Vacuum-Deposited Small-Molecule Organic Solar Cells with High Power Conversion Efficiencies by Judicious Molecular Design and Device Optimization

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• 作者：Yi-Hong Chen ; Li-Yen Lin ; Chih-Wei Lu ; Francis Lin ; Zheng-Yu Huang ; Hao-Wu Lin ; Po-Han Wang ; Yi-Hung Liu ; Ken-Tsung Wong ; Jianguo Wen ; Dean J. Miller ; Seth B. Darling
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：August 22, 2012
• 年：2012
• 卷：134
• 期：33
• 页码：13616-13623
• 全文大小：444K
• 年卷期：v.134,no.33(August 22, 2012)
• ISSN：1520-5126

文摘

Three new tailor-made molecules (DPDCTB, DPDCPB, and DTDCPB) were strategically designed and convergently synthesized as donor materials for small-molecule organic solar cells. These compounds possess a donor鈥揳cceptor鈥揳cceptor molecular architecture, in which various electron-donating moieties are connected to an electron-withdrawing dicyanovinylene moiety through another electron-accepting 2,1,3-benzothiadiazole block. The molecular structures and crystal packings of DTDCPB and the previously reported DTDCTB were characterized by single-crystal X-ray crystallography. Photophysical and electrochemical properties as well as energy levels of this series of donor molecules were thoroughly investigated, affording clear structure鈥損roperty relationships. By delicate manipulation of the trade-off between the photovoltage and the photocurrent via molecular structure engineering together with device optimizations, which included fine-tuning the layer thicknesses and the donor:acceptor blended ratio in the bulk heterojunction layer, vacuum-deposited hybrid planar-mixed heterojunction devices utilizing DTDCPB as the donor and C₇₀ as the acceptor showed the best performance with a power conversion efficiency (PCE) of 6.6 卤 0.2% (the highest PCE of 6.8%), along with an open-circuit voltage (V_oc) of 0.93 卤 0.02 V, a short-circuit current density (J_sc) of 13.48 卤 0.27 mA/cm², and a fill factor (FF) of 0.53 卤 0.02, under 1 sun (100 mW/cm²) AM 1.5G simulated solar illumination.