Effects of K ions doping on the structure, morphology and optical properties of Cu2FeSnS4 thin films prepared by blade-coating process

Abstract:

Quaternary chalcogenide Cu2FeSnS4 (CFTS) nanoparticles, as a kind of potential absorber layer material in thin film solar cells (TFSCs), were successfully synthesized by using a convenient solvothermal method. Alkali element K is incorporated into CFTS thin films in order to further improve the surface morphology and the optical properties of related films. X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM) were used to characterize the phase purity, morphology and composition of CFTS particles and thin films. The results show that the particle elemental ratios of Cu/(Fe+Sn) and Fe/Sn are 1.2 and 0.9, respectively, which are close to the characteristics of stoichiometric CFTS. The band gaps of CFTS films before and after doping K ions are estimated to be 1.44 eV and 1.4 eV with an error of ±0.02 eV. This work has been supported by National Natural Science Foundation of China (No. 51674026), and the Fundamental Research Funds for the Central Universities in 2015 (No.FRF-BD-15-004A). E-mail:[e-mail]