Question

how to calculate External Quantum Efficiency from I-V-L graph? Explain in details.

Answer 1

we know that quantum efficiency is calculated by the ratio of number of charge carrier acquired by solar cells., to the total number of photons of a particular given energy which is is incident..that on solar cell.

Quantum efficiency is expressed as a function of energy or as of wavelength.minority carriers are collected due to the absorption of photons having certain wavelength. Then we get unity Quantum efficiency of a particular wavelength. Photons having zero energy gap, Quantum efficiency will be zero.

a... In this region blue response is reduced due to front surface recombination

b...a reduction of the overall QE is caused by reflection and a low diffusion length.

c... The red response is reduced due to rear surface recombination, reduced absorption and longer wavelengths and low diffusion lengths.

d... Ideal Quantum efficiency.

e... No light is absorbed below the band gap.So the QE is 0 at long wavelengths.

For most solar cells, due to recombination effects, Quantum efficiency is besides this this same thing affect the collection probability and result in production of Quantum efficiency.
External quantum efficiency,in current-voltage-luminance (i-v-l) graph contains the influence of optical losses, such as reflection and transmission.

Qeff =(Watts light flux/hf)/(current/Qe)
=(Watts light flux *Qe)/(current * hf in ev)

Qeff = Watts light flux/watts electrical.

THANKYOU SIR/MADAM...Hope this helped you.