New Molecular Donors with Dithienopyrrole as the Electron-Donating Group for Efficient Small-Molecule Organic Solar Cells

详细信息    查看全文

• 作者：Hung-I Lu ; Chih-Wei Lu ; Ying-Chi Lee ; Hao-Wu Lin ; Li-Yen Lin ; Francis Lin ; Jung-Hung Chang ; Chih-I Wu ; Ken-Tsung Wong
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：August 12, 2014
• 年：2014
• 卷：26
• 期：15
• 页码：4361-4367
• 全文大小：432K
• ISSN：1520-5002

文摘

Six new molecules with donor鈥揳cceptor鈥揳cceptor (D鈥揂鈥揂) configuration bearing coplanar electron-donating dithieno[3,2-b:2鈥?3鈥?d]pyrrole (DTP) or aryl-substituted DTP as the D unit and the electron-withdrawing pyrimidine鈥揹icyanovinylene or benzothiadiazole鈥揹icyanovinylene as the A鈥揂 block are synthesized. The introduction of aryl groups (p-tolyl or p-anisolyl) onto the 伪 position of DTP is found to greatly benefit the chemical stability and extend the molecular conjugation of the DTP-based D鈥揂鈥揂 molecules. The observed broad absorption spectra and anisotropic molecular orientation in the thin films allow for these new D鈥揂鈥揂 molecules to perform good capability of light harvesting. These new D鈥揂鈥揂 donors are subject to the fabrication of vacuum-processed small-molecule organic solar cells (SMOSCs). The results showed that the structural modulation on the central A block (pyrimidine versus benzothiadiazole) as well as the terminal substitution (p-tolyl versus p-anisolyl) give an evident trade-off between the open circuit voltage (V_oc) and short circuit current density (J_sc) values. Among them, SMOSC-adopted D鈥揂鈥揂 molecule TDPM composed of a p-tolyl terminal group and a D鈥揂鈥揂 configuration of DTP鈥損yrimidine鈥揹icyanovinylene as the electron donor combined with C₇₀ as the electron acceptor shows a J_sc of 11.34 mA/cm², a V_oc of 0.94 V, and a fill factor (FF) of 0.52, giving a best power conversion efficiency (PCE) as high as 5.6%.