Hyperbranched polymer functionalized flexible perovskite solar cells with mechanical robustness and reduced lead leakage

Abstract

Perovskite solar cells (PSCs) are multilayer structures. The interface between electron transport layer and perovskite is the mechanical weakest point in flexible PSCs due to its low fracture energy. Herein, we develop a highly adhesive polyamide-amine-based hyperbranched polymers to reinforce the interface. The interface fracture energy is improved from 1.08 to 2.13 J·m−2 by the hyperbranched polymers with adhesive groups and dynamic hydrogen bond networks. The polymer functionalized perovskite solar cells achieve superior power conversion efficiencies of 25.05% and 23.86% for rigid and flexible devices, respectively. Furthermore, the hyperbranched polymer contains abundant intramolecular cavities that can capture Pb2+. Pb leakage after solar cell damage is effectively suppressed. Our findings provide insights on designing adhesive interface layers towards high-efficiency, mechanical-stable and environment-friendly flexible perovskite solar cells.

Influence of Hole Transport Layers on Buried Interface in Wide-Bandgap Perovskite Phase Segregation

“…We investigated phase stability and performance differences between wide-bandgap perovskite films grown on Me-4PACz and PTAA substrates with the perovskite materials composed of FA 0.8 Cs 0.2 PbI 1.8 Br 1.2 . Initially, the photoluminescence (PL) peak for films on PTAA substrates was centered at 695 nm, corresponding to a bandgap of 1.78 eV, which aligns with the literature findings [41]. Upon subjecting the samples to 600 s of continuous 532 nm laser illumination, a slight redshift to 705 nm was observed, indicating the emergence of iodine-rich perovskite with lower bandgaps, while the bromine-rich perovskite remained relatively stable (Figure 1a).…”

“…The perovskite film possesses a bandgap of 1.78 eV and consists of approximately 40% bromine and 60% iodine. We incorporated a 10% excess of lead iodine into the precursor, following a preparation method similar to that outlined in refs [ 41 , 42 ]. The precursor solution (1.2 M) was formulated from four precursors dissolved in a mixed solvent of DMF and DMSO with a volume ratio of 4:1.…”

23.81%-Efficiency Flexible Inverted Perovskite Solar Cells with Enhanced Stability and Flexibility via a Lewis Base Passivation

“…Flexible inverted perovskite solar cells (PSCs) have become a popular research field due to their advantages, including high power conversion efficiency (PCE), potential for high stability, good flexibility, and lightweight properties that are very suitable for wearable and portable photovoltaic applications. − The inverted PSCs also have the striking advantages of their low-temperature processing and compatibility with large-scale and tandem solar-cell integration. , To date, the record-high PCE of the flexible inverted PSCs has reached 24.08% through incorporating additives into perovskite precursors . The ultimate objective of the flexible PSC fields is to develop highly efficient, stable, and mechanically flexible photovoltaics.…”

Surface Reconstruction via Molten Chloride Salt for Efficient and Stable Perovskite Solar Cells

“…Therefore, intense research has been devoted toward minimizing grain boundaries and structural defects and enhancing the structural integrity of PVK films via compositional, , morphological, , and interfacial engineering. , Among the developed strategies, a solution-based surface passivation approach has been widely used to alleviate surface imperfections at the stage of PVK preparation. A variety of defect passivators, including inorganic salts, , alkylammonium halogen salts, − Lewis acids and bases, − and polymers, , have proven to be effective in minimizing surface imperfections, thereby promoting the efficiency and stability of PSCs. Given that the post-treatment mainly occurs at the surface, the regulation in the bulk PVK film is generally limited due to the poor diffusivity of the molecular or ionic passivators attached with bulky molecular skeletons.…”