Easy and low-cost aqueous precipitation method to obtain Cu2ZnSn(S, Se)4 thin layers

- CZTSSe absorber structure was obtained using Doctor Blade deposition of metallic precursors prepared by aqueous, low cost co-precipitation route.
- Kesterite solar cell was fabricated using the CZTSSe films.
- Efficiency of 4.9%, VOC of 532 mV, JSC of 21,5 mA/cm2 and FF of 42,8% were achieved.

An easy method to obtain kesterite Cu2ZnSn(Se1−x,Sx)4 (CZTSSe) thin films as absorbers for photovoltaic solar cells is discussed in this report. Particular emphasis is directed towards preparation steps of CZTSSe, as well as its crystal structure and properties. The CZTSSe has been developed by a low-cost and sustainable aqueous precipitation method that included metal selenite´s precipitation, its reduction to metal selenides and further crystallization of kesterite. The use of an aqueous solution instead of organic compounds and sulfurization process at atmospheric conditions makes this process attractive for large-scale industrial fabrication of CZTSSe thin film solar cells.The kesterite CZTSSe solid solution has been characterized in terms of its chemical composition, structural and morphological transformations and optical and electrical properties, confirming the viability and effectiveness of the applied process. The optimal electrical parameters were found to be: 21.5 mA/cm2 short circuit current (Jsc), 532 mV open circuit voltage (Voc), 42.8% fill factor (FF) and total area efficiency of 4.9% (Eff) without antireflection coating.

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