Room-temperature synthesized formamidinium lead halide perovskite quantum dots with bright luminescence and color-tunability for efficient light emitting

Abstract

Although organometal halide perovskites have garnered enormous interest as solution-processed absorbing layers in solar cells with power conversion efficiencies breaking 20%, nonetheless seldom effort has been made to light emitting devices fabricated from formamidinium lead halide perovskite quantum dots (QDs). Herein we demonstrate a facile and low-cost room-temperature synthesis of highly luminescent and color-tunable formamidinium lead halide perovskite QDs (FAPbX3, X = Cl, Br, and I or mixed halide systems Cl/Br and Br/I) using inexpensive commercial precursors. Through compositional engineering, the photoluminescence emission spectra are readily tunable in the range of 430–690 nm, covering most of the visible spectral region. The photoluminescence (PL) spectra of FAPbX3 QDs are of the characteristics including narrow emission line-widths of 16–34 nm largely, high quantum yields (QYs) of as high as 88%, and radiative lifetimes in the range of 19.8–53.0 ns. Furthermore, FAPbBr3 QDs exhibit single decay dynamics and nearly non-blinking at single-dot level have been observed. We also demonstrate the green light emitting diodes (LEDs) based on the as fabricated highly efficient perovskite QDs, which shows a high efficient luminance of 403 cd m−2, and a moderately high max external quantum efficiency (EQE) of 2.8% after optimizing the thickness of the perovskite QD layer. Additionally, the LEDs based on FAPbBr3 QDs demonstrate good stability of emission peaks with increasing applied voltage. These results indicate that FAPbX3 QDs have great potential application in lighting devices.