Excellent Stability of Perovskite Solar Cells Encapsulated With Paraffin/Ethylene-Vinyl Acetate/Paraffin Composite Layer

Superior encapsulation technology is important for PSCs to prolong their lifetime and realize their commercial application. Paraffin/EVA/paraffin composite encapsulated layers were fabricated with the ambient environment under the thermal temperature of 80 degrees C, which has advantages for simple procedures and low cost. PSCs encapsulated with paraffin/EVA/paraffin and pure EVA layers maintained 95 and 45% of the initial power conversion efficiency (PCE) aged for 1000 h at RH 75%, respectively. Paraffin/EVA/paraffin-encapsulated PSCs were immersed in water for 5 h, which remained 98% of the original PCE, which is far superior to EVA-encapsulated PSCs. High melting point paraffin at 68 degrees C shows better encapsulation than low melting point (60 and 55 degrees C) paraffin, indicating that the high molecular weight of paraffin helps improve the encapsulation performance of PSCs. PSCs encapsulated with paraffin/EVA/paraffin showed better stability of Voc than pure EVA layer because paraffin can inhibit defects, voids, and edges of metal electrodes that quickly expand, and decay. Therefore, paraffin/EVA/paraffin combination encapsulation is an effective strategy, which can form continuous and dense hydrophobic composite encapsulation films with a friendly metal electrode.