{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T11:47:41Z","timestamp":1777895261610,"version":"3.51.4"},"reference-count":37,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,30]],"date-time":"2022-12-30T00:00:00Z","timestamp":1672358400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Grassroots ICT Research Initiative Fund","award":["NGIRI-2020-3423"],"award-info":[{"award-number":["NGIRI-2020-3423"]}]},{"name":"ORIC Internal Research Grant Sukkur IBA University","award":["NGIRI-2020-3423"],"award-info":[{"award-number":["NGIRI-2020-3423"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we report a fast, linear wide-range hybrid flexible sensor based on a novel composite of strontium titanate (SrTiO3) and poly 3,4 ethylenedioxythiophene polystyrene sulfonate (PEDOT: PSS) as a sensing layer. Inter-digitate electrodes (IDEs) were printed for humidity monitoring (finger: 250 \u00b5m; spacing: 140 \u00b5m; length: 8 mm) whilst a meander-based pattern was printed for the temperature measurement (meander thickness: 180 \u00b5m; spacing: 400 \u00b5m) on each side of the PET substrate using silver ink. Moreover, active layers with different concentration ratios were coated on the electrodes using a spray coating technique. The as-developed sensor showed an excellent performance, with a humidity measurement range of (10\u201390% RH) and temperature measurement range of (25\u201390 \u00b0C) with a fast response (humidity: 5 s; temperature: 4.2 s) and recovery time (humidity: 8 s; temperature: 4.4 s). The reliability of the sensor during mechanical bending of up to 5.5 mm was validated with a reliable performance. The sensor was also used in real-world applications to measure human respiration. For this, a suggested sensor-based autonomous wireless node was included in a 3D-printed mask. The manufactured sensor was an excellent contender for wearable and environmental applications because of its exceptional performance, which allowed for the simultaneous measurement of both quantities by a single sensing device.<\/jats:p>","DOI":"10.3390\/s23010401","type":"journal-article","created":{"date-parts":[[2023,1,2]],"date-time":"2023-01-02T03:08:59Z","timestamp":1672628939000},"page":"401","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Wide-Range Humidity\u2013Temperature Hybrid Flexible Sensor Based on Strontium Titanate and Poly 3,4 Ethylenedioxythiophene Polystyrene Sulfonate for Wearable 3D-Printed Mask Applications"],"prefix":"10.3390","volume":"23","author":[{"given":"Adnan","family":"Ahmed","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0352-9319","authenticated-orcid":false,"given":"Afaque Manzoor","family":"Soomro","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"},{"name":"Department of Mechatronics Engineering, Jeju National University, Jeju-si 690756, Republic of Korea"}]},{"given":"Darshan","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"}]},{"given":"Muhammad","family":"Waqas","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"}]},{"given":"Kashif Hussain","family":"Memon","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"}]},{"given":"Faheem","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Department of Mechatronics Engineering, Jeju National University, Jeju-si 690756, Republic of Korea"}]},{"given":"Suresh","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Sukkur IBA University, Sukkur 65200, Pakistan"}]},{"given":"Hina","family":"Ashraf","sequence":"additional","affiliation":[{"name":"Department of Ocean Sciences, Jeju National University, Jeju-si 690756, Republic of Korea"}]},{"given":"Kyung Hyun","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Mechatronics Engineering, Jeju National University, Jeju-si 690756, Republic of Korea"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1016\/j.future.2016.05.032","article-title":"A robust and anonymous patient monitoring system using wireless medical sensor networks","volume":"80","author":"Amin","year":"2018","journal-title":"Futur. Gener. Comput. Syst."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Jawad, H.M., Nordin, R., Gharghan, S.K., Jawad, A.M., and Ismail, M. (2017). Energy-efficient wireless sensor networks for precision agriculture: A review. Sensors, 17.","DOI":"10.3390\/s17081781"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"751","DOI":"10.1016\/j.foodchem.2016.11.107","article-title":"Doped graphene\/Cu nanocomposite: A high sensitivity non-enzymatic glucose sensor for food","volume":"221","author":"Shabnam","year":"2017","journal-title":"Food Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"354","DOI":"10.1016\/j.snb.2018.03.134","article-title":"Wide range highly sensitive relative humidity sensor based on series combination of MoS2 and PEDOT:PSS sensors array","volume":"266","author":"Siddiqui","year":"2018","journal-title":"Sens. Actuators B Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"252106","DOI":"10.1063\/1.4989681","article-title":"Permanent water swelling effect in low temperature thermally reduced graphene oxide","volume":"110","author":"Papamatthaiou","year":"2017","journal-title":"Appl. Phys. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1166\/sl.2005.045","article-title":"Humidity sensors: A review of materials and mechanisms","volume":"3","author":"Chen","year":"2005","journal-title":"Sens. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1016\/j.apsusc.2017.01.064","article-title":"Reduced graphene oxide decorated with Fe doped SnO 2 nanoparticles for humidity sensor","volume":"402","author":"Toloman","year":"2017","journal-title":"Appl. Surf. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1487","DOI":"10.1039\/c2an15800k","article-title":"Water-resistive humidity sensor prepared by printing process using polyelectrolyte ink derived from new monomer","volume":"137","author":"Kim","year":"2012","journal-title":"Analyst"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"702","DOI":"10.1109\/16.830983","article-title":"A high-speed capacitive humidity sensor with on-chip thermal reset","volume":"47","author":"Kang","year":"2000","journal-title":"IEEE Trans. Electron Devices"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/srep02714","article-title":"Ultrahigh humidity sensitivity of graphene oxide","volume":"3","author":"Bi","year":"2013","journal-title":"Sci. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"24329","DOI":"10.3390\/s141224329","article-title":"All-Optical Graphene Oxide Humidity Sensors","volume":"14","author":"Lim","year":"2014","journal-title":"Sensors"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"19882","DOI":"10.1021\/acsami.5b06883","article-title":"Highly sensitive and fast response colorimetric humidity sensors based on graphene oxides film","volume":"7","author":"Chi","year":"2015","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1149\/04901.0445ecst","article-title":"Surface Acoustic Wave Humidity Sensors Based on Graphene Oxide Thin Films Deposited with the Surface Acoustic Wave Atomizer","volume":"49","author":"Balashov","year":"2012","journal-title":"ECS Trans."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.snb.2011.12.037","article-title":"A novel surface acoustic wave-impedance humidity sensor based on the composite of polyaniline and poly(vinyl alcohol) with a capability of detecting low humidity","volume":"165","author":"Li","year":"2012","journal-title":"Sens. Actuators B Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"4444","DOI":"10.1039\/c3ta01401k","article-title":"Porous-layered stack of functionalized AuNP-rGO (gold nanoparticles-reduced graphene oxide) nanosheets as a sensing material for the micro-gravimetric detection of chemical vapor","volume":"1","author":"Yu","year":"2013","journal-title":"J. Mater. Chem. A"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"9455","DOI":"10.1007\/s10854-019-01277-1","article-title":"All-range flexible and biocompatible humidity sensor based on poly lactic glycolic acid (PLGA) and its application in human breathing for wearable health monitoring","volume":"30","author":"Soomro","year":"2019","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"921","DOI":"10.1016\/j.snb.2018.07.004","article-title":"Barium titanate nanoparticle based nonlinear optical humidity sensor","volume":"273","author":"Reynolds","year":"2018","journal-title":"Sens. Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1186\/s11671-019-3084-x","article-title":"Mini Review on Flexible and Wearable Electronics for Monitoring Human Health Information","volume":"14","author":"Gu","year":"2019","journal-title":"Nanoscale Res. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4338","DOI":"10.1002\/adma.201504244","article-title":"Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human-Activity Monitoringand Personal Healthcare","volume":"28","author":"Trung","year":"2016","journal-title":"Adv. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"4","DOI":"10.4258\/hir.2017.23.1.4","article-title":"Wearable devices in medical internet of things: Scientific research and commercially available devices","volume":"23","author":"Haghi","year":"2017","journal-title":"Healthc. Inform. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2204781","DOI":"10.1002\/adfm.202204781","article-title":"Bipolar Junction Transistor Exhibiting Excellent Output Characteristics with a Prompt Response against the Selective Protein","volume":"32","author":"Dastgeer","year":"2022","journal-title":"Adv. Funct. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"22879","DOI":"10.1039\/C5RA00451A","article-title":"Humidity sensing properties of SrTiO3 nanospheres with high sensitivity and rapid response","volume":"5","author":"Li","year":"2015","journal-title":"RSC Adv."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1002\/inf2.12060","article-title":"Physical sensors for skin-inspired electronics","volume":"2","author":"Li","year":"2020","journal-title":"InfoMat"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"828","DOI":"10.1021\/acssensors.7b00199","article-title":"Fast-Response and Flexible Nanocrystal-Based Humidity Sensor for Monitoring Human Respiration and Water Evaporation on Skin","volume":"2","author":"Kano","year":"2017","journal-title":"ACS Sens."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"5509","DOI":"10.1038\/s41598-020-62397-x","article-title":"Printable Highly Stable and Superfast Humidity Sensor Based on Two Dimensional Molybdenum Diselenide","volume":"10","author":"Awais","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"18650","DOI":"10.1021\/acsami.8b02915","article-title":"Biocompatible Collagen Nanofibrils: An Approach for Sustainable Energy Harvesting and Battery-Free Humidity Sensor Applications","volume":"10","author":"Vivekananthan","year":"2018","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2472","DOI":"10.1039\/D0QM00159G","article-title":"3D printed composites from heat extruded polycaprolactone\/sodium alginate filaments and their heavy metal adsorption properties","volume":"4","author":"Liakos","year":"2020","journal-title":"Mater. Chem. Front."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Sappat, A., Wisitsoraat, A., Sriprachuabwong, C., Jaruwongrungsee, K., Lomas, T., and Tuantranont, A. (2011, January 17\u201319). Humidity sensor based on piezoresistive microcantilever with inkjet printed PEDOT\/PSS sensing layers. Proceedings of the The 8th Electrical Engineering\/Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand\u2014Conference 2011 (IEEE), Khon Kaen, Thailand.","DOI":"10.1109\/ECTICON.2011.5947764"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.proeng.2011.12.004","article-title":"Why Going Towards Plastic and Flexible Sensors?","volume":"25","author":"Briand","year":"2011","journal-title":"Procedia Eng."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1016\/j.snb.2011.12.007","article-title":"Humidity sensing behaviors of graphene oxide-silicon bi-layer flexible structure","volume":"161","author":"Yao","year":"2012","journal-title":"Sens. Actuators B Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/j.snb.2015.08.052","article-title":"Detection of very low humidity using polyelectrolyte\/graphene bilayer humidity sensors","volume":"222","author":"Li","year":"2016","journal-title":"Sens. Actuators B Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/S0925-4005(02)00233-2","article-title":"Bilayer thin film humidity sensors based on sodium polystyrenesulfonate and substituted polyacetylenes","volume":"87","author":"Li","year":"2002","journal-title":"Sens. Actuators B Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1016\/j.sna.2018.08.017","article-title":"Nickel substituted cadmium ferrite as room temperature operable humidity sensor","volume":"280","author":"Chethan","year":"2018","journal-title":"Sens. Actuators A Phys."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"76","DOI":"10.1016\/S0925-4005(99)00487-6","article-title":"Comparative study on micromorphology and humidity sensitive properties of thin-film and thick-film humidity sensors based on semiconducting MnWO4","volume":"64","author":"Qu","year":"2000","journal-title":"Sens. Actuators B Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"015005","DOI":"10.1088\/1674-4926\/32\/1\/015005","article-title":"Surface-type humidity sensor based on cellulose-PEPC for telemetry systems","volume":"32","author":"Karimov","year":"2011","journal-title":"J. Semicond."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1080\/10584587.2013.787828","article-title":"Electrical and Humidity Sensing Properties of Graphene and Polystyrene Sulfonic Sodium Bilayer Thin Film","volume":"144","author":"Huang","year":"2013","journal-title":"Integr. Ferroelectr."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/j.sna.2017.08.040","article-title":"Thermally modified amorphous polyethylene oxide thin films as highly sensitive linear humidity sensors","volume":"265","author":"Sajid","year":"2017","journal-title":"Sens. Actuators A Phys."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/1\/401\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:56:22Z","timestamp":1760147782000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/1\/401"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,30]]},"references-count":37,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["s23010401"],"URL":"https:\/\/doi.org\/10.3390\/s23010401","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,30]]}}}