{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T03:59:30Z","timestamp":1777867170330,"version":"3.51.4"},"reference-count":26,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2015,12,10]],"date-time":"2015-12-10T00:00:00Z","timestamp":1449705600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"the National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11004021, 11274057, 11474046"],"award-info":[{"award-number":["11004021, 11274057, 11474046"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100005047","name":"Natural Science Foundation of Liaoning Province","doi-asserted-by":"publisher","award":["2013020089"],"award-info":[{"award-number":["2013020089"]}],"id":[{"id":"10.13039\/501100005047","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Program for Liaoning Excellent Talents in University"},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["DC201502080202, DC201502080406"],"award-info":[{"award-number":["DC201502080202, DC201502080406"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Upconversion luminescence properties from the emissions of Stark sublevels of Er3+ were investigated in Er3+-Yb3+-Mo6+-codoped TiO2 phosphors in this study. According to the energy levels split from Er3+, green and red emissions from the transitions of four coupled energy levels, 2H11\/2(I)\/2H11\/2(II), 4S3\/2(I)\/4S3\/2(II), 4F9\/2(I)\/4F9\/2(II), and 2H11\/2(I) + 2H11\/2(II)\/4S3\/2(I) + 4S3\/2(II), were observed under 976 nm laser diode excitation. By utilizing the fluorescence intensity ratio (FIR) technique, temperature-dependent upconversion emissions from these four coupled energy levels were analyzed at length. The optical temperature-sensing behaviors of sensing sensitivity, measurement error, and operating temperature for the four coupled energy levels are discussed, all of which are closely related to the energy gap of the coupled energy levels, FIR value, and luminescence intensity. Experimental results suggest that Er3+-Yb3+-Mo6+-codoped TiO2 phosphor with four pairs of energy levels coupled by Stark sublevels provides a new and effective route to realize multiple optical temperature-sensing through a wide range of temperatures in an independent system.<\/jats:p>","DOI":"10.3390\/s151229839","type":"journal-article","created":{"date-parts":[[2015,12,14]],"date-time":"2015-12-14T02:57:29Z","timestamp":1450061849000},"page":"30981-30990","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":60,"title":["Multiple Temperature-Sensing Behavior of Green and Red Upconversion Emissions from Stark Sublevels of Er3+"],"prefix":"10.3390","volume":"15","author":[{"given":"Baosheng","family":"Cao","sequence":"first","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinlei","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xuehan","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yangyang","family":"He","sequence":"additional","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhiqing","family":"Feng","sequence":"additional","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bin","family":"Dong","sequence":"additional","affiliation":[{"name":"School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,12,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4743","DOI":"10.1063\/1.1606526","article-title":"Fluorescence intensity ratio technique for optical fiber point temperature sensing","volume":"94","author":"Wade","year":"2003","journal-title":"J. Appl. Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4743","DOI":"10.1039\/C4CS00392F","article-title":"An overview of nanoparticles commonly used in fluorescent bioimaging","volume":"44","author":"Wolfbeis","year":"2015","journal-title":"Chem. Soc. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3180","DOI":"10.1063\/1.1387250","article-title":"Effect of strain on temperature measurements using the fluorescence intensity ratio technique (with Nd3+- and Yb3+-doped silica fibers)","volume":"72","author":"Wade","year":"2001","journal-title":"Rev. Sci. Instrum."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5673","DOI":"10.3390\/s8095673","article-title":"Thermographic phosphors for high temperature measurements: Principles, current state of the art and recent applications","volume":"8","author":"Khalid","year":"2008","journal-title":"Sensors"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3524","DOI":"10.1063\/1.1578706","article-title":"Effects of high-temperature heat treatment on Nd3+-doped optical fibers for use in fluorescence intensity ratio based temperature sensing","volume":"74","author":"Sidiroglou","year":"2003","journal-title":"Rev. Sci. Instrum."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Schartner, E.P., and Monro, T.M. (2014). Fibre tip sensors for localised temperature sensing based on rare earth-doped glass coatings. Sensors, 21693\u201321701.","DOI":"10.3390\/s141121693"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"331","DOI":"10.7150\/thno.5305","article-title":"Sensing using rare-earth-doped upconversion nanoparticles","volume":"3","author":"Hao","year":"2013","journal-title":"Theranostics"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1096","DOI":"10.1016\/j.snb.2013.07.094","article-title":"Optical temperature sensing through the upconversion luminescence from Ho3+\/Yb3+ cdoped CaWO4","volume":"188","author":"Xu","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/j.matchemphys.2013.07.025","article-title":"Investigation of near-infrared-to-ultraviolet upconversion luminescence of Tm3+ doped NaYF4 phosphors by Yb3+ codoping","volume":"142","author":"Cao","year":"2013","journal-title":"Mater. Chem. Phys."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Dong, B., Liu, D.P., Wang, X.J., Yang, T., Miao, S.M., and Li, C.R. (2007). Optical thermometry through infrared excited green upconversion emissions in Er3+-Yb3+ codoped Al2O3. Appl. Phys. Lett., 90.","DOI":"10.1063\/1.2735955"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"15119","DOI":"10.1021\/jp0686689","article-title":"Effect of annealing on upconversion luminescence of ZnO:Er3+ nanocrystals and high thermal sensitivity","volume":"111","author":"Wang","year":"2007","journal-title":"J. Phys. Chem. C"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.jlumin.2012.10.031","article-title":"Upconversion properties of Er3+-Yb3+: NaYF4 phosphors with a wide range of Yb3+ concentration","volume":"135","author":"Cao","year":"2013","journal-title":"J. Lumin."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"3254","DOI":"10.1021\/nn100244a","article-title":"Temperature sensing using fluorescent nanothermometers","volume":"4","author":"Vetrone","year":"2010","journal-title":"ACS Nano"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"9899","DOI":"10.1166\/jnn.2011.5236","article-title":"Optical high temperature sensor based on enhanced green upconversion emissions in Er3+-Yb3+-Li+ codoped TiO2 powders","volume":"11","author":"Cao","year":"2011","journal-title":"J. Nanosci. Nanotechnol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"34999","DOI":"10.1039\/C4RA15891A","article-title":"Stark sublevels in Tm3+-Yb3+ codoped Na2Y2B2O7 nanophosphor for multifunctional applications","volume":"5","author":"Soni","year":"2015","journal-title":"RSC Adv."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1406","DOI":"10.1016\/j.saa.2007.02.017","article-title":"Temperature sensing behaviour of the stark sublevels","volume":"68","author":"Rai","year":"2007","journal-title":"Spectrochim. Acta A"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1117\/12.221711","article-title":"Thermal variation of absorption in Yb3+-doped silica fiber for high-temperature sensor applications","volume":"2510","author":"Baxter","year":"1995","journal-title":"Proc. SPIE"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Feng, Z.J., Zhang, X.S., Zhou, Y.L., Ling, Z., Li, M.Z., Sun, J., and Li, L. (2013). Influence of temperature on the transition of Stark sublevels of Er3+ doped ZBLAN glass. Acta Opt. Sin., 33.","DOI":"10.3788\/AOS201333.0816001"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1016\/j.tsf.2013.10.054","article-title":"Structure and upconversion luminescence properties of Er3+-Mo6+ codoped Yb2Ti2O7 films","volume":"550","author":"Cao","year":"2014","journal-title":"Thin Solid Films"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1987","DOI":"10.1002\/adma.201200431","article-title":"Temperature Sensing and in Vivo Imaging by Molybdenum Sensitized Visible Upconversion Luminescence of Rare-Earth Oxides","volume":"24","author":"Dong","year":"2012","journal-title":"Adv. Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.snb.2011.05.018","article-title":"Optical temperature sensing behavior of enhanced green upconversion emissions from Er-Mo:Yb2Ti2O7 nanophosphor","volume":"159","author":"Cao","year":"2011","journal-title":"Sens. Actuators B Chem."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Cao, B.S., Wu, J.L., Wang, X.H., He, Y.Y., Feng, Z.Q., Dong, B., and Rino, L. (2015). Multiple temperature effects on up-conversion fluorescences of Er3+-Yb3+-Mo6+ codoped TiO2 and high thermal sensitivity. AIP Adv., 5.","DOI":"10.1063\/1.4928683"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.nima.2004.07.226","article-title":"The temperature effect of Lu2SiO5: Ce3+ luminescence","volume":"537","author":"Chen","year":"2005","journal-title":"Nucl. Instrum. Methods. A"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1016\/j.optmat.2007.01.005","article-title":"Thermal effect on up-conversion in Er3+\/Yb3+ co-doped silicate glass","volume":"30","author":"Zhou","year":"2007","journal-title":"Opt. Mater."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.sna.2008.09.019","article-title":"Er3+\/Yb3+ codoped Gd2O3 nano-phosphor for optical thermometry","volume":"149","author":"Singh","year":"2009","journal-title":"Sens. Actuators A Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.optmat.2006.09.021","article-title":"Upconversion and temperature sensing behavior of Er3+ doped Bi2O3-Li2O-BaO-PbO tertiary glass","volume":"30","author":"Tripathi","year":"2007","journal-title":"Opt. Mater."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/12\/29839\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:53:48Z","timestamp":1760216028000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/12\/29839"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,12,10]]},"references-count":26,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2015,12]]}},"alternative-id":["s151229839"],"URL":"https:\/\/doi.org\/10.3390\/s151229839","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,12,10]]}}}