Formation of Semiconducting Polymer/Inorganic Semiconductor Nanointerface and the Electrical and Optical Study toward ETA Solar Cell

与块体材料相比，无机半导体纳米粒子具有多孔性表面，具有极大的面积。这一特性已被应用于纳米多孔二氧化钛湿法染料敏化太阳能电池。应用中的一个问题是染料敏化太阳能电池的固化发展。TEA(Extreme Thin Absorber)型太阳电池是固体太阳电池的候选材料，它依赖于二氧化钛与p型半导体p-n结处染料的光致电荷分离。由于光伏特性严重依赖于复杂的异质结界面，因此阐明异质结界面的特性是非常重要的。本文研究了由纳米孔二氧化钛/半导体聚合物异质结组成的双层器件的光伏特性。半导体聚合物采用聚噻吩型和聚硅烷型。在周期光照射下，用光伏安法观察了其光伏特性。电池的光伏特性在很大程度上取决于测量中的大气。电池在真空中光照射时的原位差谱显示，在近红外区由于俘获电荷载流子而增加了一个宽吸收带，这是开路电压降低的原因。通过分子轨道计算、拉曼光谱和荧光光谱讨论了载流子捕获的机理。

The inorganic semiconductor nanopaticles have a porous surface with an extremely large area compared to bulk materials. The feature has been applied to a wet dye-sensitized solar cell using a nanoporous TiO_2. One of the problems in the application is the development of the solidification of the dye-sensitized solar cell. The TEA (Extremely Thin Absorber)-type solar cell is a candidate for the solid-state solar cell, which depends on the photo-induced charge separation of a dye at the p-n junction between TiO_2 and p-type semiconductor. The elucidation of the features of the heterojunction interface is important because the photovoltaic properties are seriously depends on the complicated heterojunction interface. In this study, the photovoltaic properties of a two-layer device consisting of nanoporous TiO_2/semiconducting polymer heterojunction were investigated. As semiconducting polymers, polythiophene and polysilanes were adopted. The photovoltaic properties were observed by photovoltammetry under periodic photoirradiation. The photovoltaic properties of the cell significantly depend on the atmosphere in the measurements. The in-situ difference spectra of the cell during photoirradiation in vacuo show the increase of a broad absorption band attributed to trapped charge carriers in the near-IR region, which is the origin of the decrease of the open-circuit voltage. The mechanism of the carrier trapping was discussed on the MO calculation, Raman and fluorescence spectra.