Aging in Different Environments of Cu(InxGa1-x)Se2 Surfaces – ADECS

The ANR project ADECS (Aging in Different Environments of Cu(InxGa1-x)Se2 surfaces) aims to study the chemical reactivity of Cu (InxGa1-x) Se2 (CIGS) solar absorbers in different environments. Improving the stability of solar cells is a key point in the field of solar technology and requires a fundamental understanding of the degradation mechanisms. During the manufacture of a CIGS solar cell, the absorber will undergo numerous chemical interactions with both gaseous (air) and aqueous (buffer layer growth) environments.
In order to understand these degradation mechanisms, as a first step, custom samples (different stoichiometries, presence or absence of Ga gradient) will be exposed to aging in air where the impact of certain degradation factors (relative humidity level, presence or absence of light) will be examined. The chemical evolution of CIGS absorbers will be elucidated through surface analyzes, with particular emphasis on the chemical environment through XPS measurements, but also more in depth through HAXPES measurements. During the different aging, the chemical balance of CIGS is disturbed by the growth of oxides with different kinetics. To better understand this disturbance, and therefore to propose the most relevant degradation mechanisms for CIGS layers, a systematic study of binary and ternary materials from the CIGS ternary diagram will be carried out, in order to see which ones are involved in the degradation.
To complete this aging study, other aging environments will also be studied, on altered and unaltered surfaces. Aging in aqueous environments (by varying the parameters of pH, illumination and the presence of O2) but also in gaseous ones (under acidic or basic vapors) will be explored.