Increase in efficiency on using selenophene instead of thiophene in π-bridges for D-π-DPP-π-D organic solar cells. Issue 19 (24th April 2019)

• Record Type: Journal Article
• Authors: Cuesta, Virginia; Vartanian, Maida; Malhotra, Prateek; Biswas, Subhayan; de la Cruz, Pilar; Sharma, Ganesh D.; Langa, Fernando
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 19(2019)
• Page Start: 11886
• Page End: 11894
• Publication Date: 2019-04-24
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta02415h
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A new D–π–A–π–D system, based on selenophene and Zn-porphyrin, is described and studied as a donor in OSCs, presenting a PCE of 9.24%. Abstract : A new D–π–A–π–D small molecule (VC7 ) based on a selenophene-flanked diketopyrrolopyrrole core and two Zn-porphyrin peripheral moieties was designed and synthesized. The optical and electrochemical properties ofVC7 were investigated and compared with those ofVC6, which has the same chemical structure but with thiophene units in the π-bridge rather than selenophene.VC7 exhibited extended absorption spectra in the near infrared region of the solar spectrum and showed improved hole mobility with a high HOMO energy level. After optimization of the active layers, VC7 :PC71 BM organic solar cells (OSCs) showed a significantly higher power conversion efficiency of 9.24% ( J SC = 15.98 mA cm −2, V OC = 0.89 V and FF = 0.66) in comparison toVC6 :PC71 BM (PCE of 7.27%, J SC = 14.31 mA cm −2, V OC = 0.82 V and FF = 0.62); this result represents a 27% increase in efficiency. Our results show that the higher J SC value for theVC7 -based OSC is due to a combination of the more extended absorption profile, higher hole mobility, more balanced charge transport and high exciton dissociation probability.