Significant enhancement of the photovoltaic performance of organic small molecule acceptors via side-chain engineering. Issue 17 (19th April 2018)

• Record Type: Journal Article
• Authors: Su, Wenyan; Fan, Qunping; Guo, Xia; Chen, Juan; Wang, Yan; Wang, Xiaohui; Dai, Ping; Ye, Chennan; Bao, Xiaoguang; Ma, Wei; Zhang, Maojie; Li, Yongfang
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 17(2018)
• Page Start: 7988
• Page End: 7996
• Publication Date: 2018-04-19
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta01509k
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The photovoltaic performance of PSC based onPTZ1 andIT-M is significantly improved by modulating side-chain architecture ofIT-M from para -hexylphenyl to para -hexyloxylphenyl to meta -hexyloxylphenyl and a high PCE of 11.6% has been achieved. Abstract : To achieve efficient polymer solar cells (PSCs), it is important to increase the optical absorption coefficient and charge mobility of photovoltaic materials for obtaining a high short-circuit current density ( J sc ) and fill factor (FF) in the devices without sacrificing the open-circuit voltage ( V oc ). Herein, we designed and synthesized two novel narrow bandgap n-type organic semiconductor (n-OS) acceptors namedPOIT-M andMOIT-M by modifying the side-chains ofIT-M from para -hexylphenyl to para -hexyloxylphenyl and then to meta -hexyloxylphenyl. Due to the synergistic effects of introducing oxygen atoms and varying substitution positions on the phenyl side-chains, MOIT-M shows a significantly improved absorption coefficient, stronger intermolecular π–π stacking interaction, increased crystallinity and higher electron mobility in comparison withIT-M andPOIT-M, which helps to gain higher J sc and FF in PSCs. These special features combined with the complementary absorption of theMOIT-M acceptor and wide bandgap polymerPTZ1 donor resulted in a high power conversion efficiency (PCE) of 11.6% with a V oc of 0.96 V, a J sc of 17.5 mA cm −2 and a FF of 68.8% for the PSCs processed with simple thermal annealing at 120 °C for 10 min, which is one of the highest PCEs reported for additive-free PSCs and significantly higher than those of the PSCs based onPTZ1 :IT-M (9.1%) orPTZ1 :POIT-M (9.7%). Our results indicate that side-chain engineering is an effective way to further improve the photovoltaic performance of n-OS acceptors in PSCs.