An Easily Accessible Cathode Buffer Layer for Achieving Multiple High Performance Polymer Photovoltaic Cells

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• 作者：Wenchao Zhao ; Long Ye ; Shaoqing Zhang ; Huifeng Yao ; Mingliang Sun ; Jianhui Hou
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：December 10, 2015
• 年：2015
• 卷：119
• 期：49
• 页码：27322-27329
• 全文大小：536K
• ISSN：1932-7455

文摘

Here we report a successful efficiency improvement strategy in both conventional and inverted polymer solar cells (PSCs) based on multiple polymer blends, using a feasible and commercially available cathode buffer layer (CBL), namely barium hydroxide [Ba(OH)₂], to modify the photoactive blend and cathode contacts. High performance PSCs with an identical Ba(OH)₂ buffer layer were fabricated based on the multiple light-harvesting PBDT-TS1:PC₇₁BM, PffBT4T-2OD:PC₇₁BM, and PBDT-TS1:N2200 blends. The conventional PSC with Ba(OH)₂ as the CBL showed a higher power conversion efficiency (PCE) of 9.65% based on the PBDT-TS1:PC₇₁BM system under the illumination of 100 mW/cm². For the inverted cells based on the PffBT4T-2OD:PC₇₁BM system, the PCE can be improved from 4.26% (without CBL) to 9.02% after inserting the Ba(OH)₂ buffer layer. More importantly, the Ba(OH)₂ buffer layer presents similar positive effects in the conventional and inverted all-polymer devices based on a new combination, i.e., the PBDT-TS1:N2200 system. The dramatic enhancement in device performance resulted from the suitable work function of Ba(OH)₂, extremely high transmittance, and excellent film-forming capability. Therefore, inserting Ba(OH)₂ as the CBL is a simple, low-cost, and widely applicable method to simultaneously improve the conventional and inverted photovoltaic device performance.