Development of a Temperature Sensor Using Spin-Crossover Fe(pyrazine)[Pt(CN)(4)I] Nanoparticles

Abstract

Device miniaturization requires temperature sensors with high resolution and precise calibration for measurements at reduced scale. We developed an optical temperature sensor using Fe2+ spin-crossover (SCO) material that has low and high spin states depending on temperature. We adjusted the operating range of the SCO (295-365 K) with an appropriate concentration of iodine. The color induced by temperature change was observed with a microscope and was converted to the color intensity represented in grayscale. To test the material, we covered the surface of a gold microheater with a layer of Fe(pyrazine)[Pt(CN)(4)I] SCO nanoparticles and compared optically measured temperatures with those from a conventional temperature sensor. We conclude that the thermochromic temperature sensor is suitable for measuring temperature changes in microdevices, even in ambient light.