Reaction Dynamics of C(NH2)3SnI3 Formation from Vacuum-Deposited C(NH2)3I and SnI2 Bilayer Thin Films Investigated by In Situ Infrared Multiple-Angle Incidence-Resolved Spectroscopy

Coordination Nanosheets Stabilizing Efficient Tin-Based Perovskite Solar Cells

Tin-based perovskites, characterized by their advantageous bandgap and much lower toxicity, have emerged as a promising alternative to lead-based perovskites in solar cell applications. However, the efficiency and stability of tin-based perovskite solar cells (Sn-PSCs) are still limited by defects resulting from the easy oxidation of Sn2+ to Sn4+. Herein, an approach to enhance the optoelectronic performance of Sn-PSCs by incorporating terpyridine-zinc(II) (ZnTPY) coordination nanosheets (CONASHs), synthesized via liquid-liquid interfacial polymerization, into tin-based perovskites is delivered. Following physical fragmentation, ZnTPY CONASHs, enriched with unsaturated terpyridine groups, undergo multidentate chelation with SnI2, forming ZnTPY:SnI2 heterogeneous nuclei. This process effectively enhances the crystallization of tin-based perovskites while mitigating recombination and defect chemistry related to Sn2+ oxidation. As a result of superior crystal quality, the ZnTPY CONASHs-modified tin perovskite exhibits a longer photoluminescence lifetime. Consequently, the Sn-PSC incorporating ZnTPY complex achieves a power conversion efficiency of 11.59%, compared to 9.14% for the control device, along with improved operational stability with encapsulation. Thus, this work underscores the critical role of coordination nanosheets for regulating coordination in the precursor solution to achieve high-quality tin-based perovskite films, offering a pathway to more efficient and stable Sn-PSCs.

Quantitative Analysis of Photochemical Reactions in Pentacene Precursor Films

On-surface reactions are rapidly gaining attention as a chemical technique for synthesizing organic functional materials, such as graphene nanoribbons and molecular semiconductors. Quantitative analysis of such reactions is essential for fabricating high-quality film structures, but until our recent work using p-polarized multiple-angle incidence resolution spectrometry (pMAIRS), no analytical technique is available to quantify the reaction rate. In the present study, the pMAIRS technique is employed to analyze the photochemical reaction from 6,13-dihydro-6,13-ethanopentacene-15,16-dione to pentacene in thin films. The spectral analysis on a pMAIRS principle readily reveals the photoconversion rate accurately without other complicated calculations. Thus, this study underlines that the pMAIRS technique is a powerful tool for quantitative analysis of on-surface reactions, as well as molecular orientation.