Luminescent Properties of Sr4Si3O8Cl4:Eu2+, Bi3+ Phosphors for Near UV InGaN-Based Light-Emitting-Diodes

Shen, Wangqing; Zhu, Yiwen; Wang, Zhengling

doi:10.3390/app5041494

Cited by 11 publications

(9 citation statements)

References 20 publications

(17 reference statements)

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“…For Samples A-F, the output powers at 20 and 80 mA were 89. 2 18.2, 18.2, 18.4, and 18.1 V, respectively. The I-V characteristics of Samples B-F were similar to each other.…”

Section: Methodsmentioning

confidence: 95%

“…Recently, high-efficiency GaN-based light-emitting diodes (LEDs) have been used in a wide range of applications, such as full-color displays, traffic signals, automobiles, solid-state lighting, and backlights of liquid-crystal displays [1][2][3]. To achieve the high output power, the chip size of a LED device is typically enlarged for sustaining the high-injection-current operation.…”

Section: Introductionmentioning

confidence: 99%

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Improved Performance of High-Voltage Vertical GaN LEDs via Modification of Micro-Cell Geometry

Horng

2017

Applied Sciences

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Vertical-type high-voltage light-emitting diodes (HV-LEDs) with 2 × 2 micro-cells were fabricated on Cu substrates, and the micro-cell geometry was modified to enhance the optoelectronic performance. The current spreading in micro-cell is most dominantly affected by the distance between electrode and edge of chip. When square cells were combined in a HV-LED, the device performance was poor due to an obvious current-crowding phenomenon that occurred near the electrodes. This was attributed that the electrodes in these four square micro-cells were all far away from the edges, resulting in the severe current-crowding phenomenon. On the contrary, as the HV-LED was prepared with four rectangle, triangle, or L-shaped micro-cells, the electrodes were close to the edges of micro-cells and the current spreading effect can be easily improved. Although a HV-LED connected with L-shaped cells possessed a better current spreading effect and a lower surface temperature, the light extraction was relatively low because of an electrode-shading loss effect. When triangular cells were used to prepare the HV-LED, the device achieved a superior optoelectronic performance compared with that of other cells because of a lower current-crowding effect and a more uniform light emission. After an epoxy package process, a lower forward voltage of 14.9 V and a higher output power of 353.2 mW were obtained using this HV-LED at an injection current of 80 mA. Additionally, the wall-plug efficiencies of this device at 20 and 80 mA were 41.1% and 29.7%, respectively. The results confirm that the design of triangular cell is beneficial for enhancing the optoelectronic performance of HV-LEDs. Furthermore, the fabrication processes of vertical LEDs have high potential for HV-LED applications.

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“…For Samples A-F, the output powers at 20 and 80 mA were 89. 2 18.2, 18.2, 18.4, and 18.1 V, respectively. The I-V characteristics of Samples B-F were similar to each other.…”

Section: Methodsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Improved Performance of High-Voltage Vertical GaN LEDs via Modification of Micro-Cell Geometry

Horng

2017

Applied Sciences

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“…Various ceramic interlayers showed improvements for the thermal conductivity of the base substrates and thus the performance of the device (Yin et al, 2013;Yang et al, 2014;Zheng et al, 2012;Figueroa et al, 2005). One of the solutions is an aluminium nitride (AlN) coating used for heat dissipation in the packaging of LEDs, since this material has a high optical transparency and is chemically and thermally stable (Zheng et al, 2012;Figueroa et al, 2005;Li et al, 2007;Rada & Triplett, 2010;Rada et al, 2008;Zuo et al, 2001;Shinde & Goela, 2006;Shen et al, 2015). However, as in many other new devices, cost reduction is an important requirement.…”

Section: Esd For Ledsmentioning

confidence: 99%

EDHA for energy production, storage and conversion devices

Kelder

Marijnissen

Karuga

2018

Journal of Aerosol Science

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Electrohydrodynamic atomization (EHDA) or electrospraying stands out in thin film deposition because of its unique ability to form charged droplets, initiating higher deposition efficiencies in electrostatic spray deposition. Considering that the quality of a thin film depends on the particle sizes, their monodispersity and uniform distribution on the surface, electrospray is a powerful tool in materials synthesis. Therefore, this review looks at different areas where this novel technique has been used to improve on the overall performance of materials for energy devices, such as solar cells, photoelectrochemical cells, rechargeable batteries and beyond, capacitors, and (O)LEDs, including quantum dots.

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“…However, room for improvements remains, including the internal quantum efficiency of the active region [5,6], the light-extraction technology [7], the current-flow design [8,9], the minimization of resistive loss [10], the electrostatic discharge stability [11], and the color-rendering property via the color mixing [12,13]. Aside these improvements, it is known that, due to their importance, various stress-measured degradation tests, including thermal, electrical, static charges, and moisture, have been developed [14,15].…”

Section: Introductionmentioning

confidence: 99%

Multi-Azimuth Failure Mechanisms in Phosphor-Coated White LEDs by Current Aging Stresses

Peng¹,

Guo²,

Wu³

et al. 2018

Preprint

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Abstract:We have experimentally analyzed multi-azimuth degradation mechanisms that govern failures of commercially-available high-power (1 Watt) phosphor-coated white (hppc-W) light-emitting diodes (LEDs) covered with peanut-shaped lenses under three current-stress aging (CSA) conditions. Comprehensive analyses focus on photometric, chromatic, electrical, thermal, and packaging characteristics. At the packaging level, (a) the decrease of the phosphor-conversion efficiency, (b) the yellow-browning of the optical lens, and (c) the darkening of the silver-coated reflective layer deposited with extraneous chemical elements (e.g., C, O, Si, Mg, and Cu, respectively) contribute collectively to the integral degradation of the optical power. By contrast, Ohmic contacts, thermal properties, and angles of maximum intensity remain unchanged after 3840 h aging in three cases. Particularly at the chip level, the formation of point defects increases the number of non-radiative recombination centers, and thus decreases the optical power during aging stages. Nevertheless, in view of the change of the ideality factor, the dopant activation and the annealing effect facilitate the increase of the optical power in two specific aging stages (192 h∼384 h and 768 h∼1536 h), respectively. This work offers a systematic guidance for the development of reliable LED-based light sources in general-lighting areas.

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Luminescent Properties of Sr4Si3O8Cl4:Eu2+, Bi3+ Phosphors for Near UV InGaN-Based Light-Emitting-Diodes

Abstract: shows stronger blue-green emission with broader excitation in near-UV range. Bright blue-green light from the LED means this phosphor can be observed by the naked eye. Hence, it may have an application in near UV LED chips.

Cited by 11 publications

References 20 publications

Improved Performance of High-Voltage Vertical GaN LEDs via Modification of Micro-Cell Geometry

Improved Performance of High-Voltage Vertical GaN LEDs via Modification of Micro-Cell Geometry

EDHA for energy production, storage and conversion devices

Multi-Azimuth Failure Mechanisms in Phosphor-Coated White LEDs by Current Aging Stresses

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