A potential naphtho[2, 1-b:3, 4-b′]dithiophene-based polymer with large open circuit voltage for efficient use in organic solar cells. Issue 9 (14th January 2015)

• Record Type: Journal Article
• Authors: Kim, Yu Jin; Cheon, Ye Rim; Jang, Jae-Wan; Kim, Yun-Hi; Park, Chan Eon
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 9(2015)
• Page Start: 1904
• Page End: 1912
• Publication Date: 2015-01-14
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c4tc02597k
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : We designed a new copolymer, PNDT-BTN with NDT and alkoxy-naphthalene units. PNDT-BDT showed an effectively lowered HOMO level by inducing non-planarity, resulting in enhanced V OC . Abstract : A novel copolymer, PNDT-BTN, based on naphtho[2, 1- b :3, 4- b ′]dithiophene (NDT) and alkoxy naphthalene, was designed and synthesized by the Pd-catalyzed Stille-coupling method. The copolymer demonstrated good solubility and film-forming ability, along with good thermal stability.PNDT-BTN exhibited a broad absorption (from 300 to 600 nm), centered at 492 nm. HOMO and LUMO energy levels of the polymer were estimated to be −5.56 eV and −3.48 eV, respectively. The polymer solar cell fabricated from the blend of the polymer (donor) and PC71 BM (acceptor) exhibited a high power conversion efficiency of 4.29% with a high V OC of 0.98 V. To the best of our knowledge, this is among the highest V OC values of PSCs based on NDT derivatives. This work demonstrates that the replacement of a vinylene group in a conjugated polymer with alkoxy naphthalene moieties is able to significantly lower HOMO energy levels, and therefore, increase the open circuit voltage of solar cells.