With a lot of effort, researchers have improved the external quantum efficiency of the perovskite LED from less than 1% in 2014 to more than 20% in 2018. However, most reports focus on the material engineering of the perovskite LED device material system, and few reports discuss the light extraction problem in the perovskite LED. With optical study and device verification, it has been concluded that the light extraction is a critical limiting factor for conventional planar perovskite LEDs. In our work, the nanophotonic strategy was used to address this issue. Four pieces of work are included in this thesis. First, the light management in nanostructures is applied for different applications. Second, the nanophotonic substrate is used, and 73% light extraction is achieved. Devices on this...[ Read more ]

With a lot of effort, researchers have improved the external quantum efficiency of the perovskite LED from less than 1% in 2014 to more than 20% in 2018. However, most reports focus on the material engineering of the perovskite LED device material system, and few reports discuss the light extraction problem in the perovskite LED. With optical study and device verification, it has been concluded that the light extraction is a critical limiting factor for conventional planar perovskite LEDs. In our work, the nanophotonic strategy was used to address this issue. Four pieces of work are included in this thesis. First, the light management in nanostructures is applied for different applications. Second, the nanophotonic substrate is used, and 73% light extraction is achieved. Devices on this kind of substrate are made, and a 17.5% high external quantum efficiency is obtained. Third, the growth of perovskite nanowire is explored. Finally, the nanowire LED is studied, together with a novel method to grow the perovskite nanowire arrays with the assistance of the capillary effect. With a 16% external quantum efficiency, the nanowire devices also show better stability and mechanical robustness than thin-film control. Our work on high-efficiency perovskite LED with nanostructures shows that the optimization of the nanostructure geometries is interesting both theoretically and practically. More optical simulations need to be performed to achieve light extraction higher than 73%. In future work, a prediction model for geometry optimization is required, and the stability issue caused by the intrinsic ion migration problem should also be properly addressed.