Extended Data Fig. 5: Simulation of outcoupling efficiency.
From: Perovskite light-emitting diodes based on spontaneously formed submicrometre-scale structures
a, Device structure. A typical reference device consists of a metal layer (Au), a 7-nm-thick MoO3 layer, a 40-nm-thick TFB layer, a 50-nm-thick emitting layer (EML), a 30-nm-thick layer of ZnO-PEIE, a 160-nm-thick ITO layer and a semi-infinite glass substrate. In our new device, the EML is replaced by a layer of perovskite squares distributed with a period P and a duty cycle le/P (where le is the length of the perovskite platelets, and le/P = 50%). The height of the convex structure of TFB is denoted as h and the diameter is set to le + 100 nm. b, Discretized map of the perovskite layer. The scale bar represents 1 μm. x and y are the pixel numbers in units of pixel length a. f(x,y) is the discrete function. c, Module of spatial frequency spectrum. Ux and Uy are the spatial frequencies. d, Refractive indices of different layers in our perovskite LEDs. Optical constants (n, k) of the multilayers were determined using an ellipsometer. Here the optical constants of perovskite are from a continuous FAPbI3 film, which are used in the simulation. e, EQE calculated as the period P and the convex height h. f, Calculated outcoupling efficiency as a function of period P with convex height h = 30 nm. The reference is a device made from continuous perovskite film. The simulation shows that the outcoupling efficiency can be more than 25% over a wide range of periods from 310 nm to 900 nm.
