Engineering Chalcogenide-Containing Spacers: Modulating Internal Interactions for Enhanced Performance and Stability in Ruddlesden–Popper Perovskite Devices

Two-dimensional
(2D) Ruddlesden–Popper (RP) halide
perovskites
are promising for optoelectronic applications due to their enhanced
stability compared to 3D versions. However, their practical application
is still hindered by the inherent instability arising from weak interactions
between adjacent organic layers. To address this challenge, we engineered
2D RP perovskites using four organic spacers: 3-thiophene-methylammonium
(3-TMA) and 3-furan-methylammonium (3-FMA), with 2-thiophene-methylammonium
(2-TMA) and 2-furan-methylammonium (2-FMA) as controls. Our findings
highlight that the heteroatom type (S vs O) and spacer regiochemistry
significantly influence interaction strength. Thiophene-based spacers
bond more robustly to inorganic layers than furan-based ones. Notably,
shifting the thiophene spacer configuration from 2-TMA to 3-TMA markedly
strengthens interactions between organic layers, improving RP perovskite
stability under ambient and thermal conditions. Utilizing the substantial
dipole moment of the optimized 3-TMA spacer, we developed an enhanced
performance perovskite photodetector with a responsivity of 153 mA/W
and detectivity of 1.7 × 1010 Jones. This study offers
insights into RP perovskite stability and guides the design of durable
perovskite devices through strategic spacer engineering.

二维（2D）吕德斯登-波珀（Ruddlesden–Popper，RP）卤化物钙钛矿相较于三维钙钛矿具有更优异的稳定性，因此在光电子学应用中展现出巨大潜力。然而，相邻有机层间相互作用较弱所引发的本征不稳定性，仍制约了其实际应用。为解决这一难题，本研究通过四种有机间隔基构建二维RP钙钛矿：以3-噻吩甲胺（3-thiophene-methylammonium，3-TMA）与3-呋喃甲胺（3-furan-methylammonium，3-FMA）为研究样本，以2-噻吩甲胺（2-thiophene-methylammonium，2-TMA）与2-呋喃甲胺（2-furan-methylammonium，2-FMA）作为对照。研究结果表明，杂原子种类（硫S与氧O）以及间隔基的区域化学构型，对层间相互作用强度具有显著影响。噻吩类间隔基与无机层的结合稳定性优于呋喃类间隔基。值得注意的是，将噻吩类间隔基的构型从2-TMA调整为3-TMA，可显著增强有机层间的相互作用，进而提升RP钙钛矿在大气环境与热应力条件下的稳定性。依托优化后的3-TMA间隔基所具备的大偶极矩，我们制备了性能提升的钙钛矿光电探测器，其响应度达153 mA/W，探测率为1.7×10^10 琼斯（Jones）。本研究为RP钙钛矿的稳定性调控提供了新的见解，并通过合理的间隔基工程设计，为耐用型钙钛矿器件的研发提供了指导方向。