In spite of substantial improvement in device performances of perovskite solar cells, instability is found to be the main bottleneck of its commercialization. One of the possible reasons behind this instability is the movements of ions across the interfaces of perovskite solar cells. Number of approaches have been put forward to encounter the intrinsic and extrinsic degradation of perovskite solar cells .In our previous study, we have shown that thin layer of atomic layer deposited alumina (30 nm) on top of the devices has significant effect on overall device performance and enhanced stability (over 7000 hours). The coated devices (encapsulated) show substantially stable performances compared to uncoated devices(unencapsulated) under different ambient conditions. Importantly, the encapsulated devices reveal low ionic accumulation resulting significantly lowered hysteresis.¹ Furthermore,in our recent study,all the experimental evidences such as lowering of capacitance in the electrode polarization regime with negligible non-capacitive current and above all the absence of the s-type kink in the J–V characteristics unequivocally indicate better interfacial quality in encapsulated devices .Along with spiro-OMeTAD conductivity measurement ensures ALD chemistry produces considerable improvement of the conductivity of the spiro-OMeTAD hole transport medium (HTM), resulting in electronic modification of the perovskite/HTM interface. As a result, the modified interface provides better hole extraction and lesser ionic accumulation at the interface, resulting in a significant lowering of the burn-in decay and nearly unchanged charge transport parameters explicitly under the course of continuous operation. In contrast, for pristine devices the inefficient charge extraction, probably due to higher charge accumulation across interfaces, can be the primal cause that paves the way to the degradation of the devices. Based on our observations, we suggest that interface degradation takes place before the material degradation is initiated.Henceforth,these results open the way for the development of encapsulation systems that act simultaneously on both the active layer performance and the long term stability beyond conventional encapsulation that merely acts as a blocking system, with no direct effect of the working behavior of the active layer.