Charge transfer and recombination in organic/inorganic hybrid composites with CuInS₂ nanocrystals studied by light-induced electron spin resonance

详细信息    查看全文

• 作者：Christopher Krause^a ; ^{christopher.krause@uni-oldenburg.de" class="auth_mail} ; Rany Miranti^a ; Florian Witt^a ; Johannes Neumann^b ; Daniela Fenske^b ; Jü ; rgen Parisi^a ; Holger Borchert^a
• 关键词：Charge transfer ; Electron spin resonance ; CuInS2 nanoparticle ; Hybrid solar cells ; Ligand exchange
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：May, 2014
• 年：2014
• 卷：124
• 期：Complete
• 页码：241-246
• 全文大小：1152 K

文摘

Charge separation is an important elementary step in solar cells with donor/acceptor heterojunctions. In this work, light-induced electron spin resonance (LESR) is used to study the charge transfer and recombination of photo-generated charge carriers in inorganic/organic hybrid composites of CuInS₂ nanoparticles with the conjugated polymer poly(3-hexylthiophene) (P3HT) or the electron acceptor phenyl-C₆₁-butyric acid methyl ester (PCBM), respectively. After synthesis, the CuInS₂ nanoparticles are surrounded by a ligand shell composed of relatively long-chained organic molecules. A ligand shell modification with hexanethiol was applied to the CuInS₂ nanoparticles to study the influence of the ligand shell on the charge separation process. The effect of the hexanethiol treatment on the initial ligand shell present after synthesis was analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). We demonstrate that charge transfer in both the CuInS₂/P3HT and CuInS₂/PCBM composites is possible and in case of P3HT strongly influenced by the ligand shell. The recombination kinetics of photo-generated charge carriers reveals that trapping is especially governed by the organic semiconductor. Laboratory solar cells with CuInS₂/P3HT or CuInS₂/PCBM as the photoactive layer are presented as well.