Flexible plasmonic random laser for wearable humidity sensing

Humidity sensing plays an important role in the professional field and our daily life, such as chemical preparation process, environmental monitoring, and food storage. Herein, a wearable humidity sensor is designed based on a flexible plasmonic random laser. The random laser-based humidity sensor is fabricated by transferring an ultrathin light-emitting polymer membrane doped with silver nanoparticles onto the humidity-sensitive PEDOT:PSS film. Under optical pumping, random lasing with low-threshold is achieved, assisted by the strong plasmonic feedback of the silver nanoparticles. The random laser-based humidity sensor exhibits a good linear response with a coefficient of 0.997. Comparing with the emission intensity at initial relative humidity (RH) (34.8%), the peak intensity increases 5.5 times at an RH value of 93.5%. This phenomenon mainly results from the ambient, humidity-sensitive relative refractive index difference between polymer membrane and PEDOT:PSS film. The random laser-based humidity sensor is flexible and nontoxic, which can be transplanted easily to achieve wearable laser devices.

Automated summary

The wearable humidity sensor designed based on a flexible plasmonic random laser demonstrates a low-threshold random lasing with the assistance of silver nanoparticles, showing a good linear response. The peak intensity increases significantly as the relative humidity value rises, making it suitable for wearable laser devices.