Design Considerations for Electrode Buffer Layer Materials in Polymer Solar Cells
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- 作者：David Bilby ; Bradley Frieberg ; Shobhita Kramadhati ; Peter Green ; Jinsang Kim
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：September 10, 2014
- 年：2014
- 卷：6
- 期：17
- 页码：14964-14974
- 全文大小：532K
- ISSN：1944-8252
文摘
Electrode buffer layers in polymer-based photovoltaic devices enable highly efficient devices. In the absence of buffer layers, we show that diode rectification is lost in ITO/P3HT:PCBM/Ag (ITO = indium tin oxide; P3HT = poly(3-hexylthiophene); PCBM = phenyl C61-butyric acid methyl ester) devices due to nonselective charge injection through the percolated phase pathways of a bulk heterojunction active layer. Charge-selective injection, and thus rectification and device function, can be regained by placing thin, polymeric buffer layers that break the direct electrode-active layer contact. Additionally, we show that strong active layer鈥揵uffer layer interactions lead to unwanted vertical phase separation and a kinked current鈥搗oltage curve. Device function is regained, increasing power conversion efficiency from 3.6% to 7.2%, by placing a noninteracting layer between the buffer and active layer. These results guide the design and selection of future polymeric electrode buffer layers for efficient polymer solar cell devices.