Facile synthesis of sulfide-based chalcogenide as hole-transporting materials for cost-effective efficient perovskite solar cells

Sulfide-based chalcogenide quaternary semiconductors Cu2MSnS4 where M=Zn, Mn, Ni and, Co have emerged as a promising material for photovoltaic application due to their opto-electrical properties, friendly environment and earth-abundant composition. Herein, we report on the surfactant-assisted, solvent-free, hydrothermal synthesis of Cu2MSnS4 (M=Zn, Mn, Ni, Co) nanoparticles and their application in photovoltaics as well. The kesterite and stannite crystal structure of the investigated compounds were confirmed by powder X-ray diffraction. Raman, Photoluminescence and UV-Vis reflectance spectroscopies were employed to study the lattice vibrational and the optical properties. High-resolution transmittance electron microscopy was performed to study the morphology of nanoparticles size, as well as the crystallinity of chalcogenide compounds. In the presence of Cu2MSnS4 with different divalent transition metal ions (M)=Mn2+, Co2+, Ni2+ and Zn2+ as a hole transport material, the perovskite-sensitized TiO2 films showed power conversion efficiencies of 8.35, 6.24, 7.55 and 4.16%, respectively.