太陽電池吸收層材料之銅銦硒粉體製備與特性分析

Abstract

本研究成功利用微波溶熱法於200度時合成銅銦硒(CuInSe2)之薄膜太陽能電池吸收層材料，藉由此方法可在非常短的時間內得到單相銅銦硒粉體。此結果是由於在微波電場(microwave field)的作用下，反應物的移動率(mobility)會提高，因此會使得反應速率提升。在此研究中，硒化銅(CuSe)為反應的中間產物，且當反應溫度提升時，銅銦硒的相會逐漸顯現。藉由微波溶熱法所製備的樣品型態為片狀和球狀粉體，且片狀粉體的比例會隨著反應溫度上升而提高。從這部分研究中可發現，將溶熱法和微波加熱系統結合，可大幅促進片狀粉體的生成。 本研究第二部分使用微乳膠溶熱法合成銅銦硒粉體。微乳膠系統中形成的微胞可視為個別的奈米級反應器，可以限制銅銦硒粉體的生長。由於反應物間的距離被拉近，使得反應速率增加，因此縮短了合成所需的時間。一般微乳膠製程，需要在400至500oC排膠，在本研究結合了溶熱法，使得反應所需溫度可大幅降至200oC。由微乳膠溶熱法所製備的粉體呈現圓形粒子，且和傳統溶熱法相比，粉體粒徑變小很多，大約10-15奈米。也發現當反應溫度提高時，樣品晶相及粉體大小也都會提高。

Copper indium diselenide (CuInSe2) powders were successfully synthesized using the microwave-assisted solvothermal process at 200oC within short time. The reaction time for preparing single-phased CuInSe2 was significantly shortened with the developed microwave treatment. The microwave field enhanced the mobility of the reactants, thereby resulting in the accelerated reaction rate. CuSe was the major intermediate product during reactions, and the phase of CuInSe2 was gradually formed as the reaction temperature and time were raised. The prepared powders exhibited plate-like and spherical shapes, and the fraction of plate was increased with increasing reaction time. The solvothermal route combined with the microwave heating system was found to significantly promote the formation of plate-like particles. CuInSe2 powders were successfully prepared using the water-in-oil microemulsion-mediated solvothermal process. The formed micelles in the water-in-oil microemulsion system acted as nanosized reactors to restrict the growth of CuInSe2 powders. The distances between the constituent reactants were shortened, thereby leading to raise the reaction rate and shorten the required reaction time. In the microemulsion process, the obtained powders must be heated to 400 – 500oC for removing the residual organics. The reaction temperature was significantly lowered to 200oC with the assistance of the solvothermal treatment. The microemulsion-derived CuInSe2 powders exhibited a spherical shape and were much smaller than the powders prepared via the conventional solvothermal process. The particle sizes of the obtained powders were around 10–15 nm. As the reaction temperature was elevated, the crystallinity and the particle size were also increased.