An effective encapsulation method for highly stable perovskite solar cells by introducing a UV absorber with biomimetic textures and heat sinker with a reduced graphene oxide composite layer

In the present study, we developed an effective encapsulation method for highly stable perovskite solar cells (PeSCs). By simultaneously introducing UV absorbers with biomimetic textures on the backside of the FTO substrate and a heat-extraction composite layer composed of reduced graphene oxide (rGO) and commercially available Norland Optical Adhesive (NOA) on the Au electrode, we successfully demonstrated highly efficient and stable PeSCs. The UV-absorbing layer with micro- and nano-hierarchical structures effectively cut UV light while increasing the transmittance of visible light, resulting in enhanced device stability without sacrificing the photocurrent caused by cutting the incident UV light. In addition, the introduction of a composite layer comprising rGO and NOA on the Au electrode offers superior protection, attributed to the hydrophobic nature of epoxy and the increased complexity of the oxygen or water diffusion pathway. Additionally, the outstanding thermal conductivity of rGO facilitated efficient heat dissipation through the encapsulation layer. The encapsulated PeSCs reproducibly maintained their performance during a long-term operation, even after a series of rigorous aging tests over 2 months. A UV-absorbing layer with micro-/nano hierarchical structures effectively cuts UV light while increasing the transmittance of visible light, resulting in enhanced device stability without sacrificing the photocurrent.