Reveal how to improve the energy efficiency of green LED

As everyone knows, the performance level of green LEDs does not reach the same red and blue LED. However, black spots can be reduced by reducing current density, using a larger chip, and optimizing growth conditions, and the distance between LEDs of 190 lm/W at 100 mA drive current can be minimized. Osram's Andreas L?ffler and Michael Binder said.
The biggest flaw in LED bulbs is second only to the price of the color that is not ideal. This shortcoming is produced by the process of making white LEDs: the GaN-based blue chip excites the yellow phosphor, mixing the two colors to produce white light. In this way, the red region of the visible spectrum does not contribute much to the light output.
A more advanced method of white LED lighting production - a method of solid-state projection display - that is, red, green, and blue LEDs are mixed to produce white light. The advantage of this method is that it is not limited to a higher color rendering index, but also achieves higher light efficiency and flexible control of color.
To produce an energy-efficient system in a mixed color, a high-efficiency light source must be used. The performance of blue and red LEDs has been significant, and recent technological improvements have led to peak power conversion efficiencies exceeding 81% and 70%, but the performance of green LEDs is far behind. The phenomenon that this GaN-based LED is not very effective is called "green light gap".
Green wavelength band
Increasing the efficiency of green LEDs is a major challenge because of the inability to take advantage of the ideal maturity of materials systems. The III-N series used to create high-efficiency blue LEDs will be less efficient at longer wavelengths, while the more efficient Group III phosphides in the red range will face the same distress; The light emitted by the LED emits shorter wavelengths and the efficiency is reduced. In short, the material system is inefficient in the yellow-green spectrum.
Figure 1: Luminous efficiency of Group III nitrides (green data points) and Group III phosphide LEDs (red light data points) at different wavelengths. The blue line represents the corresponding value of the photometric function of the International Commission on Illumination (CIE) in 1924 multiplied by the electro-optical conversion efficiency (WPE). The yellow-green range is marked with a yellow color and is neither sufficiently covered by the Group II nitride nor by the Group III phosphide. This is the essence of the green gap problem.
For Group III phosphides, emitting light to the green band becomes a fundamental barrier to the material system. Changing the composition of AlInGaP causes it to glow green instead of red, orange or yellow—causing insufficient carrier confinement due to the relatively low energy gap of the material system, eliminating effective radiative recombination.
In contrast, Group III nitrides are more difficult to achieve, but the difficulty is not insurmountable. With this system, the two factors that cause the light to extend into the green band, which causes a decrease in efficiency, are: the decrease in external quantum efficiency and electrical efficiency.
The decrease in external quantum efficiency is due to the high forward voltage required for green LEDs. These devices have a very high internal voltage field. Therefore, at a given voltage, although the band gap is lower, the voltage applied to such LEDs will be higher. A higher drive voltage causes the power conversion rate to drop. The second disadvantage is that the green LED decreases as the injection current density increases, which is trapped by the droop effect. The Droop effect also appears in blue LEDs, but the effect is even greater in green LEDs, resulting in lower operating currents.
(Fig. 2) Comparison of external quantum efficiency between 1mm2 blue InGaN and green GaN at wavelengths of 442nm and 530nm
The cause of the droop effect has caused intense discussion in the nitride industry. Because the loss rate of the droop effect is cubic dependent on the charge carrier density under electroluminescence and photoluminescence stimulation, most of the guesses point to the Auger complex as the cause of the droop effect.
However, there are many speculations about the cause of the droop effect, not only the Auger compound, but also the misplacement, carrier overflow or electron leakage. The latter is enhanced by a high voltage internal electric field.

Open Air Profile Disc Insulator is an assembly of one or more shells with metallic fittings, Glass Electrical Insulators have means for non-rigid supporting. In operation,  Profile Disc Glass Insulator is always connected to insulator string, Suspension Insulator set complete with the fittings is used to carry a line conductor or conductors at its lower end. U70BP-U120BP Profile Disc Toughened Glass Insulator comply with IEC, ANSI standard.

  MAIN DIMENSIONS AND STANDARD PARTICULARS
Currency Designation  U70BP/146M  U100BP/127M  U120BP/127M  U120BP/146M  U160BP/146M  U160BP/155M  U160BP/170M  U160BP/170M
Designation  LXAP1-160 LXAP-160 LXAP-210 LXAP-240
Diameter D,mm 380 380 380 380 420 420 420 420
Spacing H,mm 146 146 127 146 146 155 170 170
Creepage L,mm 365 365 365 365 380 380 380 380
Socket Soupling,mm 16 16 16 16 20 20 20 20
Mechanical Falling Load,KN 70 100 120 120 160 160 210 210
Mechanical Routine Test,KN 35 50 60 60 80 80 105 105
Wet Power Frequency withstand voltage,KV 45 45 45 45 50 50 50 50
Dry Lighting Impulse withstand voltage,KV 90 90 90 90 95 95 95 95
Impulse Puncture Voltage,PU 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8
Power Frequency Puncture Voltage,KV 130 130 130 130 130 130 130 130
Radio Influence Voltage,μv 50 50 50 50 50 50 50 50
Corona Visual Test,KV 18/22 18/22 18/22 18/22 18/22 18/22 18/22 18/22
Power Frequency Electric arc voltage,KV 0.12s/20ka 0.12s/20ka 0.12s/20ka 0.12s/20ka 0.12s/20ka 0.12s/20ka 0.12s/20ka 0.12s/20ka
Net Weight per unit,KG 5.3 5.2 5.3 5.4 7.2 7.2 7.3 7.3

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