EFFICIENCY OF CH3NH3Pb(SCN)xI3-x FILMS AS LIGHT-ABSORBER INCARBON-BASED HOLE-TRANSPORT-LAYER-FREE PEROVSKITE SOLAR CELLS

Abstract

The CH3NH3Pb(SCN)xI3-x perovskite films were prepared via the hot-casting method. The surface morphology of CH3NH3Pb(SCN)xI3-x perovskite films with low SCN- dopant levels (x = 0.0625 to x = 0.1875) showed smooth surfaces. However, with high SCN- dopant levels (at x = 0.25 and x = 0.5), rough surfaces with pinholes were produced. The crystal of pure CH3NH3PbI3 (x = 0) film is a tetragonal perovskite structure. The XRD spectra of the CH3NH3Pb(SCN)xI3-x perovskite films (x > 0) showed an additional peak at 12.66° and its intensity increased with SCN concentration. The carbon-based hole-transport-layer (HTL) free CH3NH3Pb(SCN)xI3-x (at x = 0.0625) perovskite solar cell had the optimal SCN¯ dopant ratio, generating a promising cell efficiency of 6.34%, with a good efficiency retention of 79.43% after 30 days of testing, in comparison to a pure CH3NH3PbI3 perovskite solar cell with an efficiency retention of only 26.92%.-