Preparation And Properties Of Organic-inorganic Perovskite Organic-silicone Composite Materials

The organometallic halide perovskite?OMHP?with the ABX₃ structure,as a novel semiconductor material,has many excellent optical properties,such as high carrier mobility,long diffusion length,and good luminescence efficiency.Moreover,it is simple to prepare on a large scale and with low cost.These characteristics make it widely studied and applied in optical devices.However,commercial applications are limited due to its inherent instability.How to improve the stability of OMHP materials has become a key issue in the research.This paper has carried out the following work around this topic:The ultra-stable MAPbX₃/silicone oil nanofluid was prepared by simple solution-method,and its structure and properties were characterized in details,which proved its excellent stability and good optical properties.At the same time,the stability of bare MAPbBr₃ NCs in toluene and other organic solvents was also determined.It was found that the fluorescence intensity of MAPbBr₃NCs/dimethicone nanofluids with a relative quantum yield of 47%was maintained and improved from tens of minutes to ten days after water addition.The thermal stability and light stability are greatly improved under the conditions of high temperature and continuous ultraviolet?UV?irradiation.In addition,dimethyl silicone oil,vinyl silicone oil with different viscosity and hydrogen-containing silicone oils with different hydrogen contents were used to prepare a homogeneous MAPbBr₃ fluorescent nanofluid.In the tests for stability,the higher viscosity,the better stability in the presence of water.And the higher the hydrogen content,the worse the water stability.There is Reasonable explanation of its mechanism.The stability of MAPbBr_3-xCl_x and MAPbI₃/dimethylsilicone oil nanofluids emitted by blue and red light was also determined in details.Based on the ultra-stable OMHP fluorescent nanofluids,the application in the field of optoelectronics is further explored.First,the potential applications of nanofluids in optical systems and LED color converters were demonstrated.Next,silica is used as a nanofluid absorber to prepare MAPbX₃/dimethylsiloxane/SiO₂powders emitting characteristic fluorescence.The powder as a fluorescent additive is laminated and cured with PMMA to form luminescent films.Its good stability was characterized,which provides great possibility for the practical application of perovskite nanocrystals.In addition,OMHP nanocomposites are mixed with PMMA to produce green and red LEDs.The OMHP/hydrophobic silica composites were synthesized by simple wet-chemical and mechanochemical methods,superhydrophobic fumed silica as a matrix.The concentration of the perovskite precursor in wet-chemical synthesis has an effect on the optical properties of the composite powder.Higher concentrations of perovskite will form larger crystals in the surface of the hydrophobic silica agglomerate with reduced fluorescence intensity.The composite materials obtained by the two methods have good optical properties and stability.By adjusting the reaction parameters,fluorescent composite with quantum yield of 40%was successfully prepared,and it was with good water resistance,temperature and UV resistance.Ultra-hydrophobic perovskite/silica composite powders,films and nanofluids were prepared by adjusting the halide content in the full spectrum.Green fluorescent materials were also successfully prepared by mechanochemical method.