{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T07:57:30Z","timestamp":1761897450819,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,8]],"date-time":"2021-01-08T00:00:00Z","timestamp":1610064000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Foundation of Korea (NRF)","award":["5199990714521"],"award-info":[{"award-number":["5199990714521"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A fast-response colorimetric ultraviolet-C (UVC) sensor was demonstrated using a gallium oxide (Ga2O3) photocatalyst with small amounts of triethanolamine (TEOA) in methylene blue (MB) solutions and a conventional RGB photodetector. The color of the MB solution changed upon UVC exposure, which was observed using an in situ RGB photodetector. Thereby, the UVC exposure was numerically quantified as an MB reduction rate with the R value of the photodetector, which was linearly correlated with the measured spectral absorbance using a UV-Vis spectrophotometer. Small amount of TEOA in the MB solution served as a hole scavenger, which resulted in fast MB color changes due to the enhanced charge separation. However, excessive TEOA over 5 wt.% started to block the catalytical active site on the surface of Ga2O3, prohibiting the chemical reaction between the MB molecules and catalytic sites. The proposed colorimetric UVC sensor could monitor the detrimental UVC radiation with high responsivity at a low cost.<\/jats:p>","DOI":"10.3390\/s21020387","type":"journal-article","created":{"date-parts":[[2021,1,10]],"date-time":"2021-01-10T23:03:42Z","timestamp":1610319822000},"page":"387","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Fast-Response Colorimetric UVC Sensor Made of a Ga2O3 Photocatalyst with a Hole Scavenger"],"prefix":"10.3390","volume":"21","author":[{"given":"Heejoong","family":"Ryou","sequence":"first","affiliation":[{"name":"Department of Materials Engineering, Korea Aerospace University, Goyang 10540, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1821-2186","authenticated-orcid":false,"given":"Sunjae","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Materials Engineering, Korea Aerospace University, Goyang 10540, Korea"},{"name":"Smart Drone Convergence, Korea Aerospace University, Goyang 10540, Korea"}]},{"given":"Myunghun","family":"Shin","sequence":"additional","affiliation":[{"name":"School of Electronics and Information Engineering, Korea Aerospace University, Goyang 10540, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4211-4113","authenticated-orcid":false,"given":"Junsang","family":"Cho","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Duksung Women\u2019s University, Seoul 01369, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0060-9348","authenticated-orcid":false,"given":"Wan Sik","family":"Hwang","sequence":"additional","affiliation":[{"name":"Department of Materials Engineering, Korea Aerospace University, Goyang 10540, Korea"},{"name":"Smart Drone Convergence, Korea Aerospace University, Goyang 10540, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.ijfoodmicro.2008.11.020","article-title":"Inactivation of food spoilage fungi by ultra violet (UVC) irradiation","volume":"129","author":"Begum","year":"2009","journal-title":"Int. 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