Film-Depth-Dependent Light Absorption Spectroscopy of Organic Thin Films

作者：Laju Bu, Xianqiang Xie, Zichao Shen, Guanghao Lu · 发表于：Accounts of Materials Research · 年份：2025 · DOI：10.1021/accountsmr.5c00059 · 被引用次数：14 · 研究领域：Organic Electronics and Photovoltaics、Conducting polymers and applications、Thin-Film Transistor Technologies

Conspectus Organic thin films, with thickness ranging from tens to hundreds of nanometers, are foundational to organic electronic devices. Yet, vertical phase separation during film deposition and postprocessing, along with the corresponding variations in crystallinity and photoelectric properties along the film-depth direction, critically influences device performance. Traditional characterization methods, such as cross-sectional electron microscopy, neutron reflectivity, or incremental etching coupled with mass spectrometry, suffer from key limitations: sample-destructive analysis, high-cost or inaccessible instrument, or an inability to directly probe depth-dependent optoelectronic behaviors inside the film. These shortcomings hinder the optimal design of high-performance devices. To overcome these challenges, we developed film-depth-dependent light absorption spectroscopy (FLAS), an innovative and accessible technique combining soft plasma etching with UV–vis spectroscopy. FLAS achieves ∼1 nm depth resolution of vertical phase separation, enables seminondestructive profiling of vertical properties, and directly correlates structural insights with device optimization. Over the past decade, FLAS has been widely applied for the depth-dependent analysis of organic films, and its effectiveness in elucidating the relationship between favorable film structure and high device performance has been validated. In this Account, we focus on the mechanisms and device applications of FL...