Solution-processed bulk heterojunction solar cells based on porphyrin small molecules with very low energy losses comparable to perovskite solar cells and high quantum efficiencies. Issue 17 (1st February 2016)

• Record Type: Journal Article
• Authors: Gao, Ke; Xiao, Liangang; Kan, Yuanyuan; Yang, Binglin; Peng, Junbiao; Cao, Yong; Liu, Feng; Russell, Thomas P.; Peng, Xiaobin
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 17(2016)
• Page Start: 3843
• Page End: 3850
• Publication Date: 2016-02-01
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5tc04011f
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : The BHJ OSCs presented in this work show an energy loss of 0.53 eV but a maximum external quantum efficiency up to 61%. Abstract : Two new A–D–A conjugated small moleculesPor-Rod andPor-CNRod were developed using a porphyrin core as the donor unit and 3-ethylrhodanine and 2-(1, 1-dicyanomethylene)rhodanine as the acceptor units.Por-Rod andPor-CNRod show broad absorptions up to ∼850 nm with optical energy bandgaps of 1.47 and 1.45 eV, respectively. Additionally, their blend films containing PC71 BM show SCLC hole mobilities of 8.5 × 10 −5 and 7.5 × 10 −6 cm 2 V −1 s −1, respectively. Although bulk heterojunction solar cells containing PC71 BM that were processed either without additives, with thermal annealling alone or with only pyridine show very low power conversion efficiencies (PCEs), Por-Rod -based solar cells processed using pyridine and then thermal annealing, show a PCE of up to 4.97% with a remarkable V OC of up to 0.94 V and a very low energy loss of only 0.53 eV. This is the first report in which small molecule-based solar cells show such a low energy loss comparable to perovskite solar cells, while exhibiting a good PCE of about 5% and a maximum external quantum efficiency up to 61%. To further understand the effect of different processing conditions on the blend films, the morphology of the blend films was studied by grazing incidence X-ray diffraction and resonant soft X-ray scattering.