External Quantum Efficiency

External Quantum Efficiency (EQE) for a photovoltaic device is the number of extracted free charge carriers per incident photon. This ratio is obtained by measuring the photocurrent spectrum of the photovoltaic device under test and comparing it to the photocurrent spectrum of a calibrated photodetector, thereby removing the spectral characteristics of the test system. This video describes the process of obtaining an EQE measurement from a photovoltaic device.

More information on the photonics wiki:

[cmditr]

Described in the video is a DC continuous wave illumination technique. Chopper's are generally implemented in conjunction with a lock-in amplifier to measure signals which are below the noise level of your instrumentation, or when photon dosing of the device should be limited. The devices we measure with this technique, those of moderate efficiencies, produce sufficient photocurrents that chopping is not necessary.

[cmditr]

For the solar cell EQE measurements we are generally measuring thin film donor/acceptor blends of organic polymer and small molecules (P3HT & PCBM, other polymers & PCBM, polymer & quantum dot, or polymer & polymer). The P3HT:PCBM blend is the test system we use as a bench mark because materials are well studied and readily available. Because we synthesize our own quantum dots, we generally blend them with other novel polymers to achieve the appropriate energy level alignment.

[ferasalzubi]

I unterstood up to the point where you copied the photo current values for bothe the photodiode and the test cell, then you pasted the values in your ready spredsheet to get the graph of EQE. Can you please provide more details about how did you calculate EQE values ? which formula did you use? Thank you