PVDF-TrFE/BSTO composite polymer based transducers for high resolution ultrasound and photoacoustic imaging

This work demonstrates the fabrication of high-frequency ultrasound transducers, which are capable of sensing high-frequency and broad bandwidth photoacoustics and ultrasound signals. For sensor film fabrication purposes, a piezoelectric composite polymer consisting of PVDF-TrFE (Polyvinylidene difluoride trifluoroethylene) and lab-synthesized single crystal BSTO (Barium Strontium Titanate) nanofiller is used. The piezoelectric efficiency after the addition of BSTO in PVDF-TrFE is characterized using FTIR spectroscopy. The fabricated transducers are tested in the pulse-echo mode and the central frequency is found up to 43 MHz with a bandwidth of 40 MHz (93% at -6dB). Photoacoustic signals of frequency 14.5MHz and bandwidth of more than 100% are detected using the fabricated transducers. The transducers are used for photoacoustic imaging of two photoacoustic sources. The high sensitivity and broad frequency spectrum of the transducers make them suitable for high-resolution photoacoustics and ultrasound imaging for biomedical imaging and nondestructive testing.