Study On The Crystallization Control Of Organic-inorganic Hybrid Perovskite

Organic-inorganic hybrid metal halide perovskites have excellent intrinsic optical and electrical properties,and power conversion efficiency of solar cells has reached 23.7%,which is higher than that of traditional CdTe?CIGS and other amorphous silicon-based cells,it has triggered great attention in the field of photovoltaic.The crystallization property of perovskite film determines the transportation capacity and stability of charge carriers in perovskite film.Therefore,the crystallization control of perovskites is the key factor for the preparation of stable and efficient solar cells.This paper focuses on the crystallization control of organic-inorganic hybrid perovskites films and its influence on the photoelectric properties and photovoltaic performance,including the following three parts:(1)The intercalation of organic cations with different length of chain as ligands into 3D MAPbI3 can control the different structural and electronic dimension of perovskites,revealing the influence mechanism of the size of organic cations on the perovskites structure,crystal orientation,charge transportation and structure stability,demonstrating the contribution of electronic and structural dimensionality on photoelectric properties and photovoltaic performance.(2)We fabricated a new kind of two-dimensional Ruddlesden-Popper perovskite PA2MA4Pb5I16.We control the quantum-well orientation,phase purity and grain size by solvent engineering.The correlation law among film formation process,film properties and device performance are established,and the power conversion efficiency of PAZMA4Pb5I16 solar cells has been achieved up to 10.41%,which leads in the photovoltaic field.(3)We analyse the crystalline phase conversion from PbI2 to MAPbI3 in two-step fabrication process by in situ investigation,revealing the crystalline phase conversion mechanism and the influence mechanism of different PbI2 solvated phase on phase conversion dynamics.We demonstrate the influence of different phase conversion dynamics on film defects and carriers transport,and establish the correlation among dynamics,film properties and device performance.We achieve the complete crystalline phase conversion without thermal annealing,and finally we fabricate perovskite solar cells with superior performance,which provides a new pathway for fabricating perovskite solar cells without thermal annealing.