分子
接受者
有机太阳能电池
共轭体系
材料科学
结晶
聚合物
化学
小分子
“结束”组
结晶学
高分子化学
共聚物
有机化学
物理
生物化学
凝聚态物理
作者
Daehee Han,Tanya Kumari,Seungmin Jung,Yujin An,Changduk Yang
出处
期刊:Solar RRL
[Wiley]
日期:2018-03-13
卷期号:2 (5)
被引量:11
标识
DOI:10.1002/solr.201800009
摘要
Replacing hexyl‐end‐side with cyclohexyl‐end‐side groups on dithieno[3,2‐ b :2 ′ ,3 ′ ‐ d ]silole (DTSi) and dithieno[3,2‐ b :2 ′ ,3 ′ ‐ d ]germole (DTGe)‐based cores yields two new small‐molecule donors: DTSi(FBTTh 2 Cy) 2 and DTGe(FBTTh 2 Cy) 2 . Together with the hexyl‐end‐capped analogs DTSi(FBTTh 2 ) 2 and DTGe(FBTTh 2 ) 2 , the physical properties, morphology, and organic solar cell (OSC) performances with respect to hexyl‐end‐side versus cyclohexyl‐end‐side groups are investigated. The authors observe that the cyclohexyl‐end‐capped molecules show blue‐shifted film absorptions and lower exothermic crystallization temperatures due to less packed backbones compared to the hexyl‐end‐capped molecules. When used as donor materials with poly(( N,N′ ‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl)‐ alt ‐5,5 ′ ‐(2,2 ′ ‐bithiophene)) polymer acceptor, the relatively improved open‐circuit voltage is achieved from OSCs based on the hexyl‐end‐capped molecules as a result of their deeper‐lying highest occupied molecular orbitals. Nevertheless, the induced higher short‐circuit current density and fill factor parameters lead to better power conversion efficiencies in the cyclohexyl‐end‐capped molecule‐based OSCs. This is attributed to the preferential face‐on orientation with a coarsened morphology, as evidenced by a series of blend film morphological studies. The experimental findings confirm that the cyclized‐end groups in small conjugated materials possess a high potential for improving OSCs.
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