Flexible thermistors: pulsed laser-induced liquid-phase sintering of spinel Mn–Co–Ni oxide films on polyethylene terephthalate sheets

Abstract

Flexible Co and Ni doped Mn3O4 spinel oxide thermistors with a high B constant and quick response.

Low-temperature crystallization of solution-derived metal oxide thin films assisted by chemical processes

“…Flexible sensors are required for a wide range of biomedical applications where the rigid counterparts present some technical limitations. For example, thermal sensors integrated on flexible polymer substrates may provide significant benefits for 50 The resulting devices show strong variations on their electrical resistance with small changes in temperature, particularly a negative-temperature-coefficient (NTC) behavior, which confirms their suitability for flexible sensors in skin thermography applications. Particularly, when evaluating the temperature sensing properties in a finger approach test, the response of the metal oxide thin film thermistor results much faster and more precise compared to that given by a commercial rigid ceramic chip thermistor.…”

Laser Irradiation of Metal Oxide Films and Nanostructures: Applications and Advances

“…Hence, the transfer of laser‐induced heat in amorphous and partially crystalline materials will be constrained to smaller distances. Pores in the microstructure of metal oxide films will affect the absorption of UV laser radiation . For dense precursor films, the incident UV laser and thermal transport cannot reach the bottom of the film (≈2 µm thick) sufficiently because of the shallow penetration of UV wavelengths.…”

“…However, the development of Mn‐spinel‐oxide‐based flexible thermistors is limited by the high fabrication temperatures. To overcome this limitation, Nakajima and Tsuchiya employed the laser‐induced photoreaction of NPs of a Mn‐spinel oxide coated on a flexible PET substrate . An NP (200–400 nm) ink of Mn 1.56 Co 0.96 Ni 0.48 O 4 (MCN) was prepared by wet milling of polycrystalline MCN powders with metal organic salts of Mn, Co, and Ni dissolved in toluene (MCN solution).…”

“…j) Calculated temperature increase time for commercial and laser irradiated MCN thermistors. Reproduced with permission . Copyright 2015, The Royal Society of Chemistry.…”

“…Laser systems operating in continuous‐wave (CW) or pulsed modes at wavelengths in the ultraviolet (UV), visible (vis), and infrared (IR) ranges have been employed to tailor the properties/functionality of metal oxides. Laser irradiation of a wide variety of MO films and nanostructures has been conducted for their applications in dielectric, ferroelectric, piezoelectric, and multiferroic magnetoelectric devices, photocatalysis, gas sensors, transparent conductors, field‐effect transistors, solar cells, and thermistors ( Figure ). Besides the overarching goal of tailoring of the physical and chemical properties, several interesting phenomena induced by laser irradiation have been reported, e.g., structural distortion and transformation, diamagnetic to ferromagnetic switching, modification of exchange bias, wettability switching, p‐type to n‐type conductivity transformation, resistive switching, metal‐to‐insulator transition (MIT), and electrochromic switching …”