Bipolar Light‐Addressable Potentiometric Sensor Based on Fullerene Photosensitive Layer

• Published in: Advanced materials technologies 2021-08, Vol.6 (8), p.n/a
• Main Authors: Li, Yun‐Chong, Jiao, Bo, Zhang, Yi‐Jun, Wang, Jian, Ren, Wei, Zhang, De‐Wen, Hou, Xun, Wu, Zhao‐Xin
• Format: Article
• Language: English
• Subjects: bipolar; C 60; LAPS; pH response; photocurrent imaging
• ISSN: 2365-709X; 2365-709X
• DOI: 10.1002/admt.202001221

Light‐addressable potentiometric sensor (LAPS) is highly attractive in many sectors, including human disease detection, drug screening, and environmental monitoring. Currently, classical LAPS chips adopt inorganic semiconductors, such as silicon, as the photosensitive layer. Organic semiconductors can provide the next generation of the photosensitive layer because of their high absorption efficiency, large structural variability, eco‐friendliness, and bendability. However, no promising organic materials have been reported so far for the construction of LAPS chips. Here, the authors demonstrate the potential of fullerene (C60), a π‐conjugated carbon molecule with high n‐type conduction, as a candidate material for the photosensitive layer of LAPS. They report on a peculiar bipolar photo‐response under both reverse and forward biased conditions for C60‐based LAPS. An oxygen‐trap‐induced space‐charge mechanism is proposed to explain the unique bipolar photo‐response phenomenon. The proposed C60‐based LAPS exhibits an excellent pH sensitivity of 150 mV/pH as well as a high spatial resolution of 3.8 µm. The authors anticipate that these results will spark interest in this field and enable the replacement of the inorganic‐semiconductor photosensitive layer by organic semiconductor materials for the construction of high‐performance LAPS. Light‐addressable potentiometric sensor (LAPS) based on fullerene is reported. The fullerene‐based LAPS exhibits a unique bipolar photo‐response due to the influence of oxygen‐trap‐induced space charge. Excellent pH sensitivity of 150 mV/pH and high spatial resolution of 3.8 µm are achieved in the fullerene‐based LAPS. This work indicates a great potential of organic semiconductor material for high performance LAPS.