Our mission

The long-term motivation of the project is to create the capability of manufacturing a tandem solar module panel with efficiency above 30 %, using the existing module manufacturing capacity of Si-wafer based solar cells. At this moment, crystalline silicon wafers (c-Si) are (after their interconnection) encapsulated using a glass front plate that provides the environmental protection for the final photovoltaic (PV) module. Our project is to develop a wide band gap thin film (TF) PV material (band gap between 1.6-2.1 eV) with efficiency on the order of 15 %  that can be processed on glass plates of the same dimensions as those used for encapsulation of classical c-Si PV modules. The ultimate goal is to replace the glass front plate of c-Si solar cells by our TF-PV technology, creating a tandem solar module (e.g. four-terminal interconnected device) utilizing the present infrastructure for c-Si solar cells/PV modules.


Schematic of the SWInG long-term motivation. This concept is based on the functionalization of the front glass plate used in c-Si PV module, using a wide band gap TF technology, to create low cost tandem devices.



The project

The aim of this project is to develop wide band gap thin film solar cells based on kesterite absorbers for future application in high efficiency and low cost tandem PV devices. The SWInG working group will focus both on the development of the processes for the synthesis of such solar cells based on the Cu2ZnXY4 (with X=Sn, Si and Y= S, Se) compounds and on the understanding of the physical and electrical properties of the high band gap absorber in order to reach high conversion efficiency. The key research challenges will be: developing up-scalable processes for the synthesis of the absorbers; defining the specifications for high quality wide band gap absorbers as well as suitable back contact and buffer/window layers; assessing the potential of this technology for PV applications. The wide band gap thin films solar cells developed in this project are expected to reach a stable efficiency of 15 % on a laboratory scale and 12 % for a mini-module prototype.


Summary of the strategies to be followed in SWInG to achieve 15 % efficiency