Materials and method for trapping lead leakage in perovskite solar cells

A method of preparing a lead trapping layer, comprising the steps of:

• mixing the acidic cation-exchange resin and the encapsulation resin under vigorous mechanical stirring to form a colloidal mixed resin;
• and
• applying the colloidal mixed resin to a position selected from the group consisting of:
• (1) only on the upper surface of the metal electrode;
• (2) from the top of the device extended downwards to wrap the side of the device;
• (3) on the periphery of the device;
• (4) on the top and bottom of the device;
• (5) between the perovskite functional layer and the first hole-transport layer;
• (6) on the upper and lower surfaces of the perovskite functional layer;
• (7) around the perovskite functional layer;
• and
• (8) between the first electron-transport layer and the metal electrode,
• wherein the lead trapping layer comprises:
• (a) an acidic cation-exchange resin comprising a formula selected from the group consisting of:
• wherein
• each M+is independently selected from the group consisting of Sr2+, Ca2+, Ni2+, Cu2+, Co2+, Zn2+, Mg2+, Ba2+, K+, NH4+, Na+, H+, and Li+;
• and
• each R is independently selected from the group consisting of SO3H, CH2SO3H, PO3H2, and COOH;
• and
• (b) an encapsulation resin selected from the group consisting of an epoxy resin, a silicone resin, an arcrylate resin, and a combination thereof.