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

无机半导体纳米颗粒具有多孔表面，与块体材料相比具有极大的面积。这一特性已被应用于使用纳米多孔TiO_2的湿染料敏化太阳能电池。染料敏化太阳能电池的固化是其应用中的一个难题。TEA（Extremely Thin Absorber）型太阳能电池是一种新型的固体太阳能电池，它依赖于染料在TiO_2和p型半导体之间的p-n结处的光致电荷分离。异质结界面的复杂性决定了光伏器件的光伏特性，因此对异质结界面特性的研究具有重要意义。本文研究了由纳米多孔TiO_2/半导体聚合物异质结组成的双层器件的光伏特性。作为半导体聚合物，采用聚噻吩和聚硅烷。在周期性光照下，通过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气氛。在真空中的光照射过程中的电池的原位差谱显示了一个广泛的吸收带的增加归因于捕获的电荷载流子在近红外区域，这是开路电压的降低的起源。通过分子轨道计算、拉曼光谱和荧光光谱对载流子俘获机理进行了讨论。

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.