A holistic framework towards understanding the optical and dielectric behaviors of CH3NH3PbCl3 perovskites/graphene oxide hybrid films for light absorbing active layer

In this work methylammonium trichloride CH3NH3Cl3 (MACl), methylammonium lead trichloride CH3NH3PbCl3 (MAPbCl), and graphene oxide (GO) doped methylammonium lead trichloride GO-CH3NH3PbCl3 (MAPbCl:GO) perovskite based thin film coatings deposited onto glass substrates using wet-chemical based spin coating technique at varying GO concentrations (0.025, 0.050, 0.075 ​g/ml), were investigated for their structural, compositional, optical, and dielectric characteristics. Characterizations of the coatings were carried out using XRD, SEM, FTIR, and UV–Vis spectroscopic methods. The XRD patterns and scanning electron microscope images revealed the cubic and regular constructions of MAPbCl and MAPbCl:GO with higher degree of crystallinity. FTIR studies demonstrated different vibrational modes mainly dominated by the organic salt (MACl) in both structures and a few new bonds such as C[dbnd]C stretching, C–H (methyl) bending, CH3–NH3 rocking were observed. Effective changes in the band-gap values were observed due to GO incorporation. A good correlation among different optical parameter such as absorption coefficient, refractive index, extinction coefficient, and dielectric function was also pragmatic. A very high value of the optical conductivity of 2.02 ​× ​1014 ​Ω/nm was shown by MAPbCl:GO (0.05 ​g/ml) perovskite composite. Hence, MAPbCl:GO coatings could be successfully used as a good light absorbing layer in perovskite solar cell (PSC) in an open-air environment and may be explored for further development to achieve a stable structure.