{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T19:07:43Z","timestamp":1771960063111,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2015,4,22]],"date-time":"2015-04-22T00:00:00Z","timestamp":1429660800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002322","name":"CAPES","doi-asserted-by":"publisher","award":["CAPES-MES-Cuba 134\/11"],"award-info":[{"award-number":["CAPES-MES-Cuba 134\/11"]}],"id":[{"id":"10.13039\/501100002322","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003593","name":"CNPq","doi-asserted-by":"publisher","award":["MCT\/CNPq\/CT-INFO 17\/2009; 142302\/2010-4"],"award-info":[{"award-number":["MCT\/CNPq\/CT-INFO 17\/2009; 142302\/2010-4"]}],"id":[{"id":"10.13039\/501100003593","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001807","name":"FAPESP","doi-asserted-by":"publisher","award":["08\/57706-4; 09\/05589-7; 11\/17184-1; 13\/19420-0"],"award-info":[{"award-number":["08\/57706-4; 09\/05589-7; 11\/17184-1; 13\/19420-0"]}],"id":[{"id":"10.13039\/501100001807","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Electronic devices based on organic thin-film transistors (OTFT) have the potential to supply the demand for portable and low-cost gadgets, mainly as sensors for in situ disease diagnosis and environment monitoring. For that reason, poly(3-hexylthiophene) (P3HT) as the active layer in the widely-used bottom-gate\/bottom-contact OTFT structure was deposited over highly-doped silicon substrates covered with thermally-grown oxide to detect vapor-phase compounds. A ten-fold organochloride and ammonia sensitivity compared to bare sensors corroborated the application of this semiconducting polymer in sensors. Furthermore, P3HT TFTs presented approximately three-order higher normalized sensitivity than any chemical sensor addressed herein. The results demonstrate that while TFTs respond linearly at the lowest concentration values herein, chemical sensors present such an operating regime mostly above 2000 ppm. Simultaneous alteration of charge carrier mobility and threshold voltage is responsible for pushing the detection limit down to units of ppm of ammonia, as well as tens of ppm of alcohol or ketones. Nevertheless, P3HT transistors and chemical sensors could compose an electronic nose operated at room temperature for a wide range concentration evaluation (1\u201310,000 ppm) of gaseous analytes. Targeted analytes include not only biomarkers for diseases, such as uremia, cirrhosis, lung cancer and diabetes, but also gases for environment monitoring in food, cosmetic and microelectronics industries.<\/jats:p>","DOI":"10.3390\/s150409592","type":"journal-article","created":{"date-parts":[[2015,4,22]],"date-time":"2015-04-22T12:14:23Z","timestamp":1429704863000},"page":"9592-9609","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":55,"title":["Enhanced Sensitivity of Gas Sensor Based on  Poly(3-hexylthiophene) Thin-Film Transistors for  Disease Diagnosis and Environment Monitoring"],"prefix":"10.3390","volume":"15","author":[{"given":"Marco","family":"Cavallari","sequence":"first","affiliation":[{"name":"Departamento de Engenharia de Sistemas Eletr\u00f4nicos, Escola Polit\u00e9cnica da Universidade de S\u00e3o Paulo (EPUSP), Av. Prof. Luciano Gualberto, trav. 3, n. 158, Cidade Universit\u00e1ria, CEP 05508-900,  S\u00e3o Paulo-SP, Brasil"}]},{"given":"Jos\u00e9","family":"Izquierdo","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia de Sistemas Eletr\u00f4nicos, Escola Polit\u00e9cnica da Universidade de S\u00e3o Paulo (EPUSP), Av. Prof. Luciano Gualberto, trav. 3, n. 158, Cidade Universit\u00e1ria, CEP 05508-900,  S\u00e3o Paulo-SP, Brasil"},{"name":"Instituto Superior Polit\u00e9cnico Jos\u00e9 Antonio Echeverr\u00eda (ISPJAE), Centro de Investigaciones de Microelectr\u00f3nica (CIME), Antigua Carretera de Vento, km 8 1\/2, Boyeros, CP 10800 La Habana, Cuba"}]},{"given":"Guilherme","family":"Braga","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia de Sistemas Eletr\u00f4nicos, Escola Polit\u00e9cnica da Universidade de S\u00e3o Paulo (EPUSP), Av. Prof. Luciano Gualberto, trav. 3, n. 158, Cidade Universit\u00e1ria, CEP 05508-900,  S\u00e3o Paulo-SP, Brasil"},{"name":"EMBRAPA Instrumenta\u00e7\u00e3o, Rua Quinze de Novembro, 1452-Centro,  CEP 13560-970 S\u00e3o Carlos, SP, Brasil."}]},{"given":"Ely","family":"Dirani","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia de Sistemas Eletr\u00f4nicos, Escola Polit\u00e9cnica da Universidade de S\u00e3o Paulo (EPUSP), Av. Prof. Luciano Gualberto, trav. 3, n. 158, Cidade Universit\u00e1ria, CEP 05508-900,  S\u00e3o Paulo-SP, Brasil"},{"name":"Pontif\u00edcia Universidade Cat\u00f3lica de S\u00e3o Paulo (PUC-SP), Rua Marqu\u00eas de Paranagu\u00e1,  111-Consola\u00e7\u00e3o, CEP 01303-050 S\u00e3o Paulo-SP, Brasil"}]},{"given":"Marcelo","family":"Pereira-da-Silva","sequence":"additional","affiliation":[{"name":"Instituto de F\u00edsica de S\u00e3o Carlos\u2013USP, Av. Trabalhador S\u00e3ocarlense 400,  CEP 13566-590 S\u00e3o Carlos-SP, Brasil"},{"name":"Centro Universit\u00e1rio Central Paulista\u2013UNICEP, Rua Miguel Petroni 5111,  CEP 13563-470 S\u00e3o Carlos-SP, Brasil"}]},{"given":"Estrella","family":"Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Instituto Superior Polit\u00e9cnico Jos\u00e9 Antonio Echeverr\u00eda (ISPJAE), Centro de Investigaciones de Microelectr\u00f3nica (CIME), Antigua Carretera de Vento, km 8 1\/2, Boyeros, CP 10800 La Habana, Cuba"}]},{"given":"Fernando","family":"Fonseca","sequence":"additional","affiliation":[{"name":"Departamento de Engenharia de Sistemas Eletr\u00f4nicos, Escola Polit\u00e9cnica da Universidade de S\u00e3o Paulo (EPUSP), Av. Prof. Luciano Gualberto, trav. 3, n. 158, Cidade Universit\u00e1ria, CEP 05508-900,  S\u00e3o Paulo-SP, Brasil"}]}],"member":"1968","published-online":{"date-parts":[[2015,4,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"273A","DOI":"10.1021\/ac041600+","article-title":"Don\u2019t waste your breath","volume":"76","author":"Mukhopadhyay","year":"2004","journal-title":"Anal. Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.trac.2011.09.013","article-title":"A review of breath analysis for diagnosis of human health","volume":"33","author":"Kim","year":"2012","journal-title":"TrAC Trends Anal. 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