High-Efficiency and Air-Stable Perovskite Quantum Dots Light-Emitting Diodes with an All-Inorganic Heterostructure

Abstract

Perovskite light-emitting diodes (PeLEDs), because of its fundamental scientific importance and practical applications in the fields of low-cost light source or display applications, have drawn worldwide attention in recent years. However, PeLEDs available today suffer from a compromise in their emission efficiency and operation stability. In this study, we designed and fabricated a stacking all-inorganic multilayer structure by using inorganic perovskite CsPbBr quantum dots (QDs) as the emissive layer and inorganic n-type MgZnO and p-type MgNiO as the carrier injectors, respectively. Through energy band engineering of carrier injectors by Mg incorporation and their thickness optimization, PeLEDs with maximum luminance of 3809 cd/m, luminous efficiency of 2.25 cd/A, and external quantum efficiency of 2.39% have been realized, which are much better than most PeLEDs from CHNHPbBr films, and comparable with the highest results reported on CsPbBr QDs LEDs. More importantly, the unencapsulated PeLEDs in a continuous current mode demonstrate a remarkable operation stability against water and oxygen degradation. After a continuous operation for 10 h under a dc bias (10.0 V), nearly 80% of the original efficiency of the PeLEDs has been retained, greatly superior to reference and other previously reported devices constructed with conventional organic carrier injectors. Our results obtained open possibilities for the design and development of high-efficiency and air-stable PeLEDs that are not dependent on expensive and less-stable organic carrier injectors.

Emergence of Nanoplatelet Light-Emitting Diodes

“…As an alternative, all-inorganic perovskites CsPbX 3 (X = I, Br and Cl or mixed halide) show better thermal stabilities, which may overcome the notorious stability issue [129,130,131]. In addition, since all-inorganic perovskites can show narrow emission (e.g., FWHM < 20 nm) and excellent PLQY (e.g., ~100% in solution), they have triggered great interest to develop LEDs [132,133,134,135,136]. After the first LED with all-inorganic perovskites developed in 2015 [137], many methods were used to enhance the performance of this kind of LEDs based on 3D nanocubes [138,139,140].…”

Perovskite Quantum Dot Light-Emitting Diodes

“…As for perovskite QDs, several groups have used temperaturedependent PL measurements to study the competition between exciton and free carriers. In Shi's study, temperature-dependent PL measurements were carried out to understand the optical transition mechanisms of the CsPbBr 3 QDs [30]. As shown in Figure 7a, with the decrease of the temperature, only one emission peak can be solved, indicating the absence of structural phase transition.…”

“…In previous reports, conventional carrier injection conducting polymer or small molecules, such as PEDOT:PSS, PCBM, and 1,3,5-tris(2-N-phenylbenzimidazolyl) benzene, have been frequently employed as the carrier injectors in perovskite LEDs [25,33,35,36], but their inherent chemical instability inevitably degrades the device performance; thus, a high-efficiency light emission cannot be sustained over a long running time. More recently, Shi et al present a strategy that addresses simultaneously the emission efficiency and stability issues facing current perovskite LEDs' compromise [30]. Wide bandgap semiconductors, n-MgZnO and p-MgNiO, were employed as the electron and hole injectors to construct CsPbBr 3 QD LEDs.…”

Sputtering Power Induced Physical Property Variation of Nickel Oxide Films by Radio Frequency Magnetron Sputtering

“…Baraik et al 12 grew the NiO epilayer on GaN templates to investigate the band alignment properties for the NiO/GaN heterostructure light-emitting diode applications. And Shi et al 13 used Mg-doped NiO as the p-type layer to design high-efficiency and air stable perovskite quantum dots heterostructure light-emitting diodes. The NiO film has been recognized as a promising p-type conductive material for the fabrication of heterojunction light emitting diodes and laser diodes.…”