Quantum efficiency is a key factor to determine the conversion from sun light to electrical energy. It is essential characteristic of solar cells design. The seminar on Quantum Efficiency Measurements in Solar Cells was organized by PV Test Laboratory of Hong Kong Science and Technology Parks (HKSTP) on 31 March 2011.
The speaker was Dr. Pawan Bhat (Founder and Chief Technology Officer, ProtoFlex Corporation) and he introduced the testing of quantum efficiency on solar cells included theory and some applications.
Quantum Efficiency (QE) is the ratio of the number of electrons which exit the solar cell per incident photon at each wavelength.
There were two types of QE. One is external quantum efficiency (EQE) and the other is internal quantum efficiency (IQE).
Then Dr. Bhat introduced the structure of solar cells. He explained the light trapping in thin-film silicon solar cells for superstrate and substrate configurations
The calculation of IQE derived a diffusion length was discussed.
The following diagram showed diffusion length from the slope of the inverse IQE-1 plotted against the optical absorption length.
It showed the different bias for carrier injection and real solar cell conditions.
The different samples' QE measurement spectrum were showed including Mono-Si, CIGS, GaAs and a-Si:H.
Hybrid material cell was demonstrated (e.g. A-Si:H/micro-Si:H TANDEM).
The QE equipment was described.
After the theory session, the practical session was performed in the Photovoltaic Test Laboratory (PVTL).
Photovoltaic Laboratory (PV Test Lab) of Solar Energy Technology Support Centre (SETSC) - http://lab.hkstp.org/e/default_home.asp?url=/e/customize/analysis_solar.asp
ProtoFlex Corporation - http://www.protoflexcorp.com/