基于磷光材料的低给体比例有机太阳能电池

本文以低比例的磷光材料作为给体,制备了基于MoOx/C60:x%Ir(ppy)3的有机太阳能电池(OPV)器件.其中,C60为高比例的受体材料,金属配合物Ir(ppy)3为低比例的给体材料,MoOx为阳极缓冲层.通过一系列不同Ir(ppy)3比例的OPV器件对比研究,得出了最优器件结构.研究发现,当Ir(ppy)3比例足够小时,器件表现为肖特基势垒,开路电压(VOC)较大,短路电流(JSC)较小;随着Ir(ppy)3比例的增加,VOC逐渐减少,而JSC逐渐增大;当进一步增加Ir(ppy)3比例时,VOC趋于稳定,JSC开始减小.结果显示,5%Ir(ppy)3比例的器件性能最佳,效率达1.7%.为了使器件效率得到进一步提升,本研究组采用吸收光谱范围比C60更宽的C70作为受体材料,使光电转换效率进一步提升至3.0%.

Organic photovoltaic cells with small ratio of phosphorescent materials as donor component

This work employed small ratio of phosphorescent materials as donor component, and fabricated organic photovoltaic （OPV） cells with structure of MoOx/C6o：x% Ir（ppy）3. In this structure, C60 was served as high-ratio acceptor component,Ir（ppy）3 （fac-tris（2-phenylpyridine） iridium） as small-ratio donor component, and MoOx as anode buffer layer. Through fabricating OPV devices with different ratio of Ir（ppy）3, an optimal device structure was obtained. It was demonstrated that when the donor concentration was very low, Schottky barrier formed and dominated the value of device open-circuit voltage （Voc）. With increase of Ir（ppy）3 concentration, Voc dropped and the short circuit current （Jsc） increased; Voc came to stable and Jsc began to decrease as further increasing Ir（ppy）3 concentration. Device with 5% Ir（ppy）3 formed the optimal structure with power conversion efficiency （η） of 1.7%. In order to further improve 77, C70 with more intensive and wide absorption was used to replace the acceptor component of C60. As a result, dramatically improved η （3.0%） was obtained.