Saturated Salt Hydrogel Engineering for Tunable ZnO Ultraviolet Sensor Performance and Mitigated Humidity
Yunfu Cui1, Li Cheng1, Bolang Cheng2
1School of Materials and Energy, Lanzhou University, Lanzhou, Gansu 730000, China.
ACS Applied Materials & Interfaces
|January 9, 2026
Summary
This study reveals how humidity can enhance zinc oxide (ZnO) ultraviolet (UV) sensors. A novel hydrogel-modulated sensor overcomes humidity interference, improving UV detection reliability and performance.
Area of Science:
- Materials Science
- Chemical Engineering
- Sensor Technology
Background:
- Humidity typically degrades zinc oxide (ZnO) ultraviolet (UV) sensor performance by interfering with oxygen adsorption.
- This interference compromises the reliability of UV detection in environmental monitoring applications.
Purpose of the Study:
- To investigate the competitive adsorption mechanisms of water (H2O) and oxygen (O2) on ZnO surfaces.
- To develop a novel ZnO UV sensor that utilizes humidity as a performance-regulating factor, overcoming its detrimental effects.
Main Methods:
- Systematic elucidation of competitive adsorption mechanisms between H2O and O2.
- Development of a saturated salt hydrogel-modulated ZnO UV sensor (SSHM-ZnO-UVS).
- Evaluation of sensor performance under varying relative humidity levels (15% to 89%).
Main Results:
- The SSHM-ZnO-UVS demonstrated suppressed humidity-dependent photoresponse, with limited fluctuations in response, response time, and recovery time (1.09%, 4.36%, 4.36%).
- The sensor enabled tunable trade-offs between response speed and sensitivity.
- Achieved ultrafast operation (1.8 s response, 1.4 s recovery) or high sensitivity (on/off ratio of 1.6 × 10^4).
Conclusions:
- Humidity can be engineered as a functional regulator to enhance ZnO UV sensor performance.
- The developed SSHM-ZnO-UVS strategy offers a generalizable approach for improving UV sensor reliability and tunability.
- This research transforms a known limitation into an advantage for advanced UV sensing applications.
