Layer-by-layer fabrication of highly transparent polymer based piezoelectric transducers

Abstract

The fabrication of highly transparent piezoelectric transducers is of increasing interest in the scientific and technological community. In this work, polymer based piezoelectric transducers were fabricated by the direct deposition of each layer forming the transducer on the desired substrate, avoiding the use of coupling layers. Transparent conductive oxide (TCO) electrodes were deposited by magnetron sputtering and piezoelectric films based on the copolymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) were deposited by spin-coating. All layers were processed and characterized to obtain a highly transparent piezoelectric P(VDF-TrFE) transducer with a strong adhesion between layers and preserving the piezoelectric response of the copolymer film. Indium tin oxide (ITO), gallium-doped zinc oxide (GZO) and aluminium-doped zinc oxide (AZO) were evaluated, and the best performance was obtained with AZO. The optimized transducer features an optical transmittance higher than 75 % in the visible spectral range and a piezoelectric coefficient |d33| of 34 pC.N-1 .

Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir–Blodgett Method

“…Due to the simple process and good quality of prepared films, there has been a considerable amount of research on prompting the formation of β phase in spin-coated PVDF films [18,22,25,[35][36][37][38][39][40][41][42][43][44][45]. The general process can roughly be divided into three steps: solution preparation, spin-coating, and annealing.…”

Smart and Multifunctional Materials Based on Electroactive Poly(vinylidene fluoride): Recent Advances and Opportunities in Sensors, Actuators, Energy, Environmental, and Biomedical Applications

“…11 For smaller thicknesses, from hundreds tens of nanometers to dozens of micrometers, spin-coating is applied to produce highly uniform films deposited directly on the desired substrates. 71,72 Films and specific structures can be also achieved by using additive manufacturing technologies, such as inkjet-printing, screen-printing, and spray-printing. 73 In this case, dense or porous morphologies can be obtained by specific postprocessing thermal treatments.…”

“…A transition from α- to β-phase can be induced by mechanical stretching of the α-film at a specific temperature and electrical poling is applied to optimize the electroactive response by favoring the orientation of the dipoles along the direction of the applied field . For smaller thicknesses, from hundreds tens of nanometers to dozens of micrometers, spin-coating is applied to produce highly uniform films deposited directly on the desired substrates. , Films and specific structures can be also achieved by using additive manufacturing technologies, such as inkjet-printing, screen-printing, and spray-printing . In this case, dense or porous morphologies can be obtained by specific postprocessing thermal treatments.…”

“…An optimized system was developed for the same purpose . In this case, the piezoelectric transducer is based on a 25 μm thick poly­(VDF- co -TrFE) film with aluminum doped zinc oxide (AZO) electrodes fabricated by a layer-by-layer deposition approach so that the entire system is transparent in the visible light spectrum , and allows optical detection (Figure d). The piezoelectric transducer, featuring a piezoelectric | d 33 | coefficient of 34 pC·N –1 , was integrated underneath a PDMS microfluidic system and actuated with a peak-to-peak voltage amplitude of 10 V and a frequency of 48 MHz.…”