All-solid multi-environmental tolerant humidity sensors based on solution- processable large-area Au nanoparticles /black phosphorus composite thin film

Abstract

Humidity sensors are widely used in food processing, pharmaceuticals, climate control, drying, and creating specific living environments. They operate by selectively adsorbing H₂O molecules, inducing changes in electrical, optical, or mechanical properties to enable precise humidity detection. However, the sensitivity of humidity sensors exhibits apparent shifts under extreme environments, especially drastic temperature changes and intense light irradiation, due to the physical adsorption process of H₂O being easily affected. Herein, we fabricated an all-solid humidity sensor with a wide working temperature window by solution-processable large-area gold nanoparticles/black phosphorus (AuNPs-BP) composite thin film. As-fabricated devices exhibit a high sensitivity of up to 2000 % under 30°C temperature and 85 % relative humidity (RH). During continuous two-week humidity environment testing, the all-solid-state humidity sensor of AuNPs-BP composite thin film nanodevices demonstrate excellent long-term stability. Especially under some harsh conditions, including low temperature (15°C), high temperature (60°C), and intense light irradiation conditions from different wavelengths (532–1550 nm), the sensing performances have been well maintained. Therefore, the fabricated AuNPs-BP composite thin film devices can be applied in outdoor environmental monitoring and optical communication systems.