| In recent years,metal halide perovskite materials(ABX3,A=MA+?FA+,et al.B=Pb2+?Sn2+,et al.X=Cl-?Br-?I-)rely on their excellent properties,such as larger light absorption coefficient,adjustable optical band gap,longer carrier diffusion distance and carrier life,etc.,show great potential for development of laser and luminescence and other fields,thus becoming one of the hot spots of research in the field of new energy materials.However,the further industrial application of perovskite materials is subject to its instability of water,heat,and light.Therefore,the research on the composition control and stability improvement of perovskitc materials is of great significance.In this paper,based on the structural characteristics of perovskite materials,FAPbI3,MAPbCl3,and CsPbBr3 were used as targeting materials,the inherent properties of perovskite material were improved and the influence of mixed ions on the growth and performance of perovskite single crystal was explored by adjusting the components of A,B,and X in the structure of perovskite material.The design,growth and photoelectric properties of A-site FA+mixed Cs+,B-site Pb2+mixed Fe2+/Fe3+,X-site Br-mixed I-perovskite single crystals were studied,and the effects of mixed ions at different positions on the growth stability and photoelectric properties of perovskite crystals were investigated.The specific contents are summarized as follows:(1)Research on the design growth,stability and photoelectric performance of FA1-xCsxPbI3 single crystal:Large-size FA1-xCsxPbI3(x=0,1,2,3,5%)single crystals with different Cs+ doping amounts have been successfully grown using the inverse temperature growth method;Experiments show that Cs+ can succesfully enter the FAPbI3 lattice and effectively inhibit the phase change of the FAPbI3 single crystal;To a certain extent,it improves its stability;When there are too many Cs+ in the solution,Cs+ in the lattice do not increase significantly;Doping Cs+ makes FAPbI3 single crystals have obvious shallow level defects in the infrared region,so weak fluorescence peaks appear,but basically does not affect the carrier recombination life;In addition,photodetector devices were prepared on FA1-xCsxPbI3 single crystals with different Cs+ doping amounts,the proper amount of Cs+ doping(1%)makes the FA1-xCSxPbI3 single crystal have better photoelectric performance,but the excessive Cs+ content(5%)makes the lattice shrink seriously and reduces the photoelectric performance.(2)Research on the design growth and photoelectric performance of MAPbCl3 doped Fe2+/Fe3+single crystals,and research on the photoelectric anisotropy of(100)and(110)crystal planes of MAPbCl3 single crystals:Crystal size were control by adjusting solution concentration and temperature and two-dimensional nucleation growth mechanism of MAPbCl3 single crystal was proved;Fe2+/Fe3+were introduced into the MAPbCl3 lattice successfully,and caused the lattice expansion,resulting in UV absorption edge red shift;Compared with MAPbCl3 single crystal,the photoelectric performance of MAPbCl3 doped with Fe2+/Fe3+have decreased,showing lower photocurrent and On/Off ratio;In addition,MAPbCl3 single crystals with exposed(110)crystal planes have been grown and the photoelectric response of(100)crystal plane is better than(110).(3)Research on the design growth and photoelectric performance of all-inorganic CsPbIxBr3-x single crystal:On the one hand,pure CsPbBr3 microrod single crystals(MSCs)were grown via anti-solvent method and their growth mechanism and photoelectric properties were studied.The nucleation and growth were controlled by adjusting anti-solvent diffusion rate and ultra-long CsPbBr3 MSCs was obtained successfully;The size of CsPbBr3 MSCs were characterized using SEM and AFM,and layer growth mechanism was proved;The longer crystal plane was determined as(101)plane and grows along the crystal axis[010];CsPbBr3 MSCs has longer carrier lifetime than the single crystal;A single CsPbBr3 MSCs is used to prepare photodetector,which has higher detectivity(*1012)and On/Off ratio(*103)than single crystal.We believe that Cs+ can be transmitted along the channel built by[PbBr6]4-in the direction of[010],and the constructed channel transmission is beneficial to improve the optoelectronic response,but does not reduce the stability of the device.On the other hand,the doped ratio of Br-and I-in X-site were controlled by adjusting the ratio of CsI and PbBr2,I-was introduced into the lattice successfully;Large-sized CsPbIxB3-x single crystals were obtained by adjusting the ratio of three solvents,and I-can be uniformly distributed,leading to lattice expansion,and increaseing the ultraviolet absorption edge,reducing the optical band gap,improve the photoelectric response and has good photoelectric stability.(4)The exploration of the growth of lead-free perovskite single crystal:Two methods were used to grow different forms of MA2MnCl4 single crystal,and it was found to have good and stable luminous performance;The luminous color scale is(0.61,0.39),which can be applied to white LED lighting based on ultraviolet/blue light. |
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