Growth,Structure And Properties Of Solar Cell Materials CH₃NH₃PbBr₃ Single Crystal

Organic-inorganic hybrid perovskite-structured materials CH3NH3PbX3(X=Cl,Br,I),due to their advantages,such as low cost,high photoelectric conversion efficiency,and low-temperature solution-processibility,etc.would be the most suitable materials for the new generation high-efficient solid-state solar cells.In order to optimize the performance of perovskite solar cells,the basic performance study of CH3NH3PbX3 is of great significance.In this paper,we propose to grow CH3NH3PbBr3 single crystals of high quality,study it's the structure,optical and electric properties,and the crystal growth kinetics.The study results will be used for providing materials and theoretical basis to optimize the perovskite solar cells.The main work is as follows:Polycrystalline of CH3NH3PbBr3 for crystal growth was synthesized by a liquid method.The solubility curve of CH3NH3PbBr3 polycrystalline materials in HBr solution was measured.High-quality CH3NH3PbBr3 seed crystals were grown by solution evaporation method,centimeter-sized,CH3NH3PbBr3 single crystals of high quality were obtained successfully in HBr and DMF solvents respectively.Growth dynamics of CH3NH3PbBr3 single crystal was studied by the micro-solution crystallizer device.The average horizontal growth rates of the crystal faces(O11)?(101)and(001)determined are 0.017 57(6)nm/s,0.021 44(4)nm/s and 0.018 65(7)nm/s respectively for CH3NH3PbBr3 grown crystal in HBr solution at 22? temperature,and the largest crystal face is(110);With DMF as solvent,the largest crystal face is(110).The results shows that solvent has great influence on the micro morphology and crystallization behavior of CH3NH3PbBr3 crystal.The crystal structure was determined by X-ray diffraction.The results show that the grown CH3NH3PbBr3 crystal belongs to a cubic system structure with the lattice parameter a=0.592 76nm(7).The peaks of FT-IR spectrum was also assigned.By analyzing the Uv-vis-ir and PL spectra of CH3NH3PbBr3 crystal,it shows the absorption edge is about 545 nn,with a wide absorption band(230 nm to 600 nm),and the forbidden band Eg=2.21 eV.All results suggest that CH3NH3PbBr3 is an ideal candidate solar cell material,and has potential application prospects.