Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (10): 1934-1943.doi: 10.3866/PKU.WHXB201715185

• FEATURE ARTICLE • Previous Articles     Next Articles

Visualization of Energy Band Alignment in Thin-Film Optoelectronic Devices with Scanning Kelvin Probe Microscopy

Ji-Chong LIU1,2,Feng TANG1,2,Feng-Ye YE1,3,Qi CHEN1,*(),Li-Wei CHEN1,*()   

  1. 1 i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu Province, P. R. China
    2 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
    3 Department of Chemistry, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2017-04-13 Published:2017-07-17
  • Contact: Qi CHEN,Li-Wei CHEN;
  • Supported by:
    the National Natural Science Foundation of China(21625304);the National Natural Science Foundation of China(51473184);the National Natural Science Foundation of China(11504408);Ministry of Science and Technology of China(2016YFA0200703);the CAS Research Equipment Development Program(YZ201654)


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 methods described 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.

Key words: Scanning Kelvin probe microscopy, Energy band alignment, Cross-section, Interlayer Organic solar cells, Organic-inorganic perovskite photodetectors