銅銦鎵硒與銅鋅錫硫薄膜太陽電池光吸收層粉體之製備與特性分析

Abstract

本研究成功使用溶熱法在240°C下製備出銅銦鎵硒(Cu(In,Ga)Se2)薄膜太陽電池光吸收層之材料，此反應僅需要5h的反應時間，可大幅降低傳統溶熱法的反應時間以及避免後續熱處理的步驟。此反應中使用了不同含量的穩定劑，並討論穩定劑對所製備之粉體其相變化、型態演變以及光致發光能量的影響，藉由適當含量之穩定劑可以成功在短時間下製備出銅銦鎵硒粉體。本研究亦由調整反應時間的變化以探討粉體在溶熱反映中的生長機制，反應的步驟和粉體型態的變化亦被提出，並觀察到粉體的型態由顆粒狀演變成片狀結構的趨勢。 本研究第二部份成功使用微波溶熱法製備出銅鋅錫硫(Cu2ZnSnS4)粉體，此方法可以在非常短的反應時間內得到kesterite和wurtzite相的粉體，此反應中Cu2S為反應中間相，藉由溶劑含量的變化以及溫度的提升，可以製備不同結構的銅鋅錫硫粉體。反應溫度以及溶劑組成所造成的相變化、結構改變、以及光致發光能量變化都在本研究中討論，並藉由調控不同的反應條件可以製備出所需結構之銅鋅錫硫粉體。

Copper indium gallium diselenide (Cu(In,Ga)Se2) particles were successfully synthesized via the solvothermal route at 240°C within only 5 h. The process considerably reduced the required reaction duration as compared with the conventionally solvothermal process via employing the capping agents. The concentrations of the stabilizer crucially influenced the phase purity, photoluminescence emission, and the microstructures of the obtained powders. The content of the stabilizer and solvent in the solution significantly affected the formation of monophasic Cu(In,Ga)Se2 powders. The reaction route and the growth process of Cu(In,Ga)Se2 prepared in the solvothermal process were proposed in this study. In the growth process of the solvothermal reaction, the particles attached mutually to form the plate-like particle via selective surface passivation of organic molecules. Cu2ZnSnS4 powders were successfully prepared via using microwave-assisted solvothermal route at 180oC within merely 1 h. Microwave irradiation acts as an efficiently heating source providing rapid heating, thereby reducing the required reaction duration for preparing monophasic Cu2ZnSnS4 powders. With adjusting the volume fraction of the solvents, single-phased kesterite and wurtzite Cu2ZnSnS4 powders were derived at 180°C and 1 h. It is proposed that the organic molecules act as a capping agent passivating the surface of the particles in the solution, leading to modifying the surface energy of crystals. The compositions of the solvent caused the microstructural evolution of the as-synthesized Cu2ZnSnS4 powders, resulting from the selective passivation in the microwave-solvothermal reaction. The photoluminescence emission of the obtained powders was influenced by the content of solvent molecules, indicating that the surface defects of particles reduced possibly. The reaction process of Cu2ZnSnS4 synthesized in the microwave-solvothermal process was proposed in this study.