Transient Metastable Behaviour in Highly Efficient MZO/CdSeTe/CdTe Thin Film Solar Cells

Metastability effects have been investigated in high efficiency MZO/CdSeTe/CdTe solar cells. Different preconditioning procedures have been studied that are used to recover the performance of the devices. J-V characteristics before preconditioning have shown an `S` shaped behaviour which is removed during preconditioning. However, this recovery remained only for 3 days while the devices were maintained under vacuum in the dark. Temperature dependent J-V and capacitance measurements before and after preconditioning revealed the presence of recombination centres and defect levels at the MZO/absorber interface. Previous studies have shown degradation of MZO occurring if the layer is exposed to the atmosphere. Hall effect measurements on the MZO films showed no significant changes after any preconditioning or CdCl
2
treatment.