Electro-optical characterization of photovoltaic devices

Abstract

In this work, we adapted and improved a commercial system designed to measure the external quantum effiency (EQE) and the internal quantum efficiency (IQE) of commercial solar cells. With this purpose, we controlled and synchronized a monochromator and a semiconductor device analyser Agilent B1500A in order to perform different electro-optical measurements being able to measure very low current signals (~10-13 A). To verify that the system was working correctly, we used a Si solar cell whose ll factor, e ciency and spectral response are tabulated. Furthermore, we used this experimental setup to study a Si-NCs/SiO2 superlattice system deposited on a p-type silicon substrate. In this study, we characterized the I(V ) curve of the devices in dark and under white light illumination. We measured the spectral response and IQE of devices containing different NC sizes. IQE of ~14.2 - 20.5 were achieved in the 850-1000 nm wavelength range, and a shift of the IQE edge to higher energies was observed when decreasing the NC size, demostrating electro-optical quantum confinement.