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# [Moved]: How to calculate power conversion efficiency for this LED using Silvaco?

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#### winsomeharis86

##### Newbie level 5
Basically I want to find the conversion efficiency of the LED that I simulated on Silvaco TCAD. The results which I obtained on Silvaco are attached herewith. Kindly let me know how to calculate its efficiency.

1. Current-Luminous Power Curve

2. Current-Voltage curve (IV curve)

3. Power Spectral Density-Wavelength curves at 3.5 V, 4 V and 5 V

Re: How to calculate power conversion efficiency for this LED using Silvaco?

Hi

You need the upper two charts.
In the first chart you see the luminous power.

Multiply the current of the first chart with the relating voltage of the second chart.

Then e = P_lum / P_elektr

Klaus

winsomeharis86

### winsomeharis86

Points: 2
Re: How to calculate power conversion efficiency for this LED using Silvaco?

did you want an equation graph or just a rough answer?

Obviously efficiency is not high.
Pout=3.5mW.Pin=25W or 140 ppm efficiency

Re: How to calculate power conversion efficiency for this LED using Silvaco?

Multiply the current of the first chart with the relating voltage of the second chart.

Then e = P_lum / P_elektr
Yes but the efficiency numbers resulting from the data are extremely low (< 0.02 %). Recent LEDs have an efficiency of 10 % and more. Is it a very bad LED technology or a calculation error?

Re: How to calculate power conversion efficiency for this LED using Silvaco?

Data looks to be 1000x lower than expected for 435 nm Blue power LED.

Also the curve is accelerating upward in efficacy instead of declining.

Re: How to calculate power conversion efficiency for this LED using Silvaco?

Data looks to be 1000x lower than expected for 435 nm Blue power LED.

Also the curve is accelerating upward in efficacy instead of declining.

Thanks guys. Here is the new graph that I just simulated. Previous one was just for simulation/analysis purpose. Also pl. note that in Silvaco, currents unit are taken in Amp per micron (A/um). So from the analysis and graph presented just now, I should expect power conversion efficiency to be

Eff=Luminous Power/Input electrical power

Here Luminous power at 5 V = 3.2 W/cm

And Input electric power = (5 V)*(0.00012 A/um) = (5 V)*(1.2 A/cm) = 6 W/cm

So Efficiency=3.2 / 6 = 54% (theoretical)

Is there any way to use Power Spectral density curve as well to get efficiency? Also how I can find External Quantum Efficiency with these graphs? Pics are attached herewith

1. Current-Luminous Power curve

2. Cuurent-Voltage (IV) curve

3. Power Spectral density

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Re: How to calculate power conversion efficiency for this LED using Silvaco?

Can anybody let me know how I can find the External Quantum Efficiency of the LED device using above figures or is there another way out to find EQE?

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