Synthesis And Application Of Low-dimensional Perovskites

Halide perovskites are series metal halide materials with perovskite structure.Over dacades,halide perovskites are universally appllied to thin film solar cell devices.Compared to conventional photovoltaic materials,halide perovskites possess high absorption coefficiency,low cost,and promissing power conversion efficiency.Low dimensional perovskites are formed by structral tailoring by introducing large organic spacers.The inert nature of organic spacers will enhance overall stability of perovskite materials.Besides,the reduced dimensionality also lead to remarkable change of their exciton properties.These new materials extended to application of light emitting materials and photo detectors.Here,we developed some new series of low dimensional perovskites,and explored their structure,properties and applications.1.Tin bromide 2D perovskites and their structural transformationWe explored and synthesized lead-free tin bromide Ruddlesden-Popper perovskites,and find an unique hollow layered structrue induced by specific polar solvents.This toxic free low dimensional tin perovskite exhibits broadband emission in visible region with high luminescence quantum yield of 86%.First-principles calculation indicate the broadband emission is associated with the recombination of self-trapped excitons.And the emission is related to geometry of tin bromide anions.An ultraviolet light-pumped white light emitting diode with excellent color-rendering index(CRI)of 94 was fabricated using it together with a commercial-available blue phosphor.2.Perovskite Solar Cells Passivated by Distorted Two-Dimensional StructureHybrid perovskites are series of solution-processable materials for photovoltaic devices.To achieve better performance and stability,interface passivation is an effective method.Here,we selected a biimizole(BIM)molecule as a new passivator for perovskite,and obtained a distorted 2D structure by introducing excess of MAI into lattice.We got 2D-3D perovskite films by introducing BIM into precursor solution.As a result,we get a BIM passivated perovskite solar cell with power conversion efficiency up to 14%.This work paves a new road to interface engineering of perovskite solar cells.3.Other low dimensional structureWe also prepared series new 0D and 1D perovskites,and unveil their struture.These structures will provide good reference for further development of low dimensional perovskites.