Development of a New Method to Prepare Polycrystalline Silicon Thin Films for High-Efficiency and Low-Cost Solar Cells

开发一种制备高效低成本太阳能电池多晶硅薄膜的新方法

基本信息

批准号：
09480102
负责人：
NAKATO Yoshihiro
金额：
$ 7.23万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The research has been made with the aim at developing a new electrochemical method to prepare polycrystalline silicon (Si) thin films for high-efficiency and low-cost solar cells of a new type. In the new method, cheap silicon tetrachloride (SiClィイD24ィエD2), as the silicon source, was electrochemically reduced at the cathode (conductive substrate), with a molten salt used as the electrolyte. Much effort has been made to solve the problems of a very low solubility of SiClィイD24ィエD2 in the molten salt and of resulting inhomogeneous deposition of polycrystalline Si thin films. A mixed salt of aluminum trichloride and n-butylpyridinium chloride dissolved SiClィイD24ィエD2 in high concentrations, but its use was limited only below 100℃, resulting in the deposition of amorphous Si films. It was finally found that the use of a rotating cathode, only a half of it being immersed in the electrolyte, together with an eutectic melt of lithium chloride and potassium chloride as the electrolyte, gave a fairly homogeneous polycrystalline Si films. In parallel to these studies, basic studies have been made on the fabrication of a new junction appropriate for the use of polycrystalline Si films. It was found that Si-H termination bond could be converted to Si-X (X=halogen) bonds by immersin in concentrated hydrogen halide solutions containing a small amount of an oxidant, which led to shifts in the Si band edges. Interestingly, immersion of atomically flat n-Si (111) surfaces in a hydrogen iodide solution led to formation of ordered iodine nano-rods. Similar nano-rods of nickel were also formed when it was electrochemically deposited. Solid-state solar cells of a new type, "n-Si/p-CuI/ITO", gave a high open-circuit photovoltage (Voc) of 0.617 V, close to a theoretical value.

这项研究的目的是开发一种新的电化学方法，以制备多晶硅（SI）薄膜，以提高新型类型的高效和低成本太阳能电池。在新方法中，作为硅源，便宜的四氯化硅（Sicli D24）在阴极（导电底物）的电化学上降低，并用用作电解质的熔点。已经付出了很多努力来解决Sicli D24E D2在熔融盐中的非常低溶液的问题，并导致多晶Si薄膜的不均匀沉积。三氯化铝和N-叔丁基吡啶二氮的混合盐以高浓度溶解的Sicli D24E D2溶解，但其使用仅限制在100°以下，导致无定形SI膜沉积。终于发现，使用旋转阴极，其中只有一半浸入电解质中，以及氯化锂和氯化钾的共晶熔体作为电解质，产生了相当均匀的多晶Si膜。与这些研究并行，已经对适合使用多晶Si膜的新连接的制造进行了基础研究。发现Si-H终止键可以通过浸入浓缩的氢化氢溶液中，将含量少量的氧化液转化为Si-X（X =卤素）键，从而导致Si带边缘的变化。有趣的是，在碘化氢溶液中浸入原子扁平的N-Si（111）表面导致形成有序的碘纳米棒。当电化学沉积时，还形成了类似的纳米棒。新型“ N-Si/p-Cui/ITO”的固态太阳能电池的高开路光电压（VOC）为0.617 V，接近理论值。