Revealing the Mechanism behind the Catastrophic Failure of n‐i‐p Type Perovskite Solar Cells under Operating Conditions and How to Suppress It

Abstract

The n‐i‐p type perovskite solar cells suffer unpredictable catastrophic failure under operation, which is a barrier for their commercialization. The fluorescence enhancement at Ag electrode edge and performance recovery after cutting the Ag electrode edge off prove that the shunting position is mainly located at the edge of device. Surface morphology and elemental analyses prove the corrosion of the Ag electrode and the diffusion of Ag+ ions on the edge for aged cells. Moreover, much condensed and larger Ag clusters are formed on the MoO3 layer. Such a contrast is also observed while comparing the central and the edge of the Ag/Spiro‐OMeTAD film. Hence, the catastrophic failure mechanism can be concluded as photon‐induced decomposition of the perovskite film and release reactive iodide species, which diffuse and react with the loose Ag clusters on the edge of the cell. The corrosion of the Ag electrode and the migration of Ag+ ions into Spiro‐OMeTAD and perovskite films lead to the forming of conducting filament that shunts the cell. The more condensed Ag cluster on the MoO3 surface as well as the blocking of holes within the Spiro‐OMeTAD/MoO3 interface successfully prevent the oxidation of Ag electrode and suppress the catastrophic failure.

Recent advances in the interfacial engineering of organic–inorganic hybrid perovskite solar cells: a materials perspective

“…Currently, the most commonly used metal oxide transparent conductive films for the bottom electrode of PSCs are indium-doped tin oxide (ITO) and fluorine-doped tin oxide (FTO), etc., whose photovoltaic properties are closely related to the film thickness and film quality. 49,50 Among them, ITO is commonly used as the bottom electrode for planar structured PSCs. Compared with ITO, FTO has a lower light transmission rate due to its larger thickness, but it is more suitable as a substrate for interfacial layers that require high-temperature heating, such as TiO 2 , due to its corrosion resistance and hightemperature tolerance, and is therefore widely used as the bottom electrode for mesoporous structured PSCs.…”

Lamination methods for the fabrication of perovskite and organic photovoltaics

“…[135][136][137] However, the Ag NPs inks require sintering at high temperatures to provide better conductivity, which most of the time leads to silver diffusing into the layers beneath and subsequently damaging the perovskite structure. [138][139][140] To address this challenge, Trinh et al spin-coated the Ag NPs ink onto a PET substrate and annealing, followed by spin-coating the PEDOT:PSS/D-sorbitol solution on top as the first stack. Then, they laminated the first stack onto the second stack consisting of FTO/c-TiO 2 /m-TiO 2 /CH 3 NH 3 PbI 3 /Spiro-MeOTAD layers at 120 1C for 10 min, followed by finger pressure pressing to complete the device.…”

“…Therefore, it is quite necessary to introduce better device fabrication methods that are more compatible with scalable R2R processes. 90,91,[139][140][141][142][143] The lamination of pre-deposited layers on different stacks has been introduced as a promising method to fabricate highly efficient and stable OPVs. Similar to the PSCs section, here, we classified the laminated OPVs based on laminating chargetransporting layers (CTLs) and/or both CTLs and back contact electrodes.…”

Stabilization Techniques of Lead Halide Perovskite for Photovoltaic Applications

“…As discussed above, different barrier materials of cross‐linked polymer, [ 187 ] metal, [ 203 ] metal oxides, [ 204 ] carbon quantum dots, [ 205 ] and oxo‐functionalized graphene [ 206 ] have been applied to hindering the corrosion of electrodes, restrict the ion migration, and prolong the lifetime of the devices. Among them, metals like Cr suffer from work function mismatch, and metal oxides have the problem of deposition cost.…”