▎ 摘　　要

Graphene thermoacoustic loudspeakers, composed of a graphene film on a substrate, generate sound with heat. Improving thermoacoustic efficiency of graphene speakers is a goal for optimal design. In this work, we first modified the existing TA model with respect to small thermal wavelengths, and then built an acoustic platform for model validation. Additionally, sensitivity analyses for influential factors on thermoacoustic efficiency were performed, including the thickness of multilayered graphene films, the thermal effusivity of substrates, and the characteristics of inserted gases. The higher sensitivity coefficients result in the stronger effects on thermoacoustic efficiency. We find that the thickness (5 nm-15 nm) of graphene films plays a trivial role in efficiency, resulting in the sensitivity coefficient less than 0.02. The substrate thermal effusivity, however, has significant effects on efficiency, with the sensitivity coefficient around 1.7. Moreover, substrates with a lower thermal effusivity show better acoustic performances. For influences of ambient gases, the sensitivity coefficients of density rho(g), thermal conductivity kappa(g), and specific heat c(p,g) are 2.7, 0.98, and 0.8, respectively. Furthermore, large magnitudes of both rho(g) and kappa(g) lead to a higher efficiency and the sound pressure level generated by graphene films is approximately proportional to the inverse of c(p,g). These findings can refer to the optimal design for graphene thermoacoustic speakers. Published by AIP Publishing.