Thermoacoustic
(TA) effect has been discovered for more than 130
years. However, limited by the material characteristics, the performance
of a TA sound source could not be compared with magnetoelectric and
piezoelectric loudspeakers. Recently, graphene, a two-dimensional
material with the lowest heat capacity per unit area, was discovered
to have a good TA performance. Compared with a traditional sound source,
graphene TA sound sources (GTASSs) have many advantages, such as small
volume, no diaphragm vibration, wide frequency range, high transparency,
good flexibility, and high sound pressure level (SPL). Therefore,
graphene has a great potential as a next-generation sound source.
Photoacoustic (PA) imaging can also be applied to the diagnosis and
treatment of diseases using the photothermo-acoustic (PTA) effect.
Therefore, in this review, we will introduce the history of TA devices.
Then, the theory and simulation model of TA will be analyzed in detail.
After that, we will talk about the graphene synthesis method. To improve
the performance of GTASSs, many strategies such as lowering the thickness
and using porous or suspended structures will be introduced. With
a good PTA effect and large specific area, graphene PA imaging and
drug delivery is a promising prospect in cancer treatment. Finally,
the challenges and prospects of GTASSs will be discussed.