Humidity Sensors Realized via Negative Photoconductivity Effect in Nanodiamonds

Herein, the negative photoconductivity (NPC) effect has been observed in nanodiamonds (NDs) for the first time, and with illumination under a 660 nm laser lamp, the conductivity of the NDs decreases significantly. The NPC effect has been attributed to the trapping of carriers by the absorbed water molecules on the ND surfaces. A humidity sensor has been constructed based on the NPC effect of the NDs, and the sensitivity of the sensor can reach 10(6)%, which is the highest value ever reported for carbon-based humidity sensors.

Automated summary

The negative photoconductivity effect has been observed in nanodiamonds for the first time, attributed to carriers being trapped by absorbed water molecules on the ND surfaces under 660 nm laser illumination. A humidity sensor was constructed based on this effect, with a sensitivity reaching 10^6%, the highest reported for carbon-based humidity sensors.