Fully Printed Piezoelectric Polymer Loudspeakers with Enhanced Acoustic Performance

Abstract

Piezoelectric polymer loudspeakers have advantages like lightweight, flexibility, simple structure, and small volume, which make them favorable for a variety of applications. Herein, such loudspeakers are fabricated by screen printing the bottom and top electrodes (poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate), PEDOT:PSS) as well as the piezoelectric polymer layer (poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE)), in between on paper substrates. The dielectric properties of the printed loudspeakers are studied with dielectric spectroscopy. Thanks to the self-healing process during poling, the samples are successfully poled to saturation in spite of their large area of up to 300 cm 2 . The dependence of the acoustic output on remanent polarization and the active area of the piezoelectric layer is investigated. A sound pressure level (SPL) of about 91 dB at a distance of 1 m is obtained with array samples of five rectangular units (10 Â 6 cm 2 in area each). In particular, samples with two loudspeaker arrays printed, respectively, on both surfaces of the paper substrates are prepared, and a further increase of 6 dB in SPL is achieved when the two loudspeakers are driven in phase. The results not only deepen the understanding of fully printed piezoelectric polymer loudspeakers but also realize an SPL much higher than that reported in previous studies.

Printed Multilayer Piezoelectric Transducers on Paper for Haptic Feedback and Dual Touch-Sound Sensation

“…The SPL was recorded at a distance of 10 cm. It is worth mentioning that, despite the flat mounting of the device, which is in contrast to our former publications on printed piezoelectric loudspeakers [ 23 , 24 , 30 , 31 , 34 ] and the compact size of the transducer, a remarkably high SPL of more than 90 dB was achieved for a wide frequency range from ~2 kHz to 17 kHz. For the haptics application, the low frequency range between 100 and 500 Hz is important.…”

“…After finalizing all printing and annealing steps, all manufactured devices were polarized layer by layer to achieve high piezoelectricity of the P(VDF-TrFE) films. High remnant polarization of the piezoelectric layers is an important prerequisite to achieve high deflection of the actuator [ 24 ]. Figure 2 b shows the individual P-E-loops of printed multilayer devices with five active layers.…”

“…The small deviation of the curves clearly indicates the high layer-to-layer homogeneity with respect to the thickness and dielectric properties of the individual P(VDF-TrFE) layers and the conductivity of the electrodes, which is important to achieve highly efficient superposition of the forces generated by each individual active layer [ 24 ]. The decrease in capacitance for frequencies above ~2000 Hz can be attributed to the comparably low conductivity of the polymeric PEDOT:PSS electrodes as explained in detail in our former publications [ 30 , 31 ].…”

Potential Application of Organic Electronics in Electrical Sensing of Insects and Integrated Pest Management towards Developing Ecofriendly Replacements for Chemical Insecticides

“…Poling was done by applying a bipolar voltage sweep that allows separation of the dipole switching from the capacitive‐charging and conduction process. [ 50 ]…”

“…[51] Such printed piezoelectric transducers can be used for different applications like loudspeakers or haptic actuators. [50,52] Piezoelectricity Spectral Measurement: The setup is shown in Figure 12. The circuit consists of an amplifier including high-pass and low-pass filters that amplify the signal generated by the piezoelectric transducer when an insect walks on the surface.…”