Effect of Al-, In-, and Mg-doping in the ZnO on the structural, electrical, and optical properties of ZnO/CH3NH3PbI3 heterostructure

The creation of ZnO/CH3NH3PbI3 heterostructures with Aluminum (Al), Magnesium (Mg), and Indium (In) doped ZnO serving as an electron transport layer is the aim of this work. A favorable orientation for the CH3NH3PbI3 absorber layer crystallizes in the tetragonal phase [220], while ZnO crystallizes in the hexagonal phase [100]. This information is yielded by x-ray diffraction analysis. Al, In, and Mg doping of the transport layer has a significant effect on the optical characteristics like absorption and extinction coefficients, optical gaps, and optical and electrical conductivity. The UV-visible characterization of the heterostructures reveals that n-type doping can raise ZnO gap energy from 3.15 to 3.42 eV. The band gap energy of CH3NH3PbI3 is around 1.53-1.55 eV. Additionally, the absorption coefficient of each sample is high, it exceeds 105 cm-1 . The ZnO thin films, both undoped and doped (with Al, In and Mg) exhibit an increase in refractive index from 1.97 to 2.13. The best dopant is found to be In. The refractive index of films composed of CH3NH3PbI3 is 3.13.