A-π-A-π-A small molecules for ternary solar cells. (May 2019)

• Record Type: Journal Article
• Authors: Zhu, Bei; Chen, Xuebin; Huang, Siyu; Peng, Xiaobin
• Is Part Of: Dyes and pigments. Volume 164(2019)
• Page Start: 148
• Page End: 155
• Publication Date: 2019-05
• Subjects: Small molecule -- A-π-A-π-A -- Photovoltaic -- Ternary solar cells; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2019.01.025
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Ternary organic solar cells (OSCs) are very promising because they can further enhance the photons' utilization efficiencies of binary cells. Herein, we design and synthesize three linear A-π-A-π-A (A: electron acceptor) small molecules (SMs) BTTR, BT2TR and BT3TR with a 2, 1, 3-benzothiadiazole (BT) unit as the central core and two 3-octylrhodanine as the end-capping units π-bridged with different numbers of thiophene units for photovoltaics. Though the binary solar cells based on PTB7/SM and SM/PC71 BM show very poor device performance with power conversion efficiencies (PCEs) < 1%, the ternary devices based on PTB7:PC71 BM with BT2TR and BT3TR as the third components exhibit PCEs of 9.30% and 9.16%, respectively, which are enhanced by >15% compared with that of the PTB7:PC71 BM binary solar cells (PCE: 7.97%). Especially, the PCEs of the ternary cells are larger than the sums of those of the two related binary solar cells, indicating that A-π-A-π-A small molecules are promising on ternary solar cells. Graphical abstract: The power conversion efficiencies of the ternary cells with two A-π-A-π-A small molecules as the third components are larger than the sums of those of the two related binary solar cells.Image 1 Highlights: A-π-A-π-A small molecules are designed and synthesized for ternary solar cells. The PCEs of the ternary cells are larger than the sums of those of the two binary ones. The π-bridges impact the electron push-pull properties and the ICT.