An “ink” solution based process, using spin-coating technique, followed by annealing in selenium environment with different temperature programs was utilized to prepare CIGSe thin films. Herein, the CuIn0.7Ga0.3Se2 nanocrystals were synthesized using ethanol — a “green” solvent. Three different solvents: 2-propanol, 2-methoxyethanol, and their 2: 1 mixture (v/v ratio), were investigated as a dispersion medium for the as-synthesized CIGSe nanocrystals to form a stable ink solution. The last one- a mixture of 2-propanol: 2-methoxyethanol=2: 1 (v/v), was found to be the most suitable. Furthermore, the influences of various annealing modes on the CIGSe grain size and density in the resulting film were also studied. The as-prepared CIGSe thin film was around 1 µm thick and possessed a tetragonal structure. A newly developed cheaper and “greener” non-vacuum process was applied successfully from the synthesis of nanocrystals to the formation of ink solution, and produced high quality thin films; this opens a new route to the cost-competitive commercialization of CIGSe thin film solar cells.

中文翻译：

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基于纳米晶体墨水的旋涂法绿色低成本制备CIGSe薄膜

基于“墨水”溶液的工艺，使用旋涂技术，然后在硒环境中以不同的温度程序退火，用于制备 CIGSe 薄膜。在此，CuIn0.7Ga0.3Se2 纳米晶体是使用乙醇（一种“绿色”溶剂）合成的。研究了三种不同的溶剂：2-丙醇、2-甲氧基乙醇及其 2:1 混合物（v/v 比）作为合成的 CIGSe 纳米晶体的分散介质，以形成稳定的墨水溶液。最后一种——2-丙醇:2-甲氧基乙醇=2:1(v/v)的混合物被发现是最合适的。此外，还研究了各种退火模式对所得薄膜中 CIGSe 晶粒尺寸和密度的影响。所制备的 CIGSe 薄膜厚度约为 1 µm，具有四方结构。从纳米晶体的合成到墨水溶液的形成，成功应用了新开发的更便宜、更“绿色”的非真空工艺，并生产出高质量的薄膜；这为 CIGSe 薄膜太阳能电池具有成本竞争力的商业化开辟了一条新途径。