Isomerism: Minor changes in the bromine substituent positioning lead to notable differences in photovoltaic performance

Wang，Huan1,2; Han，Liang1; Zhou，Jiadong3; Liu，Tao1; Mo，Daize1; Chen，Hui1; Lai，Haijian1; Zheng，Nan3; Xie，Zengqi3; Zheng，Wenhua2; He，Feng1,4

2021

10.31635/CCSCHEM.020.202000540

CCS Chemistry   影响因子和分区

2096-5745

2096-5745

An isomerism strategy was employed to develop single, end‐group bromine-substituted non‐fullerene two isomeric acceptors, 2,2′-((2Z,2′Z)-((12,13-bis(2-ethyl-hexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo [3,4-e]thieno[2,"3′′:4′,5′] thieno[2′,3′:4,5]pyrrolo [3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl) bis(methanylylidene))bis(4-bromo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)dimalononitrile (BTIC-2Br-β) and 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-diun-decyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno [2,"3′′:4′,5′] thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno [2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(metha-nylylidene))bis(5-bromo-3-oxo-2,3-dihydro-1Hinden-1-ylidene)dimalononitrile (BTIC-2Br-γ), for organic solar cells, aimed to examine the improvement of power conversion efficiency (PCE). The effects of isomerism on their optical, electronic, charge dynamics, morphological, and photovoltaic properties were systematically investigated. When blended with a donor poly{[4,8-bis[5-(2-ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]]} (PBDB-TF), BTIC-2Br-γ-based devices exhibited an outstanding PCE of 16.52%, they exhibited an outstanding PCE of 16.52%, which was the highest recorded value among brominated acceptors, compared with 8.11% obtained for BTIC-2Br-βbased devices. Crystallographic analysis of BTIC-2Brγ single-crystal demonstrated that the entire molecular backbone presented a plane structure between the core and end groups. Moreover, multiple intermolecular interactions such as Br⋯π and CN⋯H existing in the solid-state allowed BTIC-2Br-γ to form a three-dimensional (3D) network-packing structure, providing more electron transport channels. Our morphology investigations revealed that the BTIC-2Br-γblend films displayed tailored crystallite with distinct fibrillary nanostructures, and the low miscibility of PBDB-TF and BTIC-2Br-γ obtained by the contact angle could assist the formation of the fibrillary interpenetrating networks to achieve effective charge transport pathways. Compared with BTIC-2Br-β, BTIC-2Br-γ possessed a higher extinction coefficient, more balanced charge transport, and weaker bimolecular recombination. This work shows that subtle changes in bromine position can significantly improve the photovoltaic efficiencies of organic solar cells (OSCs); therefore, it provides a new guideline for the rational design of efficient fused-ring electron acceptors (FREAs).

3D network Bromination Fused-ring electron acceptor Isomerism Miscibility

ESCI

英语

第一 ; 通讯

National Natural Science Foundation of China[51773087,21733005,21975115] ; Shenzhen Fundamental Research Program["JCYJ20170817111214740","JCYJ20180302180238419","KQJSCX20180319114442157"] ; Shenzhen Nobel Prize Scientists Laboratory Project[C17213101] ; Guangdong Innovative and Entrepreneurial Research Team Program[2016ZT06G587]

Chemistry

Chemistry, Multidisciplinary

WOS:000794230300017

CHINESE CHEMICAL SOC

2-s2.0-85115954167

Scopus

1.Department of Chemistry,Shenzhen Grubbs Institute,Southern University of Science and Technology,Shenzhen,518055,China
2.Faculty of Health Sciences,University of Macau,999078,Macao
3.State Key Laboratory of Luminescent Materials and Devices,Institute of Polymer Optoelectronic Materials and Devices,South China University of Technology,Guangzhou,510640,China
4.Guangdong Provincial Key Laboratory of Catalysis,Southern University of Science and Technology,Shenzhen,518055,China

Wang，Huan,Han，Liang,Zhou，Jiadong,et al. Isomerism: Minor changes in the bromine substituent positioning lead to notable differences in photovoltaic performance[J]. CCS Chemistry,2021,3(9).

Wang，Huan.,Han，Liang.,Zhou，Jiadong.,Liu，Tao.,Mo，Daize.,...&He，Feng.(2021).Isomerism: Minor changes in the bromine substituent positioning lead to notable differences in photovoltaic performance.CCS Chemistry,3(9).

Wang，Huan,et al."Isomerism: Minor changes in the bromine substituent positioning lead to notable differences in photovoltaic performance".CCS Chemistry 3.9(2021).