| The organic-inorganic hybrid metal halide perovskite luminescent materials have become an emerging hotspot in the field of optical functional materials and devices.The crystal structure dimensions(3D,2D,1D and 0D),the abundant organic and inorganic components,and the doping of luminescent ions can all be used to tune their photoluminescence(PL).Therefore,it is of great significance to study the synthesis,PL tuning and luminescent mechanism of metal halide perovskite for their development in the fields of white LED lighting and display.Herein,we mainly focus on several 2D and 0D metal halide luminescent materials.The main research results of this paper are as follows:(1)The mechanical grinding enables the formation of Mn2+-doped 2D layered perovskite(BA)2(Pb,Mn)Cl4,which exhibits a orange-red emission from 4T1-6A1 transition of Mn2+.Furthermore,the Mn2+-doped(BA)2PbBr4-xClx(x=0,1,2,3,4)were synthesized by using co-precipitation method.Theoretical and experimental results indicate that the nature of halogens is a critical factor parameter to tune the PL characteristics of Mn2+,and the high-efficient emission of Mn2+(PLQY=60.1%)can be achieved in(BA)2PbBr4.(2)The two-dimensional layered perovskites R2PbBr4-xClx(R=BA+,PMA+,PEA+,x=0,1,2,3,4)and(C6H18N2O)PbBr4 were synthesized by using co-precipitation and cooling crystallization methods.Results indicate that the proportion of halogens(Br/Cl)is confirmed to be a key parameter to fine-tune the energy levels of free excitons(FEs)and self-trapped excitons(STEs),and the white-light emissions are achieved in the halogen hybrid systems of R2PbBr2Cl2(R=BA+,PMA+,PEA+)due to the energy balance between FEs and STEs.In addition,the(C6H18N2O)PbBr4 exhibts a cool white light emission from the intrinsic FEs and STEs.The doping of Mn2+ can supplement the red light region,and the ultra-broad-band warm white-light emission(FWHM＝230 nm)is attributed to the coupling effects of FEs,STEs,and 4T1-6A1 transition of Mn2+,which shows the application prospect in the field of white LED lighting.(3)The multiple quantum wells(MQWs)perovskite(PMA)2(MA)n-1PbnBr3n+1(PMPB)is grown on layered substrates by using in-situ deposition strategy to obtain the narrow-band green emission composites,including Sr3Ti2O7@PMPB,h-BN@PMPB,Al2Ca6CO3(OH)16·4H2O@PMPB and KAl3Si3(OH)2O10@PMPB,which exhibit higher PLQYs compared with PMPB.Results indicate that a synergetic effect of high absorptivity,low defect concentration,and small interfacial area leads to the high-efficient cascade energy transfer in h-BN@PMPB,and it presents a narrow-band(FWHM=32 nm)green emission centered at 532 nm with the improvements of PLQY and stability,which shows the application prospect in the field of LCDs backlighting.(4)The isostructural solid solutions(C10H16N)2Zn1-xMnxBr4(x=0-1)were designed and synthesized,and they present the narrow-band green-light emission at 518 nm with a FWHM of 46 nm.There is no concentration quenching in the solid solution with the increase of Mn2+.Results show the competitive relationship between the Mn-Mn distance and the energy transfer rate between adjacent luminescent centers of Mn2+.The larger the Mn-Mn distance enables all Mn2+centers with spontaneous emission with the lower the energy transfer rate,which leads to the near-unity green emission(PLQY=88.75%)in 0D Mn2+-based halides.A wide color gamut of 104%NTSC for the white LED will result in final industrial applications in LCDs backlighting. |
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