EFFECT OF ANNEALING TEMPERATURES ON THE STRUCTURAL AND MORPHOLOGICAL PROPERTIES OF THIN CH3NH3PbI3-xClx FILMS

Organometal halide perovskites are promising materials for low-cost, high-efficiency solar cells. The method of perovskie layer deposition and heat treatment play an important role in determining the efficiency of perovskite solar cells. The influence of post thermal annealing of thin CH3NH3PbI3-xClx films deposited by thermal evaporation technique were demonstrated regarding their structural, and morphology properties. The structural properties were studied by x-ray diffraction analysis. The diffraction peaks of the various films are observed, showing the crystallographic structural of the samples. All films before and after annealing crystallized in the orthorhombic phase of CH3NH3PbI3-xClx. The surface morphology of prepared films also studied by Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscope (AFM). The first one showed that CH3NH3PbI3-xClx films exhibited sparse surface coverage on the substrate, and a crake-like morphology with few isolated MAPbI(3-x)Cl(x) islands of sub-micron size can be seen all over the surface. AFM measurements for all prepared films show that the average grain size and the surface roughness increases with the increase of annealing temperature.