Speaker
Description
Thin film Kesterites (CZT(SSe)) are currently the most promising photovoltaics (PV) materials for new niche markets such as Building-integrated PV (BIPV) and Product-integrated PV (PIPV) due to their composition based on earth abundant elements and also to their promising photovoltaic device performance. Their tunable bandgap (between 1-1.5 eV) renders them particularly suited also for their integration in more complex devices such as in bi-facial or tandem structures using a transparent back contact. Especially in this case, the use of a transparent back contact requires the incorporation of a layer at the interface to improve the back contact band alignment. In that sense, transition metal oxides (TMO) have proved to be useful thin films for enhancing the characteristics of the solar devices, especially when used at the back/front interfaces of the absorber, since they contribute to the band alignment and thus the carrier injection. Another promising strategy for the front interface consists in changing the alkali nature and content during the deposition of the CdS buffer layer.
Therefore, in this work we present the most recent results of X-ray Photoelectron Spectroscopy (XPS) characterization of (1) the back interfaces in Kesterite-based solar using functionalized transparent conductive oxides consisting on different TMOs used onto the FTO (fluorine doped tin oxide) back contact, with/without Molybdenum on top, and (2) the front interfaces of absorbers using CdS layers with different alkali strategies. The characterization results of these interfaces will give further understanding on the mechanisms enhancing the band alignment of the back and front layers with the absorber to achieve a better performance of Kesterite devices.