title: Application of N-Doped Three-Dimensional Reduced Graphene Oxide Aerogel to Thin Film Loudspeaker.
abstract: We built a thermoacoustic loudspeaker employing N-doped three-dimensional reduced graphene oxide aerogel (N-rGOA) based on a simple template-free fabrication method. A two-step fabrication process, which includes freeze-drying and reduction/doping, was used to realize a three-dimensional, freestanding, and porous graphene-based loudspeaker, whose macroscopic structure can be easily modulated. The simplified fabrication process also allows the control of structural properties of the N-rGOAs, including density and area. Taking advantage of the facile fabrication process, we fabricated and analyzed thermoacoustic loudspeakers with different structural properties. The anlayses showed that a N-rGOA with lower density and larger area can produce a higher sound pressure level (SPL). Furthermore, the resistance of the proposed loudspeaker can be easily controlled through heteroatom doping, thereby helping to generate higher SPL per unit driving voltage. Our success in constructing an array of optimized N-rGOAs able to withstand input power as high as 40 W demonstrates that a practical thermoacoustic loudspeaker can be fabricated using the proposed mass-producible solution-based process.
authors.affiliation: School of Electrical Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Choong Sun
authors.initials: CS
authors.lastname: Kim
authors.affiliation: National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Kyung Eun
authors.initials: KE
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Sang Ouk
authors.initials: SO
authors.lastname: Kim
authors.affiliation: School of Electrical Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Byung Jin
authors.initials: BJ
authors.lastname: Cho
authors.affiliation: School of Electrical Engineering, KAIST , Daejeon 34141, Republic of Korea.
authors.forename: Jung-Woo
authors.initials: JW
authors.lastname: Choi
keywords: constructive interference; frequency response; graphene aerogel; sound pressure; thermoacoustic effect