Transparent, flexible, ultrathin sound source devices using Indium Tin oxide films

Abstract

Thermoacoustic effects were observed in 100-nm indium tin oxide (ITO) films. The sound emission from the ITO films was measured as a function of power, distance, and frequency. Significant flat and wide frequency responses occurred between 20 and 50 kHz. The sound pressure and efficiency were in good agreement with theoretical results. This indicates that a thermoacoustic effect exists in metal-oxide materials and that a large family of transparent electrode materials may exhibit similar properties. Using the ultrathin, transparent, and flexible characteristics, we showed promising applications of ITO sound source devices that were integrated with liquid crystal display screens.

Gold Nanowire Thermophones

“…Such plateaus at high frequencies are characteristic of thermophones and were first observed by Shinoda et al [7]. This change in behavior usually attributed to near field interference [17] or heterogeneous substrates, whether in the form of multiple layers [7,11,8] or air domains [13], but neither of these are present in our thermophone.…”

“…Then in 2008, Xiao et al [16] demonstrated that freestanding films of carbon nanotubes (CNTs) could function as thermophones and be transparent, flexible, and stretchable. [16] This work directed attention towards other types of films composed of metals, [7] graphene, [8] indium tin oxide (ITO)-coated glass, [11] and the electronically conductive polymer PEDOT (poly (3,4-ethylenedioxythiophene)). [9] The objective of our work was to characterize the properties of ultra-long (mm scale) polycrystalline gold nanowires as thermophones.…”

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based organic, ultrathin, and transparent sound-emitting device

“…4 However, organic material in an acoustic application has not been reported. Recent work reported the application of metal, 5-9 carbon nanotube, [10][11][12][13] graphene, 14 and indium tin oxide 15 in the acoustic field. Inspired by such work, we propose the design of an organic sound-emitting device (SED) and investigate its acoustic properties.…”

Influence of thermodynamic properties of a thermo-acoustic emitter on the efficiency of thermal airborne ultrasound generation

“…Thus 20-30 nm thin and transparent airborne ultrasound emitters can be built and embedded in the screens of smart phones, tablets and other electronic devices [15].…”