Effects of donor unit and π‐bridge on photovoltaic properties of D–A copolymers based on benzo[1, 2‐b:4, 5‐c']‐dithiophene‐4, 8‐dione acceptor unit. Issue 14 (29th April 2014)

• Record Type: Journal Article
• Authors: Bin, Haijun; Xiao, Lu; Liu, Yong; Shen, Ping; Li, Yongfang
• Is Part Of: Journal of polymer science. Volume 52:Issue 14(2014:Jul.)
• Page Start: 1929
• Page End: 1940
• Publication Date: 2014-04-29
• Subjects: 547
• DOI: 10.1002/pola.27209
• Languages: English
• ISSNs: 0887-624X

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>A series of donor‐π‐acceptor (D‐π‐A) conjugated copolymers (<bold>PBDT‐AT, PDTS‐AT, PBDT‐TT</bold>, and <bold>PDTS‐TT</bold>), based on benzo[1, 2‐<italic>b</italic>:4, 5‐<italic>c</italic>']dithiophene‐4, 8‐dione (BDD) acceptor unit with benzodithiophene (BDT) or dithienosilole (DTS) as donor unit, alkylthiophene (AT) or thieno[3, 2‐<italic>b</italic>]thiophene (TT) as conjugated π‐bridge, were designed and synthesized for application as donor materials in polymer solar cells (PSCs). Effects of the donor unit and π‐bridge on the optical and electrochemical properties, hole mobilities, and photovoltaic performance of the D‐π‐A copolymers were investigated. PSCs with the polymers as donor and PC<sub>70</sub>BM as acceptor exhibit an initial power conversion efficiency (PCE) of 5.46% for <bold>PBDT‐AT</bold>, 2.62% for <bold>PDTS‐AT</bold>, 0.82% for <bold>PBDT‐TT</bold>, and 2.38% for <bold>PDTS‐TT</bold>. After methanol treatment, the PCE was increased up to 5.91%, 3.06%, 1.45%, and 2.45% for <bold>PBDT‐AT, PDTS‐AT, PBDT‐TT</bold>, and <bold>PDTS‐TT</bold>, respectively, with significantly increased FF. The effects of methanol treatment on the photovoltaic performance of the PSCs can be ascribed to the increased and balanced carrier transport and the formation of better nanoscaled interpenetrating network in the active layer. The results indicate that both donor unit and π‐bridge are crucial in designing a D‐π‐A copolymer for high‐performance photovoltaic materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. <bold>2014</bold>, <italic>52</italic>, 1929–1940</p> </abstract>