Nanostructured Si/Organic Heterojunction Solar Cells with High Open-Circuit Voltage via Improving Junction Quality

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• 作者：Shan Wu ; Wei Cui ; Nabi Aghdassi ; Tao Song ; Steffen Duhm ; Shuit-Tong Lee and Baoquan Sun
• 刊名：Advanced Functional Materials
• 出版年：2016
• 出版时间：July 25, 2016
• 年：2016
• 卷：26
• 期：28
• 页码：5035-5041
• 全文大小：894K
• ISSN：1616-3028

文摘

Nanostructured silicon (Si) can provide improved light harvest efficiencies in organic-Si heterojunction solar cells due to its low light reflection ratio compared with planar one. However, the associated large surface/volume ratio of nanostructured Si suffers from serious surface recombination as well as poor adhesion with organics in organic-Si heterojunction solar cells, which leads to an inferior open-circuit voltage (V_oc). Here, we develop a simple and effective method to suppress charge recombination as well as enhancing adhesion force between nanostructured Si and organics by incorporating a silane chemical, namely 3-glycidoxypropyltrimethoxydsilane (GOPS). GOPS can chemically graft onto nanostructured Si and improve the aqueous organic wetting properties, suppressing surface charge recombination velocity dramatically. In addition, this chemically grafted layer can enhance adhesion force between organics and Si. In such a way, a record V_oc of 640 mV associated with a power conversion efficiency of 14.1% is obtained for organic-nanostructured Si heterojunction devices. These findings suggest a promising approach to low-cost and simple fabrication for high-performance organic-Si solar cells.