Synthesis And Optical Properties Of Manganese (Ⅱ) Or Antimony (Ⅲ) Doped Cd-based Hybrid Metal Halide Perovskite Materials

Organic-inorganic hybrid metal halide（OIHMH）perovskites materials are of great interest for their excellent optoelectronic properties,which are highly tunable due to their diverse crystal structures and chemical compositions.According to the composition of the hybrid perovskites ABX₃,a wide variety of selectable organic amines at the A-position,and a variety of metal cations at the B-position,as well as halogen ions X（F,Cl,Br,I）,so the hybrid metal halide materials have diverse crystal structures,while the structure type and degree of distortion of the inorganic metal halide skeleton are regulated by organic cations,thus changing the energy band structure and microscopic interactions of the hybrid halide perovskites.The hybrid halide perovskites can be modified to achieve the effect of modulating their photoluminescent properties.The modulation strategies such as organic cation modulation,halogen ion modulation and dopant ion modulation have been proposed.In the case of the same chemical composition,the dopant ions are introduced through doping treatment to achieve the purpose of regulating the band gap or luminescence center without changing the crystal structure of the substrate to achieve luminescence wavelength regulation,enhance luminescence and improve thermal stability,so as to improve and enhance device performance and stability.In this paper,based on the synthesis of organic amine hybrid cadmium perovskite and adjusting its optical properties,the ion doping is used to improve and regulate the luminescence of the original luminous body and to study its luminescence mechanism.In this paper,based on the synthesis of organic amine hybridized cadmium perovskites,the luminescence of the original substrate was improved and modulated by A or B-site ion doping,and the luminescence mechanism was studied.（1）The anti-perovskites structure of（C₃H₉N）₃Cd₂Cl₇:The single crystals of（C₃H₉N）₃Cd₂Cl₇ and（C₃H₉N）₃Cd₂Cl₇:x%Mn²⁺powder was prepared by thermal slow evaporation and mechanochemical synthesis.The powder x-ray diffraction（XRD）and structure of the single crystal（C₃H₉N）₃Cd₂Cl₇ showed an anti-perovskites structure containing two coordination numbers of tetrahedra and octahedra,and double peaks of emission from two self-trapped excitons（STEs）,STE0 and STE1,were obtained at 365 nm and 542 nm.The Mn²⁺doping produced coexisting green（512 nm）and red（645 nm）emission bands due to the different doping positions.The emission band at 512 nm is derived from the synergistic contribution of tetrahedral-position STEs with a single Mn²⁺d-d transition,while the emission band at 645 nm is derived from the synergistic contribution of adjacent（face-linked）octahedral-position STEs with the Mn²⁺-Mn²⁺pair of d-d transition.The doping of octahedral sites adjacent to Mn ions interacts to produce weak ferromagnetism,and this ferromagnetic（FM）-coupled Mn ions pair,in addition to spin-spin coupling,can effectively couple with optical phonons to form magnetic polaron,which significantly enhances its luminescence with a PLQY as high as76.29%,Up to 3-time improvement compared to undoped substrate samples.And the EMP band present shifts in the range of 300-360 nm with the increase of Mn doping.In addition,When Mn is doped,there is still an emission band of 398 nm,which is designated as local exciton magnetopolariton（LEMP）at this time,but due to the strong electric-phonon coupling effect（S-factor）,EMP and LEMP luminescence does not dominate,and the magnetopolariton luminescence in the band dominates.Its temperature-dependent luminescence intensity variation（PL intensity increases with temperature in the range of 80-160 K and 300-380 K）,long lifetime（microseconds and milliseconds）and the characteristics of Raman spectra(250cm^-1)demonstrate the generation and contribution of self-trapped states.The green and red luminescence features clarify the presence of tetra-coordinated manganese-based d-d transition and six-coordinated manganese based magnetic coupling to d-d transition.（2）The two-dimensional（2D）cadmium-based organic amine hybrid perovskite:the Sb³⁺-doped 2D cadmium-based organic amine hybridized perovskites（HDM）₂Cd Cl₄ and（BAH）₂Cd Cl₄ were synthesized by the hydrothermal method.The doping induced band redshift,and both of them showed highly efficient orange-yellow emission at room temperature.They were derived from the STE of the triplet of Sb³⁺ions in the lattice.The powder X-ray diffraction（XRD）results showed that two structures of 2D₁ and 2D₂（HDM）₂Cd Cl₄ were obtained at different temperatures of 140°C and 180°C.The 2D₁（HDM）₂Cd Cl₄ sample synthesized at 140℃had more XRD impurity peaks,while the 2D₂（HDM）₂Cd Cl₄ sample obtained at 180℃had only a few XRD impurity peaks..Therefore,increasing the experimental temperature can reduce the impurity phase generation.The Sb³⁺-doped 2D₁ and 2D₂（HDM）₂Cd Cl₄:x%Sb³⁺have the same luminescence center at 570 nm.The 2D₁ and 2D₂ structures of（HDM）₂Cd Cl₄:x%Sb³⁺have different PLQYs,and the highest PLQY of 2D₂（HDM）₂Cd Cl₄:x%Sb³⁺is close to unity（99.97%）,which was much higher than the highest PLQY of 2D₁（59.88%）.Due to the 2D crystals have large exciton binding energy,long lifetime,and high carrier radiative complex efficiency,resulting in strong luminescence.However,the relatively high impurity 2D₁（HDM）₂Cd Cl₄:x%Sb³⁺has a very low PLQY due to its high non-radiative complex.In addition,（BAH）₂Cd Cl₄:x%Sb³⁺,which was synthesized by a simple hydrothermal method at 80°C,is also a strictly 2D structure,and its efficient broadband orange-yellow emission band is also derived from the emission of STEs formed by strong electron-phonon coupling,and its emission band is centered at 590 nm with a PLQY of 84.60%.Comparing the structures of the compounds composed of two amine HDM and BAH,the luminescence efficiency of the compound constructed with a single HDM layer between Cd-Cl layers(60%Sb³⁺)is significantly higher than that of the compound constructed with an interlayer bilayer BAH because the former has a higher structural rigidity favoring luminescence,and the two-amine structure produces efficient emission of double excitons.