Single-bond-linked oligomeric donors for high performance organic solar cells  

作　　者：Min Lv Yi Tang Dingding Qiu Wenjun Zou Ruimin Zhou Lixuan Liu Ziyun Huang Jianqi Zhang Kun Lu Zhixiang Wei 

机构地区：[1]CAS Key Laboratory of Nanosystem and Hierarchical Fabrication,CAS Center for Excellence in Nanoscience,National Center for Nanoscience and Technology,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Chemical Letters》2023年第2期604-609,共6页中国化学快报（英文版）

基　　金：financial support provided by the National Natural Science Foundation of China (Nos. 21822503 and 51973043);the Youth Innovation Promotion Association, the Chinese Academy of Sciences (No. GJHZ2092-019)。

摘　　要：The effective design and synthesis of novel small-molecule donors(SMDs) is extremely essential for the in-depth study of the scientific problems of bulk heterojunction morphology and the improvement of photovoltaic performance in organic solar cells(OSCs). Importantly, developing a series of donors with different conjugated central donor(D) units is a remarkable strategy to obtain high-performance donors. Herein, two acceptor-donor-donor-acceptor(A-D-D-A) type oligomeric donors 2DTBDT and2DTBDT-2T with two dithieno[2,3-d:2,3-d’]benzo[1,2-b:4,5-b’]dithiophene(DTBDT) as D units, without and with bithiophene as the π bridge respectively are designed and synthesized successfully. The central linked-DTBDT unit can provide a larger conjugated plane and promote π electron delocalization, which can effectively improve π-π interactions between donors and regulate the crystallinity. And we found that the π bridge provided 2DTBDT-2T with 12.31% efficiency that is already a high efficiency in OSCs,whereas 2DTBDT with merely 3.63% efficiency, both with 2,2-((2Z,2 Z)-((12,13-bis(2-ethylhexyl)-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,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)) dimalononitrile(Y6) as the acceptor. We conjecture that the main reason for the different device performance may be ascribed to the different molecular stacking orientation of the oligomeric donors and morphology features of the donors:Y6 blend films. Compared to the predominant face-on orientation of the 2DTBDT neat film, the 2DTBDT-2T neat film performed a preferential edge-on orientation, which obtained a smoother surface, stronger crystallinity and more uniform phase separation in the 2DTBDT-2T:Y6 blend films with nanofiber structure, which delivered higher and more balanced carrier mobilities, the more efficient exciton dissociation and reduced biomolecule recombination, therefore obtaining better

关 键 词：Linked donor Oligomeric donors Molecular stacking orientation Organic solar cells 

分 类 号：TM914.4[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]