[论文解读] SAM Molecular Stacking with Heterogeneous Orientationfor High-Performance Perovskite Photovoltaics

Lei Huang, Kai-Li Wang+12 more|arXiv (Cornell University)|Mar 23, 2026

Perovskite Materials and Applications被引用 0

一句话总结

热蒸发自组装单层膜（eSAM）形成厚度梯度取向，生成垂直到水平的堆积梯度，从而实现分级能障并改善空穴传输，提升钙钛矿光伏的高效性能。

ABSTRACT

This study demonstrates that thermal-evaporated SAM (eSAM) films, particularly in a thick configuration, spontaneously adopt a heterogeneous molecular orientation, forming a vertical-to-horizontal gradient in molecular packing. This unique architecture establishes a graded energy barrier, which is shown to facilitate more efficient hole transport compared with the single energy barrier presented by conventional thin SAMs. In conclusion, while solution-processed SAMs present formidable scalability challenges, the thermal evaporation of SAMs offers a viable pathway toward industrial-scale fabrication. The strategy of employing thick eSAM films with gradient molecular packing not only circumvents the uniformity issues of solution methods but also introduces a superior structure for charge transport, positioning it as a promising enabler for the commercialization of high-efficiency perovskite photovoltaics. The inability to achieve uniform hole transport with solution-processed self-assembled monolayers (SAMs) constitutes a fundamental bottleneck for scaling perovskite photovoltaics. Herein, we demonstrate that thermal-evaporated SAMs (eSAMs) overcome this limitation by enabling precise thickness control. Crucially, a thickened eSAM spontaneously forms a vertical-to-horizontal gradient in molecular orientation, which creates a descending energy barrier that directionally facilitates hole transport. This tailored interface also ensures excellent surface coverage and directs the growth of high-quality perovskite films. Consequently, the resultant photovoltaic devices set new benchmarks, delivering impressive power conversion efficiencies (PCEs) of 21.46% (small-area, 0.108 cm2) and 19.38% (large-area module, 15.52 cm2) for fully vacuum-evaporated devices, while also setting an impressive PCE of 23.67% for eSAM-based devices with solution-processed perovskites.

研究动机与目标

• 解决用于大规模钙钛矿光伏的溶液加工SAMs的 uniformity 瓶颈问题。
• 证明厚厚的热蒸发自组装单层膜会自发在分子取向上形成垂直到水平的梯度。
• 显示梯度能障有利于定向空穴传输并改善界面处的薄膜质量。
• 在完全真空蒸发的器件中实现高功率转换效率，并在基于 eSAM 的溶液加工器件中实现具有竞争力的性能。
• 提出 eSAM 作为实现高效钙钛矿光伏工业化制备的可扩展途径。

提出的方法

• 热蒸发自组装单层膜（eSAMs）形成厚的界面层。
• 表征厚厚的 eSAM 薄膜中从垂直到水平的分子取向梯度。
• 评估由此产生的能障轮廓及其对界面处空穴传输的影响。
• 在分级的 eSAM界面上生长高质量的钙钛矿薄膜，以最大化表面覆盖和器件性能。
• 在真空和溶液加工条件下制备并测试小面积和大面积的钙钛矿光伏器件。

实验结果

研究问题

• RQ1 厚厚的 eSAM 是否会自发形成分子取向的垂直到水平梯度？
• RQ2 梯度能障是否增强相较于传统薄 SAM 的定向空穴传输？
• RQ3 厚 eSAM 界面是否能实现高质量的钙钛矿生长并在真空蒸发和溶液加工配置中实现改进的器件性能？
• RQ4 对于完全真空蒸发的器件和基于 eSAM 的溶液加工器件，能够达到的 PCE 是多少？
• RQ5 热蒸发 SAM 是否是实现高效钙钛矿光伏产业化制备的可扩展路径？

主要发现

• 厚 eSAM 薄膜自发地呈现分子取向的垂直到水平梯度。
• 该梯度形成一个降序的能障，定向促进空穴传输。
• 分级的界面结构实现了卓越的表面覆盖与高质量的钙钛矿生长。
• 完全真空蒸发的 eSAM 器件在小面积 (0.108 cm2) 中达到 21.46% 的 PCE，在大面积模组 (15.52 cm2) 中达到 19.38% 的 PCE。
• 基于 eSAM 的溶液加工钙钛矿器件达到 23.67% 的 PCE。