Enhanced Photoluminescence in Cd_xZn_1–xS Solid Solution by Suppressing Non-Radiative Recombination for White Light-Emitting Diodes

Abstract

The inevitable defects in conventional II−VI semiconductors, introducing pathways for the non-radiative recombination, substantially lower the photoluminescence (PL) quantum yield. Although considerable progress has been made toward eliminating the defect-induced PL quenching, the low stability that remained after surface passivation or only a small proportion of defects that could be modified via other strategies dramatically limits the whole PL quantum yield of solid-state luminescent materials. In this work, we propose a "defect activation" strategy to improve the luminescent performance of Cd x Zn 1−x S solid solution. A remarkable PL enhancement is realized up to orders of magnitude compared to those of non-activated defect sites. Combining experimental investigations and density functional theory calculations, the PL enhancement mechanism clarified that the sulfur vacancies are activated by electron antidoping from adsorbed oxygen to effectively suppress the defect-induced non-radiative recombination. The unique "defect activation" engineering will open up a perspective for the positive role of defects and inspire more explorations for achieving optimized optoelectronic materials with excellent optical characteristics and high stability for white light-emitting diodes.

A Novel Bubble‐based Microreactor for Enhanced Mass Transfer Dynamics toward Efficient Electrocatalytic Nitrogen Reduction

“…Moreover, diffraction spots from the (111), (200), (220), and (311) planes were observed, among that the favorable (111) plane provided the strongest intensity. To further demonstrate the crystal structure of the Ag NPs, X‐ray diffraction (XRD) was performed (Figure 4e), and four characteristic peaks corresponding to metallic Ag crystals (PDF# 87–0717) [ 44 ] were observed, consistent with the HRTEM and SAED results. Moreover, in the high‐resolution Ag 3d X‐ray photoelectron spectrum (XPS) in Figure 4f, the peaks at ≈375.3 and ≈369.3 eV can be assigned to Ag 3d 2/3 and Ag 3d 2/5 respectively; [ 23 ] this result confirms the presence of the metallic Ag phase.…”

“…[ 43 ] Therefore, Ag NPs were utilized as the catalyst for the eNRR because of their abundant (111) active surfaces. Considering that the properties of Ag NPs strongly depend on their composition, shape, and size, a droplet‐based microreactor system was fabricated [ 44 ] to achieve the controllable synthesis of the Ag NPs based on the efficient mixing of reactants, uniform temperature field, and precise residence time control. Furthermore, according to the LaMer nucleation mechanism and the Lifshitz–Slyozov–Wagner growth model ( Figure a), the synthesis conditions can be optimized to obtain an advantageous morphology.…”

“…Ag NPs were synthesized via a liquid‐phase reduction reaction in an as‐assembled droplet‐based microreactor system under optimal conditions. [ 44 ] Ru/C and Fe/g‐CN were synthesized using a continuous‐flow microfluidic platform involving colloidal formation and thermal decomposition. [ 45 ] The morphologies of the electrocatalysts were characterized by TEM (HT7700, Hitachi Co., Ltd., Japan) and HRTEM (JEM, JEOL Co., Ltd., Japan).…”

Improved optical thermometric sensitivity of Eu3+‐doped calcium niobate phosphor via nonstoichiometric control

“…Therefore, the TL intensity of the trap gradually decreases with the decrease in Nb concentration. It is expected that the decrease in the trap concentration could contribute to the suppression of the nonirradiation process 34 . In addition, the TL position is almost unchanged, indicating that there are no extra trapping centers formed by decreasing the concentration of Nb ions.…”

Advancing Evidence-Based Data Interpretation in UV–Vis and Fluorescence Analysis for Nanomaterials: An Analytical Chemistry Perspective

“…Reliable quantification of nanoparticles absorption, scattering, and emission activities is essential for rational materials characterization, design, and applications as these optical processes differ significantly in their causes, effects, and applications. As examples, metal oxide nanoparticles with strong scattering activities in the UV ranges has been used extensively as sun block, while plasmonic nanoparticles find utilities in biosensing due to their strong scattering in the visible to infrared wavelength range. − The applications of photoactive nanoparticles, referring to chromogenic and fluorogenic nanomaterials, are even more diverse, ranging from photocatalysis, − photoluminescence, − photodynamic therapy, − photoelectronics, − and photothermal energy harvesting, − just to name a few. For these applications, it is the absorbed photons, not the scattered photons, that are directly responsible for chemical reactions in photocatalysis, light emission in photoluminescence, and singlet oxygen generation in photodynamic therapy.…”