On‐Stage Degradation of Solar Cells Studied Using Capacitance Transient and Luminescence Spectroscopies

The light‐ and temperature‐induced degradation (LeTID) of Si‐based solar cells remains one of their common stability issues. The degradation process and affecting factors are still widely discussed. Low‐temperature photo‐ and electroluminescence and deep‐level transient spectroscopy (DLTS) are rarely used in the LeTID studies. The methods can explore only small‐area samples extracted from the cells. A comparison of the fabricated cells in initial, degraded, and regenerated states by these methods is effective only if used for the same location of the cell. The mesa‐diodes fabricated from various locations of passivated emitter and rear contact (PERC) PV cells are mounted on the stages of PL/EL and DLTS setups for the initial state characterization. Subsequently, the diodes are subjected to degradation and regeneration treatments under constant bias, and each state is similarly characterized. All processes and tests are carried out on‐stage, that is, without moving a diode from the stage. Based on the newly obtained and previously reported results, it is suggested that LeTID reflects hydrogen dynamics between extended defects present in solar cells and hydrogen‐containing intrinsic defects formed during/after the contact firing process.