Mn-doped Cu3Se2 nanosheets: Impact of physical characteristics on the photovoltaic performance

The un- and manganese (Mn)-doped Cu3Se2 nanosheets were prepared by the electrodeposition method. X-ray diffraction (XRD) patterns revealed that polycrystalline Cu3Se2 nanostructures were at the tetragonal phase. Field emission scanning electron microscopy (FESEM) images showed that all samples had a sheet-like structure. The photoluminescence (PL) spectra showed that the un- and Mn-doped Cu3Se2 nanosheets had three emission bands in violet, green, and red regions. The absorption spectra also demonstrated that the band gap energy of the Mn-doped samples was increased relative to the un-doped sample. Solar cell evaluation showed that addition of Mn dopant was effective on increasing the solar cell efficiency. Further investigations indicated that these changes were close to different physical properties such as increase in the surface-to-volume ratio, absorption intensity, and carrier concentration with the lowest value of strain.