20.500.12556/RUL-142079 Ultrasonic photoacoustic emitter of graphene-nanocomposites film on a flexible substrate Photoacoustic devices generating high-amplitude and high-frequency ultrasounds are attractive candidates for medical therapies and on-chip bio-applications. Here, we report the photoacoustic response of graphene nanoflakes – Polydimethylsiloxane composite. A protocol was developed to obtain well-dispersed graphene into the polymer, without the need for surface functionalization, at different weight percentages successively spin-coated onto a Polydimethylsiloxane substrate. We found that the photoacoustic amplitude scales up with optical absorption reaching 11 MPa at ~ 228 mJ/cm$^2$ laser fluence. We observed a deviation of the pressure amplitude from the linearity increasing the laser fluence, which indicates a decrease of the Grüneisen parameter. Spatial confinement of high amplitude (> 40 MPa, laser fluence > 55 mJ/cm$^2$) and high frequency (Bw-6db ~ 21.5 MHz) ultrasound was achieved by embedding the freestanding film in an optical lens. The acoustic gain promotes the formation of cavitation microbubbles for moderate fluence in water and in tissue-mimicking material. Our results pave the way for novel photoacoustic medical devices and integrated components. ultrasonic photoacoustic composite photoacoustic materials laser ultrasonics photoacoustic lens acoustic cavitation graphene-polydimethylsiloxane composite kompoziti fotoakustični materiali laserski ultrazvoki fotoakustične leče akustična kavitacija true false true Angleški jezik Slovenski jezik Članek v reviji 2022-10-19 10:54:56 2022-10-19 10:54:57 2024-03-02 04:05:24 0000-00-00 00:00:00 2022 0 0 10 str. Vol. 28, art. 100413 Dec. 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 534 2213-5979 10.1016/j.pacs.2022.100413 126257667 1-s2.0-S2213597922000787-main.pdf 1-s2.0-S2213597922000787-main.pdf 1 32287DC19909D1FB42F1A927212BE3E4 5e42df45e36de11226313e3114aea2f9aa69261ad8ef7310ea5c37c38ed5f77a ae40fd17-d7a1-11ee-9a1b-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=181365 https://www.sciencedirect.com/science/article/pii/S2213597922000787 1 a6c5a514-4f8b-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=163343 Fakulteta za strojništvo 0 0 0