No abstract

Embedding additional ferroelectric dipoles in contacting polymer layers is known to enhance the performance of triboelectricnanogenerator (TENG) devices. However, the influence of dipoles formed between the triboelectric surface charges on two contacting ferroelectric films has been ignored in all relevant studies. We demonstrate that proper attention to the alignment of the distinct dipoles present between two contacting surfaces and in composite polymer/BaTiO 3 ferroelectric films can lead to up to four times higher energy and power density output compared with cases when dipole arrangement is mismatched. For example, TENG device based on PVAc/BaTiO 3 shows energy density increase from 32.4 mJ m À2 to 132.9 mJ m À2 when comparing devices with matched and mismatched dipoles. The presented strategy and understanding of resulting stronger electrostatic induction in the contacting layers enable the development of TENG devices with greatly enhanced properties.

In this study, we investigate triboelectrification in polymer-based nanocomposites using identical polymer matrixes containing different concentrations of nanoparticles (NPs). The triboelectric surface charge density on polymer layers increased as the...

Thin films of p-and n-type organic semiconductors for thermo-electrical (TE) applications are produced by doping of tetrathiotetracene (TTT). To obtain p-type material TTT is doped with iodine during vacuum deposition of thin films or by post-deposition doping using controlled exposure to iodine vapors. Thermal co-deposition in vacuum of TTT and TCNQ is used to prepare n-type thin films. The attained thin films are characterized by measurements of Seebeck coefficient and electrical conductivity. Seebeck coefficient and conductivity could be varied by altering the doping level. P-type TTT:iodide thin films with a power factor of 0.52 μWm -1 K -2 , electrical conductivity of 130 S m -1 and Seebeck coefficient of 63 μV K -1 and n-type TCNQ:TTT films with power factor of 0.33 μWm -1 K -2 , electrical conductivity of 57 S m -1 and Seebeck coefficient of -75 μV K -1 are produced. Engineered deposition of both p-and n-type thermoelectric conducting elements on the same substrate is demonstrated. A proof of concept prototype of planar thin film TE generator based on a single p-n couple from the organic materials is built and its power generation characterized.

In this paper we describe the principles of operation as well as the fabrication and testing steps of an all-organic waveguide modulator. The modulator comprises an SU-8 core and an electro-optic host-guest polymer cladding. The polymer properties are tuned in order to achieve single mode operation. We used direct-write laser lithography in two steps for the preparation of the devices. The electro-optic coefficient of the polymer is estimated from observing the modulation of the device operated in push-pull mode.