Morphology characterization and humidity measurement data of PEO/ZnO sensor

Scanning electron microscopy (SEM, Germany-ZEISS sigma500) was used to characterize the morphology and microstructure of the samples. X-ray diffraction (XRD, Bruker D8 Advance, Bruker, Karlsruhe, Germany; Cu Kα radiation, λ = 0.154 nm) was used to characterize the phase composition of the samples. Fourier-transform infrared spectrometry (FTIR, Shimadzu-IRTracer 100, Japan) was used to measure the functional groups of the samples. Elemental analysis of the sample was performed using X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi, Thermo Fisher Scientific, USA) with an Al Kα source of 1486.6 eV.The humidity performance test used a saturated salt solution of LiCl, MgCl2, K2CO3, Mg(NO3)2, NaCl, KCl, and KNO3 to provide environments with a humidity of 11% RH, 33% RH, 43% RH, 59% RH, 75% RH, 85% RH, or 95% RH, respectively. The performance of a humidity sensor operating at 1 V and operating at a frequency range of 40 Hz to 100 kHz at room temperature (RT) was tested using a Zennium workstation (CIMPS 2, Zahner).