The article informs that according to a study by Zhao et al., dominant degradation process for the three-dimensional (3D) CsPbI3 perovskite is the egress of iodine, which can corrode the contacts of the solar cell. It mentions he coated the 3D absorber with an inorganic 2D perovskite layer before capping it off with copper thiocyanate (CuSCN), the design inhibits the egress of iodine and minimizes defects at the interface, thus enhancing the stability and longevity of the device.