【作者】 刘军；

【导师】 刘业翔； 赖延清；

【作者基本信息】 中南大学 ， 电化学工程， 2011， 硕士

【摘要】 能源和环境的双重危机推动了世界范围内可再生能源的快速发展。太阳能作为一种清洁、安全、储量最大的可再生能源,具有其他能源无法比拟的优势；而光伏发电,作为太阳能中发展最快和最受瞩目的领域,已成为能源利用不可逆转的潮流。CuInSe2 (CIS)和Cu(In,Ga)Se2 (CIGS)薄膜具有高光吸收系数、禁带宽度与太阳光谱相匹配、电池转换效率高和稳定性好等优点,成为近些年来太阳电池材料研究的热点和重点。电沉积制备CIS和CIGS薄膜具有低成本和高效率,可大面积、连续、非真空沉积等优点,有望实现CIS和CIGS薄膜太阳电池的工业化生产,具有很好的发展前景。论文针对电沉积CIS和CIGS中存在的薄膜化学计量组成难以精确控制和沉积机理不明等主要问题,开展了下述工作：(1)对电沉积CIS和CIGS的电化学行为进行系统研究,认识了沉积机理。在电沉积过程中,硒和铜首先发生还原,生成铜硒相化合物。In以三种途径并入薄膜：In3+受硒化铜的诱导作用而发生电化学还原；In3+与H2Se反应,以硒化物的形式进入薄膜；少量的In3+可能直接还原为铟单质。而Ga则可能以两种途径并入薄膜：Ga3+与H2Se反应,以硒化物的形式进入薄膜；电极表面局部pH的升高使得Ga3+发生水解,以氧化镓的形式进入薄膜。(2)开发了新型的酸性络合剂氨基磺酸钠,并研究了其络合机制。氨基磺酸根离子能络合Cu2+和Cu+,抑制H2SeO3的还原,从而降低硒化铜的还原速率,有效抑制硒化铜二次相的过生长。通过选择合适的络合剂浓度,可以对CIGS薄膜的成分和形貌进行调控。(3)研究了电沉积主要工艺参数(沉积电位、电解质浓度、温度和pH值)对CIS和CIGS薄膜成分和形貌的影响规律。沉积电位、CuCl2和SeO2浓度显著地影响CIS和CIGS薄膜的成分和形貌。InCl3和GaCl3浓度则会影响CIGS薄膜中In和Ga的含量。高的温度不利于Cu和Se的沉积,而有利于In和Ga并入薄膜,但会带来溶液稳定性变差的问题。pH值通过影响Se的沉积,进行影响薄膜的成分和形貌。更多还原

【Abstract】 The crisis of energy and entironment promote the development of renewable energy worldwide. Comparing to other renewable resources of energy, the solar enery which is clean, safe and abundant, shows the unprecedented advantages. As the most rapidly developing field of solar energy, photovoltaic generation attracts tremendous attenttion and becomes the predominant trend in the utilization of renewable energy. CuInSe2 (CIS) and Cu(In,Ga)Se2 (CIGS) have been the research hotspots in the field of solar cells in the recent years, due to their large optical absorption coefficient, direct band-gap within the maximum solar absorption region, high efficiency and good stabilization. Currently, the electrodeposition of CIS and CIGS has been considered to be a promising approach from the viewpoint of low-cost, high-efficiency, non-vacuum, successive and large area production. The industrialization of CIS and CIGS solar cells based on electrodeposition is expected in the recent future.The electrodeposition of CIS and CIGS thin films are facing two main problems:one is that the stoichiometric composition of films are rather difficult to be controlled, the other one is that the electrodeposition mechanism is unclear. I n this work, aiming to solve these two problems, the following research works are taking:(1) The electrochemical behaviors of CuInSe2 and Cu(In,Ga)Se2 are studied systematically, and the electrodeposition mechanism is analyzed. The results reveal that Se and Cu are first reduced to from the copper selenides. The insertion of In involves three different routes:firstly, surface-induced reduction by copper selenides to form CuInSe2; secondly, reaction with H2Se to form indium selenide; thirdly, the direct reduction of In3+ to In. While the Gallium incorporates through two paths:Ga3+ reacts with H2Se to form gallium selenide; and Ga2O3 forms via Ga3+ hydrolysis from the increase of local pH. (2) Sodium sulfamate has been chosen as the new complexig agent for the acidic solution of CIS and CIGS, whose effects on the electrodeposition progress has been studied. It is found that sodium sulfamate can form complexes with Cu2+ and Cu+, and inhibit the reduction of H2Se03, therefore hinder the formation of copper selenides by reducing their reductive rate. With suitable concentration of sodium sulfamate, the composition and morphology of films can be controlled.(3) The main parameters of electrodeposition process (electrodeposition potential, reagents concentration, deposition temperature and pH) are optimized through investigating the effects of each parameter on the composition and morphology of CIS and CIGS films deposited. The electrodeposition potential, CuCl2 and SeO2 concentration markedly affects the composition and morphology of CIS and CIGS films. While InCl3 and GaCl3 concentrations just affect the deposited In and Ga levels of films. High deposition temperature is not conducive to the reduction of Cu and Se but facilitates the deposition of In and Ga. And the pH has some influence on the composition and morphology of films by affecting the reduction of Se.更多还原