Solvothermal synthesis of CMTS quaternary semiconductor nanoparticles with a symmetric kesterite structure: The role of the autoclave filling factor

Abstract

Copper Manganese Tin Sulphide (CMTS) is one of the promising chalcogenide materials and a potential candidate as an absorber material to develop low-cost, ultrathin solar cells. The CMTS (Cu2MnSnS4) quaternary semiconductor nanoparticles (NPs) were synthesized by a solvothermal method utilizing different amounts of autoclave filling ratios. The influence of autoclave filling ratio on the structure, phase formation, morphology, composition and optical properties of CMTS-NPs was studied using various experimental techniques. The autoclave was filled with solution up to 50, 60 and 70 percent of the autoclave volume. According to the FESEM images, the CMTS-NPs are uniform, dense, spherical and with slight agglomeration. The CMTS particles have an average crystal size in the range of 31 to 40 nm for different autoclave filling ratios. The chemical composition for CMTS was obtained from SEM – EDX and it was found that the sample with 60% filling factor had the best structure with atomic percent Cu: 26%, Mn: 9%, Sn: 12%, and S: 53%, which is closer to the optimal values. The XRD results showed that the composition of products was close to the stoichiometry of CMTS with a Kesterite structure. Investigation of different autoclave filling factors showed that 60% is an optimum filling rate to obtain CMTS pure phase with high crystallinity. The CMTS particles had a broad absorption band in the whole visible range with a band gap of 1.38 eV, being promising for photovoltaic applications.