中文摘要：

薄膜光电器件的能级结构直接决定了载流子的产生、分离、传输、复合和收集等微观动力学过程，从而决定了器件性能。因此准确获取器件能级结构，是深入理解器件工作机制、推动器件技术革新的重要科学依据。此专论系统地介绍了本课题组利用扫描开尔文探针显微镜（SKPM）表征薄膜光电器件如有机太阳能电池、有机．无机钙钛矿光探测器等器件中界面能级结构的工作。垂直型薄膜器件中的活性材料层被顶电极与底电极封闭，通常难以直接在器件工况下测量其中的界面能级排布，我们发展了横截面SKPM技术来解决这一难题。研究表明，界面层是调控器件能级结构、决定器件极性、提高器件性能的重要手段。本文介绍的表征技术有望在各种薄膜光电器件，诸如光伏器件、光探测器、发光二极管，尤其是各种叠层构型器件的研究中展现出广阔的应用前景。

英文摘要：

Understanding the energy band alignment across multiple layers in thin-film optoelectronic devices is extremely important because it governs elementary optoelectronic processes, such as charge carrier generation, separation, transport, recombination and collection. This monograph summarizes recent progress in visualization of energy band alignment in thin-film optoelectronic devices, such as organic solar cells （OSCs） and organic-inorganic perovskite photodetectors from our group by using scanning Kelvin probe microscopy （SKPM）. Since active layers are enclosed by the top and bottom electrodes in vertically stacked devices, it is highly challenging to study the energy band alignment under operando conditions. Thus, cross-sectional SKPM has been developed to resolve this challenge. The results demonstrated that the interlayer was one of the most important factors for adjusting energy band alignment, determining device polarity and improving device performance. The characterization methodsdescribed in this monograph are poised to be widely applied to research in various thin-film optoelectronic devices, such as photovoltaic devices, photodetectors and light-emitting diodes （LEDs）, especially those devices with tandem structures.