Enhancing the performance of CZTSSe solar cells with Ge alloying

• Published in: Solar energy materials and solar cells Vol. 105; pp. 132 - 136
• Main Authors: Guo, Qijie, Ford, Grayson M., Yang, Wei-Chang, Hages, Charles J., Hillhouse, Hugh W., Agrawal, Rakesh
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2012; Elsevier
• Subjects: Applied sciences; CZTS; CZTSSe; Direct energy conversion and energy accumulation; Earth abundant; Electrical engineering. Electrical power engineering; Electrical power engineering; Energy; Exact sciences and technology; Natural energy; Non-vacuum; Photoelectric conversion; Photovoltaic conversion; Solar cells. Photoelectrochemical cells; Solar energy; Thin film solar cell; CZTSSe; CZTS; Thin film solar cell; Non-vacuum; Earth abundant; Performance evaluation; Conversion rate; Zinc selenides; Tin sulfide; Thin film; Deposition process; Zinc sulfide; Thin film cell; Energy conversion; Copper sulfide; Non-vacuum technology; Absorbent material; Quantum yield; Solar cell; Copper selenides; Manufacturing process; Sintering; Germanium; Tin selenides; Alloying
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2012.05.039

The ability to alloy Cu2ZnSn(S,Se)4 with Ge provides a unique ability to band-gap engineer the absorber film by controlling the relative cation ratios. In here, a preliminary study on adjusting the Ge to Sn ratio is shown to significantly improve the device performance of CZTSSe thin film solar cells. CZTGeSSe solar cell with total area power conversion efficiency as high as 8.4% has been realized using a nanocrystal-based thin film deposition process. The selenized CZTGeSSe thin film exhibits a bi-layer structure where the thin sintered large-grain layer could be responsible for the poor red-response in external quantum efficiency of the resulting solar cell. [Display omitted] ► Solution synthesis of Ge alloyed CZTS nanocrystals for photovoltaic application. ► Selenization of the nanocrystal film results in CZTGeSSe thin films with a bi-layer microstructure. ► Ge alloyed CZTSSe solar cell shows enhanced open circuit voltage, fill factor, and power conversion efficiency.