奈米顆粒敏化奈米晶體二氧化鈦之光電效應研究

Abstract

在染料敏化太陽能電池的架構中，陽極是在導電玻璃片上沈積中孔洞的二氧化鈦薄膜層組成的光電轉換工作電極。二氧化鈦的顆粒的表面吸附上染料，周圍則充滿了適當的氧化還原對電解質溶液。陰極則是另一片表面鍍上了催化用的白金顆粒的導電玻璃。利用半導體(如CdS, CdSe, CdTe等)奈米粒子作為染料比起有機的染料分子可能有著一些優勢：半導體材料比起有機分子通常含蓋更多波長的吸收範圍，同時也可能有較好的光穩定性。 我們使用了三種方法以達到以奈米粒子敏化二氧化鈦電極的目的：1. 先合成適當大小的半導體奈米粒子，再藉吸附的方式將使奈米粒子附著在二氧化鈦電極表面。2. 直接沈積在二氧電極表面就地沈積出半導體奈米粒子。3. 將合成的半導體奈米粒子與二氧化鈦粉末均勻混合後以高壓壓製出電極。以上各種方法所得的電極的皆在模擬太陽光下測試其光化學效應。

The dye-sensitized TiO2 cell consists of a light-converting anode comprising a thin film of sintered mesoporous TiO2 deposited on electrically conducting glass. The TiO2 particles are covered with sensitizing dye and surrounded by an electrolyte containing a suitable redox couple. A second piece of conducting glass coated with a catalytic amount of platinum forms the cathode. Using inorganic nanoparticles (such as CdS, CdSe, CdTe, etc.) as sensitizers implies several advantages as compared to organic dyes: Inorganic nanoparticles usually have broader absorption spectral region for light harvesting, and usually were more stable against photo-degradation. Three different approaches were used for nanoparticle sensitizing: 1. Nanoparticles were first synthesized separately with the desired size and then subsequently adsorbed them onto the TiO2 photoanode surface. 2. Nanoparticles were prepared and deposited in situ on the TiO2 photoanode in a single step. 3. Nanoparticles were first synthesized and mixed with dispersed nanocrytalline TiO2 particles, then the photoanode were fabricated using the “hydraulic pressing route”. The photoelectrochemical behaviors of these photoanodes were measured under simulated sunlight.