Lee, Donghun Park, Haeli Han, Soo Deok Kim, Su Han Huh, Woong Lee, Jae Yoon Kim, Yoon Seok Park, Myung Jin Park, Won Il Kang, Chong-Yun Lee, Chul-Ho 2024-01-19T21:02:12Z 2024-01-19T21:02:12Z 2021-09-02 2019-01-11 1613-6810 https://pubs.kist.re.kr/handle/201004/120469 Ultralow power chemical sensing is essential toward realizing the Internet of Things. However, electrically driven sensors must consume power to generate an electrical readout. Here, a different class of self-powered chemical sensing platform based on unconventional photovoltaic heterojunctions consisting of a top graphene (Gr) layer in contact with underlying photoactive semiconductors including bulk silicon and layered transition metal dichalcogenides is proposed. Owing to the chemically tunable electrochemical potential of Gr, the built-in potential at the junction is effectively modulated by absorbed gas molecules in a predictable manner depending on their redox characteristics. Such ability distinctive from bulk photovoltaic counterparts enables photovoltaic-driven chemical sensing without electric power consumption. Furthermore, it is demonstrated that the hydrogen (H-2) sensing properties are independent of the light intensity, but sensitive to the gas concentration down to the 1 ppm level at room temperature. These results present an innovative strategy to realize extremely energy-efficient sensors, providing an important advancement for future ubiquitous sensing. English WILEY-V C H VERLAG GMBH SOLAR-CELLS SENSOR VOLTAGE ARRAYS Self-Powered Chemical Sensing Driven by Graphene-Based Photovoltaic Heterojunctions with Chemically Tunable Built-In Potentials Article 10.1002/smll.201804303 1 SMALL, v.15, no.2 SMALL 15 2 scie scopus 000455545800010 2-s2.0-85058237438 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article SOLAR-CELLS SENSOR VOLTAGE ARRAYS 2D materials chemical sensors graphene heterostructures photovoltaic