Green–white color switchable light-emitting devices based on laterally fused cesium lead bromide perovskite nanowires

Abstract

Inorganic lead halide perovskites are excellent optoelectronic semiconductors; however, little has been known about the characteristics of their nanowire-based light-emitting devices (LEDs). We study the LEDs employing self-assembled CsPbBr3 nanowires as emission layers. They tend to form crystallographic orientation-consistent laterally fused parallel arrays when self-assembling into the emission layer in the device due to Coulomb attraction between such ionic semiconductors. At high nanowire concentration, the LED emits pure green light, and the carriers transport through Fowler–Nordheim (FN) quantum tunneling and direct injection successively. In contrast, at lower nanowire concentration, the luminescence of the LED shifts gradually from green to white with the increasing bias owing to participation of not only the nanowire layer but also the carrier transport layers in the carrier recombination processes. Meanwhile, its carrier transport experiences successively FN quantum tunneling, direct quantum tunneling, and direct injection with the increasing bias. These results highly improve our understanding of the characteristics of perovskite nanowires-based LEDs.

Perovskite Nanostructure Films for Optoelectronics and Photovoltaics

“…Besides the CsPbBr 3 NCs, the corresponding NWs have higher PLQY and lower surface defects, where the light emission of the LED device depends on the concentration of NWs in the EML films. The EML films with a high concentration of NWs exhibit green emission, whereas white emission is observed for the LED devices with low NW concentrations, due to the participation of the carrier transport layer in the recombination process . The LED devices of cyan emitting larger diameter CsPbBr 3 NWs exhibit the maximum luminance and EQE of 96 Cdm –2 and 7.1%, whereas the blue emitting NWs with a lower diameter have luminance and EQE values as 13 Cdm –2 and 0.9%, respectively .…”

“…The EML films with a high concentration of NWs exhibit green emission, whereas white emission is observed for the LED devices with low NW concentrations, due to the participation of the carrier transport layer in the recombination process. 70 The LED devices of cyan emitting larger diameter CsPbBr 3 NWs exhibit the maximum luminance and EQE of 96 Cdm −2 and 7.1%, whereas the blue emitting NWs with a lower diameter have luminance and EQE values as 13 Cdm −2 and 0.9%, respectively. 71 CsPbI 3 also acts as an EML layer in the LEDs depending on the αand δ-phases.…”

Metal Halide Perovskite Nanowires: Synthesis, Integration, Properties, and Applications in Optoelectronics

“…Reproduced with permission. [ 198 ] Copyright 2021, AIP publishing. d) CsPbBr 3 QW arrays‐based spherical LEDs: schematic illustration of the device structure (left), EL image (middle), and angular emission (right) of the spherical device.…”

“…Wu et al demonstrated a green-white color switchable LED device based on laterally fused CsPbBr 3 NWs. [198] The horizontally aligned perovskite NWs were utilized as the emission layer, as shown in Figure 13c, left. It is interesting that, at high NW concentration, the LED emitted pure-green light, and the carriers transported through Fowler-Nordheim (FN) quantum tunneling and direct injection successively (Figure 13c, middle).…”

“…c) Horizontal CsPbBr 3 NWs based green-white color switchable LEDs: schematic illustration of the device structure (left), EL spectra of device A (middle) and B (right) under different driven voltages, devices A and B have high and low NWs concentration, respectively. Reproduced with permission [198]. Copyright 2021, AIP publishing.…”