Thermal stability test on flexible perovskite solar cell modules to estimate activation energy of degradation on temperature

The thermal stability of methylammonium lead iodide (MAPbI3)-based flexible perovskite solar cell (PSC) modules was studied. For this purpose, PSC modules, consisting of 10 serially connected cells with an aperture area of 9 cm2, were heated at 85 °C, 95 °C, and 105 °C for 4000 h. The solar cell parameters were periodically measured by interrupting the thermal stability tests. Evolution of series resistance, short circuit current, and fill factor showed monotonic reduction, whereas shunt resistance and open circuit voltage depicted three stage degradation: (i) initial rapid degradation; (ii) quasi stable range; and (iii) gradual monotonic degradation stages, which are the indication for the presence of several degradation mechanisms. Using the Arrhenius model, activation energy (Ea) of degradation was studied. Ea of 1.062 eV (102.5 kJ/mol) was obtained for the maximum output of the total device. Device lifetime for thermal stability, which is defined as the point where the efficiency has reduced to 80 % of its initial value, was also estimated at module temperature of 45 °C.