Bimetallic MoNi/WNi nanoalloys for ultra-sensitive wearable temperature sensors

Abstract

Continuous real-time monitoring of temperature has played an essential role in human health. Herein, we fabricated an all textile-based temperature sensor using nickel-molybdenum (MoNi) and tungsten-molybdenum (WNi) bimetallic nanoalloys, which exhibits high sensitivity and flexibility with a negative temperature coefficient (NTC). This is the first report of tetragonal phase MoNi₄ and WNi₄ nanoalloys in temperature sensing. The nanoalloys possess exceptional sensing performance, with nearly four orders of resistance variation from 25 to 330 °C, constant of thermistor B = 10 890 K (25–40 °C), and rapid response, endowing temperature sensors with promising application respiratory monitoring. Flexible respiratory sensors can still work under high humidity conditions (>95 RH%) without sacrificing accuracy and sensitivity. Besides the superior performance, the sensor possesses great practical potential with simple preparation, low cost and high stability. A potential application has been demonstrated in transmitting information by blowing the sensor according to Morse code, which can help people in a special environment to send information. It is believed that the bimetallic nanoalloy-based temperature sensors will hold great applications in flexible wearable devices.