Characteristics of In-Substituted CZTS Thin Film and Bifacial Solar Cell
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- 作者：Jie Ge ; Junhao Chu ; Jinchun Jiang ; Yanfa Yan ; Pingxiong Yang
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：December 10, 2014
- 年：2014
- 卷：6
- 期：23
- 页码：21118-21130
- 全文大小：739K
- ISSN：1944-8252
文摘
Implementing bifacial photovoltaic devices based on transparent conducting oxides (TCO) as the front and back contacts is highly appealing to improve the efficiency of kesterite solar cells. The p-type In substituted Cu2ZnSnS4 (CZTIS) thin-film solar cell absorber has been fabricated on ITO glass by sulfurizing coelectroplated Cu鈥揨n鈥揝n鈥揝 precursors in H2S (5 vol %) atmosphere at 520 掳C for 30 min. Experimental proof, including X-ray diffraction, Raman spectroscopy, UV鈥搗is鈥揘IR transmission/reflection spectra, PL spectra, and electron microscopies, is presented for the interfacial reaction between the ITO back contact and CZTS absorber. This aggressive reaction due to thermal processing contributes to substitutional diffusion of In into CZTS, formation of secondary phases and electrically conductive degradation of ITO back contact. The structural, lattice vibrational, optical absorption, and defective properties of the CZTIS alloy absorber layer have been analyzed and discussed. The new dopant In is desirably capable of improving the open circuit voltage deficit of kesterite device. However, the nonohmic back contact in the bifacial device negatively limits the open circuit voltage and fill factor, evidencing by illumination-/temperature-dependent J鈥?i>V and frequency-dependent capacitance鈥搗oltage (C鈥?i>V鈥?i>f) measurements. A 3.4% efficient solar cell is demonstrated under simultaneously bifacial illumination from both sides of TCO front and back contacts.