Advanced hermetic encapsulation of perovskite solar cells: the route to commercialization†
Though perovskite solar cells (PSCs) are rapidly emerging into the photovoltaic (PV) community, their long-term stability raises huge concerns for their future commercialization. PSCs are sensitive to humidity and temperature. A hermetic encapsulation is crucial for PSCs not only to prevent them from external environmental effects but also to avoid leakage of Pb-containing materials of the cells. An advanced laser-assisted glass-frit encapsulation method is developed to seal HTM-free PSCs. The long-term stabilities of the laser-sealed devices are examined under harsh environmental conditions of humidity and temperature exposure tests. The hermetically sealed PSCs have passed 70 thermal cycles (−40 °C to 85 °C) and 50 h damp heat (85 °C, 85% RH) tests according to the IEC61646 standard. The power conversion efficiency of hermetically encapsulated PSCs remained constant for 500 h under humid air feeding exposure (80 ± 5% RH); non-hermetically encapsulated devices degraded after ca. 50 h. This work indicates that the hermeticity level of an encapsulation plays a key role in the stability of the devices in a humid environment. Therefore, a hermetic encapsulation is vital for the industrialization of PSCs.