Improving the Long-Term Stability of Perovskite Solar Cells with a Porous Al₂O₃ Buffer Layer

Abstract

Hybrid perovskites represent a new paradigm for photovoltaics, which have the potential to overcome the performance limits of current technologies and achieve low cost and high versatility. However, an efficiency drop is often observed within the first few hundred hours of device operation, which could become an important issue. Here, we demonstrate that the electrode's metal migrating through the hole transporting material (HTM) layer and eventually contacting the perovskite is in part responsible for this early device degradation. We show that depositing the HTM within an insulating mesoporous "buffer layer" comprised of Al2O3 nanoparticles prevents the metal electrode migration while allowing for precise control of the HTM thickness. This enables an improvement in the solar cell fill factor and prevents degradation of the device after 350 h of operation.

High-performance ultraviolet-visible tunable perovskite photodetector based on solar cell structure

“…In reports by Lin et al [18], their photodetectors possessed a high detectivity beyond 10 12 Jones and a PCE of more than 12%. A self-powered, ultraviolet-visible (UV-vis) perovskite photodetector based on TiO2 nanorods was also reported with a PCE of 6.95% and the device exhibited good UV-visible photoresponse characteristics with a responsivity at zero bias reaching approximately 0.26 and 0.85 A W −1 at 364 and 494 nm, respectively [19].…”

“…Perovskite materials have many advantages, including a direct band gap with a large absorption coefficient, high electrical mobility, long charge carrier lifetime, and long diffusion length [6][7][8][9][10][11]. In perovskite solar cells, some scaffold materials, such as Al2O3, TiO2, and ZnO, have been widely used [4,[12][13][14]. Of these, ZnO nanostructures have been extensively investigated mainly because they are environmentally friendly and cheap with a wide bandgap of 3.3 eV at room temperature, and have a large exciton binding energy of 60 meV [15][16][17].…”

A stable lead halide perovskite nanocrystals protected by PMMA

“…The other method to stabilize HOIPs against water is covering them with waterresistant materials including mesoporous inorganic matrices [19][20][21][22] or organic small molecules [23]. Most recently, microencapsulation of polymer was found to offer a barrier to moisture [24][25][26][27], but the methods tend to generate lead ions at the surface and the easily exfoliated coating due to the weak chemical bonds [28].…”

Research Update: Strategies for improving the stability of perovskite solar cells

“…Several such barrier materials have been explored and shown to reduce moisture ingress and improve stability in a non-dry environment. [48][49][50][51][52] Using atomic layer deposition (ALD) as a technique to deposit an ultrathin layer of Al 2 O 3 between the perovskite and spiro-OMeTAD, the stability of a device kept at RH 50% without illumination for 24 days could be improved and its performance was reported to still be at 90% of the initial value. 48 Guarnera et al showed that a simply spin-coated layer of alumina nanoparticles at the interface of the perovskite absorber and spiro-OMeTAD improves performance and stability.…”