基于自限域激子发光的单基质钙钛矿白光材料及其机理研究

White light emitting material is the core element of lighting application. In view of the blue harmfulness, spectral drift of multi-component white light and excessive dependence on rare earths for current lighting materials, this project plans to use perovskite with excellent luminescence properties as a candidate of lighting materials. The soft lattice characteristics of perovskite make it easy to produce lattice distortion and electro-phonon coupling effect, which will result in the formation of self-trapped excitons and broadening of emission spectrum. Based on that point, a non-toxic perovskite material Cs2AgInCl6 with broad emission spectrum and high PLQYs was developed by our group. However, its expensive raw materials and low color rendering index make it impossible to achieve high quality illumination white light. This project aims at material exploration, emission optimization and mechanism understanding for monocomponent white luminescent materials with low cost and high quality.. After half year of exploration and comparison, as well as sufficient literature investigation and discussion, we have chosen A2BX6 with flexible structure, large tolerance, adjustable electronic dimensions and remarkable STE effect as the main material. The previous research hac achieved a high PLQY of 85% and good air and thermal stability. Based on the strong accumulation in the research of perovskite luminescent materials and combined with my research background of optoelectronic materials and devices, this project will focused on exploration of A2BX6 to obtain its intrinsic materials and photoelectric properties. On this basis, the emission properties of materials was optimized to prepare a monocomponent white luminescent materials having a color rendering index beyond 90 and a color temperature below 5000 K by alloying or doping. Finally, the ultrafast electron diffraction technique is used to explore the coherent phonon motion and lattice dynamics of perovskite materials for quantitative research of the luminescence process of Self-trapped excitons.

白光材料是照明应用的核心要素。发光性能优异的钙钛矿材料，因具有软晶格特性而易产生晶格畸变和电声耦合作用，形成自限域激子，展宽发射光谱，有望实现单基质白光。最近本课题组在Nature上报道了一种基于自限域激子发光的白光材料，然其原料昂贵且显色指数低，无法实现高品质白光。本项目以低成本高品质的单基质白光材料为目标，进行材料开发，性能优化及机理研究的工作。.申请人经过半年的探索，以及充分的调研，最终选定具有结构灵活，容忍度大和自限域激子效应强等特点的A2BX6作为研究对象。前期已经得到85%PLQY和稳定性好的Cs2TeCl6材料，将利用元素调控探索材料体系，并通过合金化和掺杂的方法优化光谱，制备出显色指数>90，暖色调的白光发光材料。最后采用超快电子衍射技术探索钙钛矿的相干声子运动和晶格动力学过程，量化其STE发光过程。

白光材料是照明应用的核心要素。发光性能优异的钙钛矿材料，因具有软晶格特性而易产生晶格畸变和电声耦合作用，形成自限域激子，展宽发射光谱，有望实现单基质白光。最近本课题组在Nature上报道了一种基于自限域激子发光的白光材料，然其原料昂贵且显色指数低，无法实现高品质白光。本项目以低成本高品质的单基质白光材料为目标，进行材料开发，性能优化及机理研究的工作。.申请人经过半年的探索，以及充分的调研，最终选定具有结构灵活，容忍度大和自限域激子效应强等特点的A2BX6作为研究对象。前期已经得到85%PLQY和稳定性好的Cs2TeCl6材料，将利用元素调控探索材料体系，并通过合金化和掺杂的方法优化光谱，制备出显色指数>90，暖色调的白光发光材料。最后采用超快电子衍射技术探索钙钛矿的相干声子运动和晶格动力学过程，量化其STE发光过程.