Surface Reconstruction for Efficient and Stable Monolithic Perovskite/Silicon Tandem Solar Cells with Greatly Suppressed Residual Strain

Abstract

Despite the swift rise in power conversion efficiency (PCE) to more than 32%, the instability of perovskite/silicon tandem solar cells is still one of the key obstacles to practical application and is closely related to the residual strain of perovskite films. Herein, a simple surface reconstruction strategy is developed to achieve a global incorporation of butylammonium cations at both surface and bulk grain boundaries by post‐treating perovskite films with a mixture of N,N‐dimethylformamide and n‐butylammonium iodide in isopropanol solvent, enabling strain‐free perovskite films with simultaneously reduced defect density, suppressed ion migration, and improved energy level alignment. As a result, the corresponding single‐junction perovskite solar cells yield a champion PCE of 21.8%, while maintaining 100% and 81% of their initial PCEs without encapsulation after storage for over 2500 h in N2 and 1800 h in air, respectively. Remarkably, a certified stabilized PCE of 29.0% for the monolithic perovskite/silicon tandems based on tunnel oxide passivated contacts is further demonstrated. The unencapsulated tandem device retains 86.6% of its initial performance after 306 h at maximum power point (MPP) tracking under continuous xenon‐lamp illumination without filtering ultraviolet light (in air, 20–35 °C, 25–75%RH, most often ≈60%RH).

Dual‐Interface Modulation with Covalent Organic Framework Enables Efficient and Durable Perovskite Solar Cells

“…Specifically, the buried HS-COFs film shows a positive value (0.154) and the control film exhibits a negative value (−0.202), demonstrating that the tensile strain is completely turned into compressive strain. [48] On account of the aforementioned results, a schematic illustra-tion of the strain release and defect passivation mechanism is proposed and displayed in Figure 3d. The lattice strain release in HS-COFs buried films may be attributed to surface defect (lattice mismatch) passivation and the change of thermal expansion coefficient between the perovskite and TiO 2 layers.…”

Recent Progress of Wide Bandgap Perovskites towards Two-Terminal Perovskite/Silicon Tandem Solar Cells

“…Copyright © 2023, Elsevier. ( b ) Schematic diagram and cross-sectional scanning electron microscopy (SEM) image of a texture-structured silicon perovskite tandem solar cell [ 103 ]. Copyright © 2023, John Wiley and Sons.…”

Perovskite/Silicon Tandem Solar Cells: Insights and Outlooks

“…145 The I-rich region would become the recombination center for photogenerated carriers, leading to photoluminescence (PL) redshift and reduced V OC of the PSTSCs. 154 Although additional Cs can be introduced into FA film to minimize the Br content to improve the light stability by helping to alleviate micro-strain in the lattice and increase the dynamic barriers for ion migration to mitigate the phase segregation, 71 the V OC deficits and photostability still need further improvement.…”