Ultrasonic photoacoustic emitter of graphene-nanocomposites film on a flexible substrate

Vella, Daniele (author), Mrzel, Aleš (author), Drnovšek, Aljaž (author), Shvalya, Vasyl (author), Jezeršek, Matija (author)

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.

• Language: English
• Keywords: ultrasonic photoacoustic composite, photoacoustic materials, laser ultrasonics, photoacoustic lens, acoustic cavitation, graphene-polydimethylsiloxane composite
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 10 str.
• Numbering: Vol. 28, art. 100413
• PID: 20.500.12556/RUL-142079
• UDC: 534
• ISSN on article: 2213-5979
• DOI: 10.1016/j.pacs.2022.100413
• COBISS.SI-ID: 126257667
• Publication date in RUL: 19.10.2022

Record is a part of a journal

• Title: Photoacoustics
• Publisher: Elsevier
• ISSN: 2213-5979
• COBISS.SI-ID: 519718169

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: kompoziti, fotoakustični materiali, laserski ultrazvoki, fotoakustične leče, akustična kavitacija