Search

Tin‐based perovskite solar cells (TPSCs) have received great attention due to their eco‐friendly properties and high theoretical efficiencies. However, the fast crystallization feature of tin‐based perovskites leads to poor film quality and limits the corresponding device performance. Herein, a chlorofullerene, C60Cl6, with six chlorine attached to the C60 cage, is applied to modulate the crystallization process and passivate grain boundary defects of the perovskite film. The chemical interactions between C60Cl6 and perovskite components retard the transforming process of precursors to perovskite crystals and obtain a high‐quality tin‐based perovskite film. It is also revealed that the C60Cl6 located at the surfaces and grain boundaries can not only passivate the defects but also offer a role in suturing grain boundaries to suppress the detrimental effects of water and oxygen on perovskite films, especially the oxidation of Sn2+ to Sn4+. As a result, the C60Cl6‐based device yields a remarkably improved device efficiency from 10.03% to 13.30% with enhanced stability. This work provides a new strategy to regulate the film quality and stability of TPSCs using functional fullerene materials. [ABSTRACT FROM AUTHOR]

Designing an efficient modification molecule to mitigate non-radiative recombination at the NiOx/perovskite interface and improve perovskite quality represents a challenging yet crucial endeavor for achieving high-performance inverted perovskite solar cells (PSCs). Herein, we synthesized a novel fullerene-based hole transport molecule, designated as FHTM, by integrating C60 with 12 carbazole-based moieties, and applied it as a modification molecule at the NiOx/perovskite interface. The in-situ self-doping effect, triggered by electron transfer between carbazole-based moiety and C60 within the FHTM molecule, along with the extended π conjugated moiety of carbazole groups, significantly enhances FHTM's hole mobility. Coupled with optimized energy level alignment and enhanced interface interactions, the FHTM significantly enhances hole extraction and transport in corresponding devices. Additionally, the introduced FHTM efficiently promotes homogeneous nucleation of perovskite, resulting in high-quality perovskite films. These combined improvements led to the FHTM-based PSCs yielding a champion efficiency of 25.58% (Certified: 25.04%), notably surpassing that of the control device (20.91%). Furthermore, the unencapsulated device maintained 93% of its initial efficiency after 1000 hours of maximum power point tracking under continuous one-sun illumination. This study highlights the potential of functionalized fullerenes as hole transport materials, opening up new avenues for their application in the field of PSCs., (© 2024 Wiley‐VCH GmbH.)

Tin-based perovskite solar cells (TPSCs) have received increasing attention due to their low toxicity, high theoretical efficiency, and potential applications as wearable devices. However, the inherent fast and uncontrollable crystallization process of tin-based perovskites results in high defect density in the film. Meanwhile, when fabricated into flexible devices, the prepared perovskite film exhibits inevitable brittleness and high Young's modulus, seriously weakening the mechanical stability. In this work, we design and synthesize a cross-linkable fullerene, thioctic acid functionalized C 60 fulleropyrrolidinium iodide (FTAI), which has multiple interactions with perovskite components and can finely regulate the crystallization quality of perovskite film. The obtained perovskite film shows an increased grain size and a more matched energy level with the electron transport material, effectively improving the carrier extraction efficiency. The FTAI-based rigid device achieves a champion efficiency of 14.91 % with enhanced stability. More importantly, the FTAI located at the perovskite grain boundaries could spontaneously cross-link during the perovskite annealing process, which effectively improves the conductivity and elasticity of grain boundaries, thereby giving the film excellent bending resistance. Finally, the FTAI-based wearable device yields a record efficiency of 12.35 % and displays robust bending durability, retaining about 90 % of the initial efficiency after 10,000 bending times., (© 2024 Wiley-VCH GmbH.)