺的电子受体材料,即聚[9,9-二辛基荧光素-2,7-二基-交替-N,N′-二(2-乙基己基)-3,4,9,10-苝二酰亚胺-1,7-二基](PF-PDI)、聚[9,9-二辛基荧光素-2,7-二基-交替-1,7-二噻唑-2-基-N,N′-二(2-乙基己基)-3,4,9,10-苝二酰亚胺-5′,5′′-二基](PF-DTPDI)、聚N-[1-(2-乙基己基)-3-乙基庚烷基]-二噻吩[3,2-b:2′,3′-d]吡咯-2,6-二基-交替-N,N′-二(2-乙基己基)-3,4,9,10-苝二酰亚胺-1,7-二基}(PDTP-PDI)和聚N-[1-(2-乙基己基)-3-乙基庚烷基]-二噻吩[3,2-b:2′,3′-d]吡咯-2,6-二基-交替-1,7-二噻唑-2-基-N,N′-二(2-乙基己基)-3,4,9,10-苝二酰亚胺-5′,5′′-二基}(PDTP-DTPDI)。通过将供体段从荧光素改为二噻吩吡咯和/或引入噻吩单元作为间隔,可以在较宽范围内调节所得聚合物的带隙和能级。PDTP-DTPDI展现出最窄的带隙为1.24 eV,吸收边缘延伸至1微米。这些电子受体与不同的电子供体聚合物(即聚噻吩衍生物P1和低带隙聚合物P2)混合后,构建了全聚合物太阳能电池。基于P1:PDTP-PDI混合物的电池在AM 1.5(100 mW cm⁻²)照射下展现出最高的光电转换效率为0.93%。基于P2:PDTP-PDI混合物的光伏器件的单色光光电流响应延伸至近红外区域,达到1微米。