In thin film solar cell technology, materials with Kesterite structure are very promising, with efficiency up to 12.6 %. In the case of Si containing S or Se based kesterite, the band gap could theoretically be adjusted between 1.6-2.1 eV as confirmed by first principle calculations and optical measurements on single crystals. This will help to pave the way for this technology to become a suitable top cell candidate for tandem devices (e.g., based on already available high-efficiency crystalline silicon (c-Si) bottom cells).
The subject is related to the recently accepted European Project SWInG-project (Development of thin film Solar cells based on WIde band Gap kesterite absorbers), in which UGent is partner, together with IMEC and different other partners from The Netherlands, Germany and Sweden.
The aim of this thesis is to characterize CZTSe thin film solar cells with different bandgaps for tandem application, using advanced electrical characterization techniques (mainly admittance spectroscopy AS, capacitance-voltage C-V, current-voltage J-V and external quantum efficiency EQE measurements).
Modelling and simulation of the physical and electronic operation of these cells will be performed using the software Scaps (Solar Cell Capacitance Simulator 1-D) developed at ELIS. The software Scaps will be used to develop a reliable device model which will be able to properly interpret the measurements results and allow to define and understand the effect of interface properties (band alignements), defect states,…etc, on the device performance. The development of such model will establish the design rules for device improvement.