Organometal halide perovskites with promising electro-optical properties have been emerged as leading semiconducting materi-als for solution-processed optoelectronic devices[1-3].Thanks to the great efforts from the photovoltaic community during last dec-ade,the power conversion efficiencies(PCEs)of perovskite solar cells(PVSCs)have risen from 3.8％to 25.2％,surpassing that of poly-crystalline silicon solar cells[4,5].However,more than 90％of the photovoltaic market share is still taken by silicon solar cells.To evaluate the feasibility of PVSCs commercialization,the golden tri-angle including device efficiency,cost and stability needs to be considered.Currently,the device efficiency makes PVSCs compara-ble to crystalline silicon solsar cells.Furthermore,Song et al.[6]have developed a bottom-up cost model to evaluate the manufac-turing cost for PVSCs,which reaches the half of that for silicon solar cells.Therefore,the poor stability of PVSCs becomes the main obstacle for the commercialization[7,8].The degradation of PVSCs is a complex process and various factors affect the device stability.Some strategies were implemented to improve the stability of PVSCs.For example,it has been demonstrated that inorganic hole transporting material such as NiOx exhibits promising potential to improve the stability of PVSCs[9,10].Inorganic cations such as Cs+were employed to replace MA+,which is found as a trigger for perovskite decomposition[11].However,even the PVSCs based on stable perovskite composition and robust charge-transporting materials were found to degrade when they were exposed to the ambient air due to the chemical reactions between perovskite and moisture/oxygen in air[12,13].Therefore,various encapsula-tion technologies were recently employed to increase the lifetime of PVSCs by preventing the stimuli from ambient air.Fig.1 summa-rizes the widely used encapsulation methods for PVSCs including glass-to-glass encapsulation,polymer layer encapsulation,atomic layer deposition(ALD)encapsulation,and transparent conductive oxides(TCO)encapsulation[14-19].