Red Light-Emitting Diode Based on Blue InGaN Chip with CdTe x S(1 − x) Quantum Dots

Abstract

Thioglycolic acid-capped CdTexS(1 − x) quantum dots (QDs) were synthesized through a one-step approach in an aqueous medium. The CdTexS(1 − x) QDs played the role of a color conversion center. The structural and luminescent properties of the obtained CdTexS(1 − x) QDs were investigated. The fabricated red light-emitting hybrid device with the CdTexS(1 − x) QDs as the phosphor and a blue InGaN chip as the excitation source showed a good luminance. The Commission Internationale de L’Eclairage coordinates of the light-emitting diode (LED) at (0.66, 0.29) demonstrated a red LED. Results showed that CdTexS(1 − x) QDs can be excited by blue or near-UV regions. This feature presents CdTexS(1 − x) QDs with an advantage over wavelength converters for LEDs.

Aharonov–Bohm interferences in polycrystalline graphene

“…Indeed, similarly to structural defects, chemical impurities with a reasonable concentration can also induce scatterings on the charge transport (see Fig.S6 in the Supplementary Information [52]). Experimentally, several techniques (e.g., atomic force microscope lithography, solution-phase oxidation, photoexcited charge transfer, ...) to create graphene oxide barriers in graphene have been demonstrated [44][45][46][47][48][49][50]. Remarkably, these barriers whose widths are down to sub-20 nm and tunable oxidation level (i.e., oxygen impurity density) have been successfully achieved.…”

“…The impurity density can be further tuned using thermal, chemical and/or electrochemical reduction methods [60][61][62][63][64], for instance, as performed in ref. [47]. In Fig.5, magnetotransport through graphene ribbons containing two narrow (10 nm width) oxygen impurity barriers is presented with different impurity densities n I (O/C ratios).…”

“…Besides the observation of AB interferences in these structural defective systems, we will additionally demonstrate that the approach presented in this work can also be extended to graphene systems containing two parallel graphenic barriers with functional impurities, particularly, including oxygen impurities, which can be experimentally achieved as in refs. [44][45][46][47][48][49][50].…”

Green Phosphors Based on 9,10-bis((4-((3,7-dimethyloctyl)oxy) phenyl) ethynyl) Anthracene for LED

“…Light-emitting diode (LED) lamps using phosphor conversion of 350–480 nm LED radiation have drawn much attention, and are notably expected to replace traditional illumination sources due to their superior features such as low power consumption, long lifetime, high efficiency, small volume, and low maintenance [1,2,3]. The InGaN-based white light-emitting diode (WLED) is a new kind of solid-state illumination technology, the efficiency of which has already surpassed that of traditional incandescent bulbs and fluorescent lamps [4,5,6,7,8,9,10,11]. WLEDs can be achieved by the incorporation of tricolor phosphors (blue, green, and red) with near-UV-InGaN chips or phosphors (green and red) with blue InGaN chips.…”

“…Phosphor materials play a very important role in WLEDs [4,5,6,7,8]. Although near-UV-InGaN chips can offer higher energy to pump the phosphors, they also present low photochemical stability under ultraviolet UV irradiation [9,10]. As a result, it is necessary to develop phosphors which may be excited by blue InGaN LED chips that have high levels of efficiency and small thermal quenching.…”