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Colloidal quantum-dot light-emitting diodes (QLEDs) are rapidly gaining recognition as formidable contenders in the realm of next-generation lighting and display devices. Notwithstanding, the journey to commercialization of QLED devices encounters a roadblock in the form of inadequate flexibility exhibited by the electron transport layer, which is typically made of ZnO nanoparticles. The hindrance stems from the substantial specific surface area, existence of surface defect states, and the fixed ZnO bandgap. To surmount these obstacles, we delved into the potential of integrating Mg element as a dopant in ZnO, aiming to enhance the surface chemistry, electrical characteristics, and film morphology of colloidal ZnO nanoparticles. The results clearly indicated that Mg doping played a critical role in diminishing surface defects in ZnO, while simultaneously reducing the density of oxygen vacancies, thereby regulating its electron mobility. Through modulation of the Mg doping concentration, the bandgap width of ZnO can be fine-tuned, leading to the creation of a more suitable electron transport layer. The inverted QLED devices based on Zn1−xMgxO electron transport layers exhibited remarkable advancements, with a peak external quantum efficiency and current efficiency of 6.7% and 29 cd A−1, respectively. These values surpassed those of reference devices by 35 and 28%, underscoring the efficacy of Zn1−xMgxO as a viable approach for enhancing the efficiency of QLED devices. [ABSTRACT FROM AUTHOR]

Vapor equilibrium transport method is used to prepare near stoichiometric lithium tantalate crystals with high quality. However, it is difficult to prepare large-thickness crystals by this method due to its low solid diffusion rate. In this paper, based on the diffusion mechanism of lithium tantalate crystal, the diffusion of lithium tantalate crystal was carried out by asymmetric diffusion process with lithium rich atmosphere on one side of the wafer and congruent composition atmosphere on the other side. The composition and domain inversion field were characterized. The results show that the asymmetric diffusion technique provides a channel for the diffusion of anti-tantalum ion and increases the diffusion rate of anti-tantalum ion and lithium ion in the crystal, which is beneficial to the preparation of large-thickness near stoichiometric lithium tantalate crystal. [ABSTRACT FROM AUTHOR]

Lithium diffusion in lithium niobate crystals with different initial Li2O content ( Cinitial) was investigated under Li-rich environment at 1100°C. Lithium niobate crystals with widely varying diffusion-limited Li2O content profiles were prepared through the vapor transport equilibration (VTE) technique using congruent lithium niobate crystals with different Cinitial, and the profiles were measured through Curie temperature by a thermal analyzer. A Boltzmann-Matano analysis was employed to those profiles to estimate the Li+ diffusivity as a function of Li2O content in lithium niobate crystals. A trigonometric function method was applied to those profiles to correlate diffusion time and Li2O content. The results show that at the same composition of lithium niobate crystals after diffusing treatment, the less the Cinitial, the larger the Li+ diffusivity. The relation between diffusion time and Li2O content of the samples which have different Cinitial and thickness was derived. Based upon the Boltzmann-Matano result, diffusion time can be estimated easily from the relation. It is concluded that increasing Cinitial contributes to shorten the diffusion time for preparing near-stoichiometric lithium niobate crystals through the VTE technique, especially for thick crystal wafers. [ABSTRACT FROM AUTHOR]

In colloid quantum dot light-emitting diodes (QLEDs), the control of interface states between ZnO and quantum dots (QDs) plays a vital role. We present a straightforward and efficient method using a negative corona discharge to modify the QD film, creating a dipole moment at the interface of QDs and magnesium-doped ZnO (ZnMgO) for balanced charge carrier distribution within the QDs. This process boosts external quantum efficiencies in red, green, and blue QLEDs to 17.71%, 14.53%, and 9.04% respectively. Notably, optimized devices exhibit significant enhancements, especially at lower brightness levels (1000 to 10,000 cd·m -2 ), vital for applications in mobile displays, TV screens, and indoor lighting.