Modulate The Optical Propertie Of (C₃H₁₀N)₄PbBr₆ Metal Bromide With Manganese（Ⅱ） Doping

Organic-inorganic hybrid metal halides have become a promising new type of optoelectronic semiconductor materials due to their tunable band gaps,high absorption coefficients,long carrier lifetimes,and superior charge transfer properties.Meanwhile,the preparation of most organic-inorganic hybrid metal halides does not require advanced techniques.The chemical formula of organic-inorganic hybrid metal halide is AMX₃,where A is an organic cation（HC（NH₂）₂⁺,CH₃NH₃⁺）,M is a metal cation(Pb²⁺,Sn²⁺,Ge²⁺or Mg²⁺,etc.),X is a halide ion（Cl^-,Br^-or I^-）.The morphology,structure and properties of metal halides can be controlled by different synthetic methods.Besides,doping or alloying by metal ions is also an effective means to improve the properties of metal halides.The performance of metal halides has been effectively improved by the above methods,which has great application potential in the field of optoelectronics.Such as,light emitting diodes（LEDs）,photovoltaics（PVs）and photodetectors（PDs）and other fields.In this thesis,(C₃H₁₀N)₄Pb Br₆ single crystals with cyan emission were prepared by anti-solvent vapor diffusion method,and(C₃H₁₀N)₄Pb_0.85Mn_0.15Br₆ powders with efficient broadband white light emission were further prepared by a green and simple mechanochemical synthesis method.The structure,photophysical properties and stability of the material were systematically explored.The main research results of this thesis are as follows:（1）(C₃H₁₀N)₄Pb Br₆ single crystal:The one-dimensional（1D）organic-inorganic hybrid metal halide(C₃H₁₀N)₄Pb Br₆ single crystal was successfully prepared with anti-solvent vapor diffusion method by using low-cost trimethylamine hydrochloride.The(C₃H₁₀N)₄Pb Br₆ single crystal has a large Stokes shift（165 nm）and a half-peak width（FWHM）of 175 nm under the excitation light of 350 nm,and a broadband emission（emission peak:515nm）was obtained.Its photoluminescence quantum yield（PLQY）was 12.8%.Optical characterization analysis proves that this emission is derived from the typical self-trapped exciton（STE）emission of[Pb Br₆]^4-octahedral distortion.（2）Mn²⁺doped(C₃H₁₀N)₄Pb Br₆:On the basis of(C₃H₁₀N)₄Pb Br₆ single crystal material,Mn²⁺doped(C₃H₁₀N)₄Pb Br₆ was prepared by a green and simple mechanochemical synthesis method.The successful introduction of Mn²⁺ions further expands the light emission range.Thus realizing a high-efficiency broadband white light-emitting organic-inorganic hybrid metal halide(C₃H₁₀N)₄Pb_0.85Mn_0.15Br₆ powder with a PLQY of about 36.1%.The experimental study shows that there is a small amount of adsorbed water on the surface of(C₃H₁₀N)₄Pb_0.85Mn_0.15Br₆ powder,which is also the key to achieve high-efficiency luminescence.Its broadband white light emission is mainly obtained from the STEs state of organic amine-doped lead bromide,the shared Mn Br₆ cluster and the ⁴T₁-⁶A₁ transition coupling of Mn²⁺ions with the help of the dielectric confinement effect of adsorbed water on the surface.At the same time,it is found that there is a nano-scale water layer on the surface of the powder,which can produce a strong dielectric confinement effect and couple with the internal exciton interface to enhance white light emission.(C₃H₁₀N)₄Pb_0.85Mn_0.15Br₆ powder can change from white light emission to red light emission after heat treatment at 100℃,and then turn into white light emission after being exposed to humid air for a period of time,but its structure does not change.Therefore,the adsorbed water on the surface of the material can be removed at 100°C,at which time the magnetic coupling of the Mn-Mn pairs at the adjacent octahedral positions shared by the point in the one-dimensional octahedral chain forms a strong bound state,this results in red light emission.This finding indicates that by regulating temperature and humidity,it is possible to realize applications related to the converted emission of white and red light.(C₃H₁₀N)₄Pb_0.85Mn_0.15Br₆ powder achieved the application of one-component white light emitting diode（WLED）with excellent chromaticity coordinate（CIE）of（0.33,0.35）and correlated color temperature（CCT）in 5733 K.This broadband white light-emitting phosphor has overcome chromatic aberration and self-absorption of hybrid emitters,and realizes the advantages of simple emission control,strong color rendering,low cost and simple preparation method.This means more possible applications such as remote sensing,solid state lighting and displays.