Perovskite solar cells (PSCs) have achieved high power conversion efficiency on the lab scale, rivaling the other commercialized photovoltaic technologies. However, stability issues have made it difficult for PSCs to achieve comparable or practical lifetimes in outdoor applications. Here, three different types of hot melt films (polyurethane, PU; polyolefin, POE; and ethylene vinyl acetate, EVA) together with glass sheets are employed to encapsulate printable PSCs. The influence of thermal stress and the encapsulation (lamination) process on cell performance is investigated. It is found that POE and EVA, which are the typical encapsulants for silicon and thin film solar cells, are not suitable for the encapsulation of PSCs due to a high laminating temperature (>130 °C) or corrosion of the perovskite absorber. By contrast, encapsulation with PU can be carried out at a relatively mild temperature of 80 °C, and significantly enhance the thermal stability of the cells. When this encapsulation method is applied to largearea (substrate area 100 cm 2 ) printable PSC submodules, the submodules can maintain 97.52% of the initial efficiency after 2136 h under outdoor conditions (location: 39°19′48″N 114°37′26″E). This work demonstrates the potential of industrially relevant encapsulation techniques to enable the commercial viability of PSCs.

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Printable perovskite solar cells (PSCs) have attracted widespread attention due to the simple fabrication process and low-cost raw materials. However, because no hole transport material is used and the carbon layer possess a relatively low work function of only 4.8–5.0 eV, a significant potential loss exists in printable PSCs, resulting in a relatively low open-circuit voltage (V OC). We employed vanadium oxide (VO x ) to post-treat the interface of carbon/perovskite, and effectively enhanced the photovoltage and PCE of printable PSCs. VO x possesses a high work function of ∼5.39 eV, and thus can facilitate the charge transfer from perovskite to carbon due to a more favorable energy level alignment. The V OC of the devices can be enhanced from ∼892.73 to ∼922.86 mV, delivering an average PCE of 14.47% and a champion PCE of 15.77%. In addition, this post-treatment method can also suppress the hysteresis of printable PSCs. The hysteresis index was reduced from 0.025 to −0.001 with VO x treated cells. This VO x post-treatment method is simple, easy to operate and compatible with various perovskite absorbers in printable PSCs, providing a promising prospect for further applications.