Vincent Tsai

Cohort 1



Characterisation of Radiative and Non-Radiative Charge Carrier Lifetime of Solar Cells using Optical Methods

Recombination of charge carriers in semiconductors has a major impact on charge carrier lifetime and thus affects the efficiency of photovoltaic (PV) devices. The charge carrier lifetime of solar cells are limited by defects and impurities in the semiconductor material, which are known as recombination centres. The ability to characterise charge carrier lifetime and recombination centres is very useful during the fabrication process of solar cells to improve efficiencies of finished PV devices. When measuring charge carrier lifetimes of solar cells, different measurement techniques can yield widely differing results for the same material or device. The difficulty with comparing these types of measurements is because the property of a carrier within the semiconductor is being described rather than the actual properties of the material itself. One such characterisation technique of charge carrier lifetime is time-resolved photoluminescence (TRPL). The charge carrier lifetime numerical obtained from TRPL represents only the radiative charge carrier lifetime as only the optical emission is being measured. However, charge carrier lifetime is limited by non-radiative recombination. Through only TRPL measurements, non-radiative recombination lifetime cannot be quantified. Furthermore, there is no consideration in separating the radiative recombination from the non-radiative recombination charge carrier lifetime. The aim of this work is to develop a measurement system capable of measuring and distinguishing between radiative and non-radiative recombination charge carrier lifetimes in solar cells