Modelling of realistic annealing behaviour of amorphous silicon photovoltaic devices

Long-term degradation and annealing behaviour of a-Si mini-modules is investigated in this paper. Four devices were firstly degraded by light and then annealed in the dark at temperatures ranging from 65-85°C. Dark annealing rates were obtained for each temperature. Further annealing with light bias was carried out for two of the devices in order to study the interaction between the light-induced degradation and thermal annealing process. Results demonstrate that the annealing in the dark is strongly influenced by the operating temperature but also dependent on the history of the devices. Annealing is a self-limiting process and is significantly influenced by the light intensity in the short-term exposure, giving rise for a balance-equation for modelling purposes.