Tuning photovoltaic performance of DOBT-based dyes via molecular design with ethynyl-linker and terminal electron-donating segment. (May 2017)

• Record Type: Journal Article
• Authors: Wang, Lihui; Yin, Lunxiang; Wang, Lijuan; Xie, Bao; Ji, Changyan; Li, Yanqin
• Is Part Of: Dyes and pigments. Volume 140(2017)
• Page Start: 203
• Page End: 211
• Publication Date: 2017-05
• Subjects: Benzothiadiazole -- Ethynyl -- Carbazole -- Triphenylamine -- Photovoltaic performance -- Bulk heterojunction; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.01.044
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Two novel D-π-A-π-D-typed dioctyloxy-benzothiadiazole (DOBT)-based small molecules (SMs), TPAEDOBT andCZEDOBT, were designed and synthesized, consisting of ethynyl as π-linkage, besides, incorporating triphenylamine (TPA) and alkylated-carbazole (Cz) as terminal electron-donating units respectively. Single-bond compounds, TPADOBT andCZDOBT, were designed as references to fully investigate their photovoltaic (PV) performance of solution-processed devices. As expected, the PV properties were finely tuned via molecular design with ethynyl-linker and terminal electron-donating units. Among them, the best power conversion efficiency (PCE) of 3.21% was obtained forTPAEDOBT -based device due to triple-bond effect and high hole-mobility. Most importantly, a remarkably increased open-circuit voltage ( Voc ) of 1.06 V was achieved forCZEDOBT -based device due to synergistic effect of ethynyl-linker with electron-withdrawing character and Cz unit with the relatively weakened electron-donating ability, which is among the earliest report for DOBT-Cz based SMs with high V oc so far. These results provide an important guide for rational design of novel SMs PV materials. Graphical abstract: A series of novel D-π-A-π-D type DOBT-based dyes namedTPAEDOBT, CZEDOBT, TPADOBT andCZDOBT have been designed and synthesized successfully for solution-processable BHJ-OSCs. Their PV properties were finely tuned via the molecular design with ethynyl-linker and terminal electron-donating units. By contrast, the relatively high PCE of 3.21% has been achieved forTPAEDOBT -based device due to its triple-bond effect and high hole-mobility capacity. Most importantly, a remarkably increased Voc of 1.06 V has been obtained forCZEDOBT -based device due to the synergistic effect of ethynyl-linker with electron-withdrawing character and Cz units with the relatively weakened electron-donating ability, which is among the earliest report for DOBT-ethynyl-Cz based SMs with high V oc so far. The results provide the valuable hints for rational design of novel SMs-donor materials. Highlights: Four novel D-π-A-π-D-typed DOBT-based dyes have been synthesized for BHJ-OSCs. PV properties were tuned via molecular design with ethynyl-bridge and terminal D unit. A high V oc of 1.06 V was obtained forCZEDOBT due to synergistic effect of ethynyl and Cz. A best PCE was achieved forTPAEDOBT due to triple-bond and high hole-transfer capacity. The work provides valuable hints for rational design of novel SMs-donor materials.