Highly sensitive thermoelectric touch sensor based on p-type SnO _x thin film

Abstract

Here, the ability of using p-type tin oxide (SnOx) thin films as a thermal sensor has been investigated. Firstly, the thermoelectric performance was optimized by controlling the thickness of the SnOx film from 60 up to 160 nm. A high Seebeck coefficient of +263 μV K−1 and electrical conductivity of 4.1 × 102 (S m−1) were achieved in a 60 nm thick SnOx film, due to a compact nanostructured film and the absence of the Sn metallic phase, which was observed for the thicker SnOx film leading to a typical thermoelectric transport properties of a n-type Sn film. Moreover, x-ray photoelectron spectroscopy revealed the co-existence of SnO (79.7%) and SnO2 (20.3%) phases in the 60 nm thick SnOx film, while the optical measurements revealed an indirect gap of 1.8 eV and a direct gap of 2.7 eV, respectively. The 60 nm-SnOx thin film have been tested as a thermoelectric touch sensor, achieving a Vsignal/Vnoise ≈ 20, with a rise time <1 s. Therefore, this work provides an efficient way for developing highly efficient thermal sensors with potential use in display technologies.

Boosting the Thermoelectric Properties of PEDOT:PSS via Low‐Impact Deposition of Tin Oxide Nanoparticles

“…Oxygen vacancies at the NP surface would render the SnO x -NPs a p-type semiconductor. [17] To quantify the composition of the SnO x -NPs, XPS spectra of the Sn3d core level region were collected. The Sn3d 5/2 component is shown in Figure 3d.…”

“…This is consistent with reports for SnO x films of thickness below 60 nm, where the same high oxidation state was observed. [17] The peak at higher binding energy (BE) (red dashed line in Figure 3d), is attributed to Sn 4+ coordinated by oxygen from PSS − . [22,23] This is clear evidence for the interaction between SnO x -NPs and PSS.…”

“…Tin (Sn) electrodes were selected to prepare Sn-based NPs because they are non-toxic, active in electrical performance and Sn and its oxides were recently reported to have interesting TE properties. [17]…”

Integrated, Highly Flexible, and Tailorable Thermoelectric Type Temperature Detectors Based on a Continuous Carbon Nanotube Fiber

“…A lot of efforts have been devoted toward the development of new TE temperature detectors over the past few decades. [9][10][11][12][13][14][15] Obviously, the TE material is the key for a TE temperature detector, while traditional inorganic TE materials are usually hard. [16,17] Flexible and lightweight TE materials are desirable and beneficial to the future application of detectors.…”

Flexible wearable sensors - an update in view of touch-sensing

“…The evaporation often involves two basic processes: a hot source material evaporates and condenses on the substrate. For example, Vieira et al[77] proposed a highly sensitive thermoelectric touch sensor based on p-type SnO x thin film. Thermal oxidation films (the thickness of 60 -160 nm, the deposition rate of 2 Å s -1 , and the pressure of 2 × 10 -5 mbar) deposited in borosilicate glass substrate was performed in the air-atmosphere at 250 °C for 3 h. As a result, the touch sensor (from 60 nm-SnO x thin films) achieves a high sensitivity ( / ≈ 20), with a rise time < 1 s. Schematic illustrations: (a) The flexible electrode using spin coating with electroninduced perpendicular graphene (EIPG), anodic aluminum oxide (AAO), and polydimethylsiloxane (PDMS).…”