Performance of amorphous silicon in the initial, degraded and annealed states under varying spectrum, irradiance and temperature

This work analyses and discusses the performance of amorphous silicon (a-Si) single junction mini modules in three main states: in the initial non-degraded, as purchased state, in the degraded state after light-soaking and in the recovered state after thermal annealing. The experimental set-up and applied methods of controlled indoor light-soaking and thermal annealing are detailed. Device performance measurements are carried out indoors under varying spectrum (E), light intensity (G) and temperature (T). Measurement results have shown a reduction in STC power of up to 27.5% during the first 250h light soaking and a recovery of 56% of the performance losses after annealing for 250h at 80°C in the dark. After light soaking, devices also showed a reduction in low light performance and an increase in temperature coefficients, which to some extent reversed during the annealing process.