Physical Passivation of Grain Boundaries and Defects in Perovskite Solar Cells by an Isolating Thin Polymer

Abstract

Passivation and interlayer engineering are important approaches to increase the efficiency and stability of perovskite solar cells. Thin insulating dielectric films at the interface between the perovskite and the charge carrier transport layers have been suggested to passivate surface defects. Here, we analyze the effect of depositing poly­(methyl methacrylate) (PMMA) from a very low-concentration solution. Spatial- and time-resolved photoluminescence and atomic force microscopy analyses of samples with diverse morphologies demonstrate the preferential deposition of PMMA in topographic depressions of the perovskite layer, such as grain and domain boundaries. This treatment results in an increase in the fill factor of more than 4% and an absolute efficiency boost exceeding 1%, with a maximum efficiency of 20.4%. Based on these results, we propose a physical isolation mechanism rather than a chemical passivation of perovskite defects, which explains not only the data of this study but also most results found in earlier works.

Towards high tin‐based halide organic‐inorganic perovskite photovoltaic cells efficiency improvement: SCAPS 1D modeling

“…That means, they can exist as point defects or grain boundaries (GBs). 10,28,29 Investigating the effects of these GBs on the overall device performance remain up until now, a hot topic in the way of optimizing solar cells architectures. 30 Ground boundaries According to experimental results and previous work, nature and density of DS in PSCs are extremely sensitive to the film deposition conditions.…”

“…Ochoa‐Martinez et al reports in a very recent work 28 that, despite all manufacturing efforts, all deposition methods result in perovskite films with variable degrees of defects that limit the device performance. Their existence in the structure is indeed unavoidable.…”

Investigation of the exciton relaxation processes in poly(9,9-dioctylfluorene-co-benzothiadiazole):CsPbI1.5Br1.5 nanocrystal hybrid polymer–perovskite nanocrystal blend

“…The disappearance of the NCs PL intensity increase above 230 K is consistent with the aggregation reduction, due to NCs dispersion in the polymer matrix, and with the passivation of surface states from the polymer. 51 …”

Enhanced Thermal Stability of Planar Perovskite Solar Cells Through Triphenylphosphine Interface Passivation

“…[20][21][22][23] Hence, it is unsurprising that defects present in PSCs wield significant influence over key photovoltaic performance metrics such as short-circuit current density (J sc ), open-circuit voltage (V oc ), fill factor (FF), and PCE. [24][25][26] Interfacial engineering between the perovskite absorber and charge transport layers has been widely successful in enhancing the performance and durability of PSCs. [27][28][29] This is due to the tendency for defect or impurity formation at the interfaces, which arises from the sudden change in the lattice structure and crystal orientation.…”

“…Furthermore, these defects can act as ion migration or moisture/oxygen diffusion channels, thereby promoting perovskite degradation and device instability [20–23] . Hence, it is unsurprising that defects present in PSCs wield significant influence over key photovoltaic performance metrics such as short‐circuit current density ( J sc ), open‐circuit voltage ( V oc ), fill factor (FF), and PCE [24–26] …”