Measuring the Thickness and Potential Profiles of the Space-Charge Layer at Organic/Organic Interfaces under Illumination and in the Dark by Scanning Kelvin Probe Microscopy

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• 作者：Geoffrey A. Rojas ; Yanfei Wu ; Greg Haugstad ; C. Daniel Frisbie
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 9, 2016
• 年：2016
• 卷：8
• 期：9
• 页码：5772-5776
• 全文大小：291K
• ISSN：1944-8252

文摘

Scanning Kelvin probe microscopy was used to measure band-bending at the model donor/acceptor heterojunction poly(3-hexylthiophene) (P3HT)/fullerene (C₆₀). Specifically, we measured the variation in the surface potential of C₆₀ films with increasing thicknesses grown on P3HT to produce a surface potential profile normal to the substrate both in the dark and under illumination. The results confirm a space-charge carrier region with a thickness of 10 nm, consistent with previous observations. We discuss the possibility that the domain size in bulk heterojunction organic solar cells, which is comparable to the space-charge layer thickness, is actually partly responsible for less than expected electron/hole recombination rates.