External quantum efficiency measurement of solar cell

Abstract

External Quantum Efficiency (EQE) measurement is one important method that is implemented to observe solar cells' behaviour in a specific range of wavelength. This research measured EQE in different type of solar cells: silicon, dye-sensitised solar cell (DSSC), and perovskite solar cell. The objectives of this research are to understand the correct EQE measurement method and to understand the factors that affect EQE result on the three types of measured solar cells. Dedicated illuminator, monochromator, and lock-in amplifier, as the main equipments, were used in the experiments. The method used was the latest version of the standard for doing EQE measurement, which is ASTM E1021-15. The spectral responsivity (SR) has to be measured first before calculating the EQE value. This value was then validated using current density value obtained from current-voltage measurement. As a result, the silicon has the highest EQE among them all, but it is the perovskite which has the same profile with standard solar irradiance spectrum. It means that perovskite solar cell has the potency to maximise the utilisation of solar irradiance. Some critical points of measurements had also been identified during research. First is the providing of the testing vacuum chamber to minimise the influence of the environment. Second is the importance of regular calibration of the reference photodetector. Third is the illuminated area of reference photodetector. Fourth is the nonlinearity of SR versus light intensity in the DSSC.