Flexible kesterite solar cells on ceramic substrates for advanced thermal processing

Flexible CZTSSe solar cells were fabricated on 40-micron thick zirconia substrates compatible with R2R fabrication. Lower thermal budgets by a factor of 25 - 150 and superior temperature stability could not only drastically reduce the energy budget and processing time but also enable the study of radically new annealing profiles such as ultrafast ramping and cooling rates that are impossible on glass. Higher purity than soda lime glass also offers improved control of critical elements such as sodium. Initial tests achieved efficiency of 11.5 % with V_oc =452mV, FF =66 % and Jsc = 38 mA/cm².