Abstract—This study investigated the thermal resistance measurement proposed by NIST to access the thermal resistance of multi-chip LEDs and the relation between the thermal resistances of single chip and the chip in the multi-chip LEDs. It is found that the thermal resistance of the chip in four-chip 7070 LED with one chip power on is lower than the measured thermal resistance of the four-chip 7070 with all chips power on. The low temperature contribution of the chips nearby the chip measured for the thermal resistance is resiponsible fot the low thermal resistance for the four-chip 7070 LED.

 Preview abstract

We presented a low efficiency droop behavior green light emitting diodes (LEDs) with a quaternary content InAlGaN/GaN superlattice electron blocking layer (SL-EBL). The light output power shows a 57% enhancement and only 30% efficiency droop, which is attributed to a smooth band bending with a uniform carrier distribution.

 Preview abstract

This study proposes the effects of phosphor concentration and leadframe reflectivity on the pc-LEDs manufactured by dispensing method. The simulated results show the luminous flux increases as the phosphor concentration increasin It is also found that the CCT of the pc- LEDs decreases as the phosphor concentration increasing.

 Preview abstract

We proposed the relation between the chromaticity of two phosphors pc-LEDs and shingle phosphor white pc-LEDs in this study. The blue chip, green and red phosphors are used to fabricate pc-LEDs. It is found that the chromatic coordinate of the LEDs with two phosphor should relate to the LEDs with single phosphor.

 Preview abstract

The current crowding effect in AlGaN 275 nm deep UVLEDs has been investigated using 2D drift diffusion solver and Monte Carlo ray-tracing method. Optimized condition for both lateral and vertical structure is presented here by changing the spacing between 2 fingers. Graphene as contact layer also has been discussed in this paper.

 Preview abstract

This study proposes the effects of phosphor concentration and leadframe reflectivity on the pc-LEDs manufactured by dispensing method. The simulated results show the luminous flux increases as the phosphor concentration increasin It is also found that the CCT of the pc-LEDs decreases as the phosphor concentration increasing.

 Preview abstract

We developed the 1D Poisson and drift-diffusion Solver by considering the effective tail states and field-dependent mobility to simulate the organic materials, such as NPB or TAZ. With the obtained tail state distribution and the field dependent mobility model, we applied this result in modeling organic light emitting diodes.

 Preview abstract

This study demonstrates the application of DBR structure into the remote phosphor structure to improve the angular CCT deviation in white light-emitting diodes (WLEDs). In the experiment, the LED device with DBR structure yielded nice color uniformity that the CCT deviation can be improved from 1758K to 280K.

 Preview abstract

Optimized electrode patterns of vertical GaN-based light emitting diodes are designed on nanoscale patterned Si substrates. By introducing the device parameters reported from literatures, a uniform current spreading distribution is obtained from our designed electrodes.

 Preview abstract

A new bipolar material, CbzOXD, was synthesized to be the host of emitting layer doped with FIrpic inside an efficient blue phosphorescence organic light-emitting diode. The device showed the maximum efficiency performance, e.g. current efficiency of 25.1 cd/A, power efficiency of 16.8 lm/W and external quantum efficiency of 12%.

 Preview abstract

Resolving failure origins of AlGaN/GaN light emitting diodes (LED) has received intensive study recently. In this research, reverse-bias emissions and deformation of the contact near the surface have been observed in stressed devices moisture conditions. We performed detailed studies on forward and reverse I-V, breakdown current profiles, and optical and material observations to gain insight to failure origins of AlGaN/GaN LEDs. Our studies indicate that the deformation of the contact may cause the device failure.

 Preview abstract

The light-emission diode has a good development in shorter wavelength, the major encapsulates material has a problem for the optics. Therefore we develop a novel material to encapsulate the ultraviolet-light emission diode module. The material of Sol-Gel has higher transmittance for the ultraviolet band and higher thermal stability than silicone.

 Preview abstract

The article focuses on simulation of remote phosphor LED with Tracepro. After designing three different models, we corroborate the circular plate structure is the most efficient. Based on this, we investigated the influence of concentration and thickness of phosphor on intensity and color temperature; hence figuring out optimal parameter settings.

 Preview abstract

This study demonstrates the application of DBR structure into the remote phosphor structure to improve the angular CCT deviation in white light-emitting diodes (WLEDs). In the experiment, the LED device with DBR structure yielded nice color uniformity that the CCT deviation can be improved from 1758K to 280K.

 Preview abstract

In this study, we demonstrated a reduced phosphor use technique that applied to white light-emitting diodes (WLEDs) containing composite silica colloidal photonic crystals (c-SCPhCs) for developing the warm-white LEDs (w-WLEDs). Thus, WLEDs containing c-SCPhCs conducted a reliability analysis test that applied a temperature/relative-humidity at 85 °C/85 with 120 mA for 2500 h, determining no visible degradation in optical performance. We implemented a novel, inexpensive technique to produce high luminous flux w-WLEDs for use as a residential light source.

 Preview abstract

In this study, a technique that saved phosphor use was applied to warm white light-emitting diodes containing composite colloidal photonic crystals to develop the candlelight that exhibits a high luminous flux (52 lm) and an excellent color-rendering index (CRI; 94). A novel, inexpensive technology was implemented to produce high-CRI candlelight LEDs for use as a residential light source.

 Preview abstract

Internal quantum efficiency droop of GaN LED

 Preview abstract