Preparation And Properties Of Metal Halide-based Optoelectronic Devices

The proposal and progress of the national green development strategy sparked the development of photovoltaic devices,thus making them gain enormous research interests.Although the device based on traditional materials like Si and CdTe have already been widely applied in daily life,their high expense,complex manufacturing process and limited size make them hard to meet the ever-increasing demand of modern applications.Metal halides emerged as promising candidates and achieved a lot due to their abundant precursor materials,flexible design,etc.Among them,CsPbI₃ has been widely used in the research of solar cells owing to its suitable bandgap and outstanding stabilities.However,restricted by a large number of carriers undergoing non-radiative recombination due to the high defect density,the open-circuit voltage loss of such devices is higher than organic-inorganic hybrid counterparts.Besides,lead-based metal halides show great promise in X-ray detections with excellent X-ray absorbance.However,the diversification of object shapes and the ever-increasing demand for bio-safety detection triggered us to develop ultra-flexible and non-toxic detectors.In view of the above problems,multiple strategies were adopted to reduce transmission loss and realize high-performance metal halide photoelectronic devices which meet the development of The Times,like organic ion doping,substrate innovation and non-toxic materials exploration.Detailly illustrated as follows:（1）Introducing GAI dopant in CsPbI₃ thin films can decrease open-circuit voltage loss in CsPbI₃ solar cells,which is induced by nonradiative recombination.The film morphology,bandgap and defect density of CsPbI₃ film are dramatically influenced by GA⁺dopant concentration.Finally,the optimal device exhibited a superb PCE of 19.05%and an open-circuit voltage of 1.14 V.（2）Novel nuclear track-etched porous polyethylene terephthalate（PET）was developed for ultra-flexible X-ray detector fabrication.The vertical channels endow the device with improved charge collection efficiency and operation stability by blocking ion lateral diffusion and environment attacks（e.g.moisture and oxygen）.Eventually,our ultra-flexible（bend radius<0.5 mm）X-ray detector exhibits a high sensitivity of6722μC Gy_air^-1 cm^-2 and a low detection limit of 1.87 n Gy_air s^-1 at an electronic field of10 Vμm^-1.（3）Non-toxic Mn-based metal halide((C₂₅H₂₂P)₂MnBr₄)was designed for high performance non-toxic scintillator.Large Stokes shift（225 nm）and high light yield(76194 N_ph/MeV)endow(C₂₅H₂₂P)₂MnBr₄ with outstanding light output.Besides,large-area(C₂₅H₂₂P)₂MnBr₄ crystal with high transparency was realized through the low-temperature melting process（200°C）,whose high transparency ensures excellent photon transmission process.In light of the above advantages,our scintillator achieved a fast response speed（17 ms）and high-resolution X-ray imaging(20 lp mm^-1).