{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T17:33:56Z","timestamp":1778175236824,"version":"3.51.4"},"reference-count":33,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,2,2]],"date-time":"2021-02-02T00:00:00Z","timestamp":1612224000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MTEC Global Co. Ltd","award":["N\/A"],"award-info":[{"award-number":["N\/A"]}]},{"DOI":"10.13039\/100000070","name":"National Institute of Biomedical Imaging and Bioengineering","doi-asserted-by":"publisher","award":["R00EB017729-04"],"award-info":[{"award-number":["R00EB017729-04"]}],"id":[{"id":"10.13039\/100000070","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We report flexible thin-film lead zirconate titanate (PZT)-based ultrasonic transducers on polyimide substrates. The transducers are bar resonators designed to operate in the width extension mode. The active elements are 1 \u00b5m thick PZT films that were crystallized on Si substrates at 700 \u00b0C and transferred to 5 \u00b5m thick solution-cast polyimide via dissolution of an underlying release layer. Underwater pitch\u2013catch testing between two neighboring 100 \u00b5m \u00d7 1000 \u00b5m elements showed a 0.2 mV signal at a 1.5 cm distance for a driving voltage of 5 V peak at 9.5 MHz. With the same excitation, a 33 kPa sound pressure output at a 6 mm distance and a 32% bandwidth at \u22126 dB were measured by hydrophone.<\/jats:p>","DOI":"10.3390\/s21031014","type":"journal-article","created":{"date-parts":[[2021,2,2]],"date-time":"2021-02-02T13:01:12Z","timestamp":1612270872000},"page":"1014","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Flexible Thin-Film PZT Ultrasonic Transducers on Polyimide Substrates"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1910-1656","authenticated-orcid":false,"given":"Tianning","family":"Liu","sequence":"first","affiliation":[{"name":"School of Electrical Engineering and Computer Science, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ajay","family":"Dangi","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jeong Nyeon","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Engineering Science and Mechanics, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4010-1047","authenticated-orcid":false,"given":"Sri-Rajasekhar","family":"Kothapalli","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kyusun","family":"Choi","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Computer Science, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Susan","family":"Trolier-McKinstry","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Computer Science, Penn State University, University Park, PA 16802, USA"},{"name":"Department of Materials Science and Engineering, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas","family":"Jackson","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Computer Science, Penn State University, University Park, PA 16802, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1111\/j.1540-8175.1990.tb00378.x","article-title":"Intravascular and Intracardiac ultrasound imaging: Current research and future directions","volume":"7","author":"Pandian","year":"1990","journal-title":"Echocardiography"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1109\/TUFFC.2006.1593387","article-title":"Annular-ring CMUT arrays for forward-looking IVUS: Transducer characterization and imaging","volume":"53","author":"Degertekin","year":"2006","journal-title":"IEEE Trans. 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