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Potential well
About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.
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TL;DR: The FMMHI method is unique in both the addition of FABr into the PbBr2 precursor solution and the incorporation of small rubidium (Rb+) into the blue perovskite QDs light-emitting diodes (QLEDs).
Abstract: Solution-processed lead halide perovskite quantum dots (QDs) are emerging as one of the most promising candidates for emissive display application. Although perovskite QDs with a full spectrum of visible light emissions have been realized for years, realizing the efficient electroluminescence of blue perovskites at room temperature still faces severe challenges. Herein, we demonstrate both the efficient photoluminescence and electroluminescence of the blue perovskite QDs via a simple FABr-modified multi-cation hot-injection (FMMHI) method. The FMMHI method is unique in both the addition of FABr into the PbBr2 precursor solution and the incorporation of small rubidium (Rb+) into the blue perovskite QDs light-emitting diodes (QLEDs). The addition of FABr into the precursor solution can realize strong quantum confinement effect, large exciton binding energy and high-quality perovskite QD films. Besides, the bandgap can be enlarged by the Rb+-induced perovskite octahedral distortion and strong quantum confinement effect. Excellent PLQYs of 64.5% and 49.8% were achieved for the developed greenish-blue QDs (Rb0.33Cs0.67)0.42FA0.58PbBr3 and deep-blue QDs (Rb0.33Cs0.67)0.42FA0.58PbCl1.25Br1.75 in solid film state. Moreover, maximum external quantum efficiencies (EQEs) of 3.6% and 0.61% were also achieved with an electroluminescence peak wavelength at 502 and 466 nm, respectively, indicating that the perovskite QDs incorporated with Rb+ possess great potential for the development of high-performance blue perovskite electroluminescence diodes.
33 citations
TL;DR: The measured strain is responsible for an unusual band-gap energy increase that is several times larger than the quantum confinement effect, indicating that strain effects contribute significantly to band-edge energies in this and other quantum structures.
Abstract: We report a synchrotron x-ray-diffraction study of the strain field in embedded In0.2Ga0.8As/GaAs ~001! quantum wires of widths 50‐250 nm. Our results show a size-dependent orthorhombic lattice deformation in the wires and a linearly strained interfacial region near the wire sidewalls. The measured strain is responsible for an unusual band-gap energy increase that is several times larger than the quantum confinement effect, indicating that strain effects contribute significantly to band-edge energies in this and other quantum structures. @S0163-1829~96!00948-4# Quantum confinement in low-dimensional semiconductor materials has attracted much interest in recent years because of its fundamental connection to quantum and solid-state physics and its potential impact on semiconductor electronic and optoelectronic devices. 1 These materials are categorized
33 citations
TL;DR: In this paper, a solution-processed near-infrared photodiode ITO/ZnO/PbSxSe1−x/Au, in which ternary PbS xSe 1−x QDs act as the active layer and the ZnO interlayer acts as electron-transporting layer, was demonstrated.
Abstract: Semiconductor quantum dots (QDs) have been the subject for wide research studies owing to their quantum confinement effect. Photodetectors or photodiodes are recognized potential applications for QDs due to their high photosensitivity, solution processability and low cost of production. In this paper, a solution-processed near-infrared photodiode ITO/ZnO/PbSxSe1−x/Au, in which ternary PbSxSe1−x QDs act as the active layer and the ZnO interlayer acts as electron-transporting layer, was demonstrated. The photosensitive spectrum can be broadened by adjusting the molar fraction of ternary PbSxSe1−x QDs. The narrow band edge of absorption and photoluminescence exciton energy of PbSxSe1−x alloyed NCs were blue-shifted from the band edge of the same size PbSe QDs to the band edge of PbS QDs by controlling the S/(Se + S) molar ratio in the synthetic mixture. Efficient electron extraction was carried out by inserting a solution-processed ZnO interlayer between the indium-tin oxide (ITO) electrode and the active layer. Our experimental results show that the solution processing of the ZnO layer can lead to high-performance photodiodes by using photosensitized PbS0.4Se0.6 alloyed nanocrystals as the active layer. The effect of the thickness of the active layer on the device performance was briefly described and a maximum photoresponsivity and specific detectivity of 25.8 A/W and 1.30 × 1013 Jones, respectively, were obtained at a certain thickness under 100 μW cm−2 980 nm laser illumination. The devices are made stably by layer-by-layer ligand exchange treatment.
32 citations
32 citations
TL;DR: In this article, the role of quantum confinement effect and surface passivation of nanograins in optical properties is examined in detail, and the coupling between surface vibrations and fundamental gap Eg as well as the increase of interaction between them at the strong confinement regime (⩽2nm) are proposed for the observable pinning of Eg in luminescence measurements.
Abstract: We report on a spectroscopic study of very thin nanocrystalline silicon films varying between 5 and 30nm. The role of quantum confinement effect and surface passivation of nanograins in optical properties are examined in detail. The coupling between surface vibrations and fundamental gap Eg as well as the increase of interaction between them at the strong confinement regime (⩽2nm) are proposed for the observable pinning of Eg in luminescence measurements.
32 citations