Flexible electronics is an emerging and cutting‐edge technology which is considered as the building blocks of the next generation micro‐nano electronics. Flexible electronics integrate both active and passive functions in devices, driving rapid developments in healthcare, the Internet of Things (IoT), and industrial fields. Among them, flexible temperature sensors, which can be directly attached to human skin or curved surfaces of objects for continuous and stable temperature measurement, have attracted much attention for applications in disease prediction, health monitoring, robotic signal sensing, and curved surface temperature measurement. Preparing flexible temperature sensors with high sensitivity, fast response, wide temperature measurement interval, high flexibility, stretchability, low cost, high reliability, and stability has become a research target. This article reviewed the latest development of flexible temperature sensors and mainly discusses the sensitive materials, working mechanism, preparation process, and the applications of flexible temperature sensors. Finally, conclusions based on the latest developments, and the challenges and prospects for research in this field are presented.

The Mn_1.95−xCo_0.21Ni_0.84Sr_xO₄(MCNS) (0 ≼x≼ 0.15) based negative temperature coefficient (NTC) materials are prepared by co-precipitation method. The replacement of Mn by Sr plays a critical role in controlling the lattice parameter, relative density, microstructure, and electrical properties. The lattice parameter and relative density increase with the increase of Sr content. A small amount of Sr restrains the grain growth and increases the bulk density. Moreover, the room resistivityρ₂₅, material constantB_25/50, activation energyE_a, and temperature coefficientαvalues of MCNS ceramics are influenced by the Sr content and ranged in 1535.0–2053.6 Ω·cm, 3654–3709 K, 0.3149–0.3197 eV, and (−4.173%)–(−4.111%), respectively. The X-ray photoelectron spectroscopy (XPS) results explain the transformation of MCNS ceramics from n- to p-type semiconductors. The conduction could arise from the hopping polaron between Mn³⁺/Mn⁴⁺and Co²⁺/Co³⁺in the octahedral sites. The impedance data analysis also discusses the conduction mechanism of the MCNS ceramic, whereas grain resistance dominates the whole resistance of the samples. Furthermore, the aging coefficient (ΔR/R) of MCNS ceramics is found to be < 0.2%, which indicates the stable distribution of cations in the spinel. Finally, the MCNS ceramics demonstrate excellent thermal durability with < 1.3% of resistance shift after100 thermal shock cycles.