Study of the beneficial effects of sodium doping Cu2ZnSnS4 material

This paper reports the effect of Na doping Cu2ZnSnS4 powders on the structural, morphological and optical properties. CZTS powders were synthesized by direct melting method of the constituent elements with different sodium doping concentrations from 0.5% to 2%. The resulting CZTS:Na powders were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, scanning transmission electron microscopic and UV–visible–NIR spectrophotometer. X-ray diffraction and scanning transmission electron microscopic analysis confirmed the formation of CZTS:Na with kesterite structure and preferential orientation along (112) plane. SEM results shown the microstructure with large grains with increasing the Na doping concentration. Optical measurements revealed that the band gap of CZTS decreases from 1.66 to 1.53 eV by increasing Na-doping. In addition, electrical investigations indicated that all ingots exhibit p-type conductivity. •Polycrystalline Na-doped CZTS powder was successfully obtained by direct fusion.•XRD patterns revealed that crystalline quality has been improved with Na diffusion.•CZTS:Na samples have band gap in the range 1.53–1.66 eV with p-type conductivity.