Realizing White Emission of Single-Layer Dual-Color Perovskite Light-Emitting Devices by Modulating the Electroluminescence Emission Spectra.

Dual-color emission in a single perovskite layer would make perovskite light-emitting devices (PLEDs) more competitive compared with other display technologies. However, due to the carrier dynamics in a blended perovskite film and the low reaction activation energy of the halide exchange reaction, it is very difficult to achieve the dual-color emission in a perovskite layer. Here, dual-color electroluminescence (EL) emission in a single perovskite layer has been realized by slowing the energy transfer from wide-bandgap energy levels to narrow-bandgap energy levels. Moreover, the EL spectra can be controlled by modulating the composition of the perovskite layer. When the amount of CH3NH3I(MAI) in the precursor was varied, white emission with CIE coordinates of (0.33, 0.34) could be achieved. Our work proposes a new strategy for white emission from PLEDs. Also, the analysis and discussion of carrier dynamics in this work may help to enhance our understanding of the working mechanism of PLEDs.