Interface-Induced Crystalline Ordering and Favorable Morphology for Efficient Annealing-Free Poly(3-hexylthiophene): Fullerene Derivative Solar Cells

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• 作者：Shuyan Shao ; Jian Liu ; Jidong Zhang ; Baohua Zhang ; Zhiyuan Xie ; Yanhou Geng ; Lixiang Wang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2012
• 出版时间：October 24, 2012
• 年：2012
• 卷：4
• 期：10
• 页码：5704-5710
• 全文大小：349K
• 年卷期：v.4,no.10(October 24, 2012)
• ISSN：1944-8252

文摘

A simple approach to fabricate high-efficiency annealing-free poly(3-hexylthiophene): [6,6]-phenyl C₆₁-butyric acid methyl ester (P3HT:PCBM) solar cells is reported by using p-type CuI to substitute PEDOT:PSS as anode buffer layer. It is found that the P3HT:PCBM blend films deposited on CuI surface show different orientation of crystalline P3HT domains and phase separation from those deposited on PEDOT:PSS surface. A nanoscale phase separation of P3HT and PCBM with domain sizes about 10鈥?0 nm is formed for the P3HT:PCBM blend films deposited on CuI surface. Absorption and grazing incidence X-ray diffraction (GIXRD) experiments indicate that the CuI layer not only induces the self-organization of P3HT chains into well-ordered structure but also results in the vertical orientation of 蟺鈥撓€ stacking planes of P3HT with respect to the substrate which is favorable for the hole collection in polymer solar cells. Hole-transport investigation discloses that hole mobility of the as-spincast P3HT:PCBM blend film on CuI surface is increased with 3 orders of magnitude compared to the P3HT:PCBM film deposited on PEDOT:PSS. A power conversion efficiency of 3.1% for the as-spincast P3HT:PCBM solar cell with CuI buffer layer is about 4-fold enhancement compared to 0.83% of the control device with PEDOT:PSS, and is comparable to the reported P3HT:PCBM solar cells subjected to post thermal treatments. This work implies that interfacial engineering is a promising approach for manipulating morphology of active layer and can potentially simplify the process and shorten the fabrication time of polymer solar cells in low-cost roll-to-roll manufacturing.

Keywords:

polymer solar cells; bulk heterojunction; chain orientation; morphology; hole transport; interface engineering