Edge-on orientation of thermally evaporated metal phthalocyanines thin films for humidity sensing application
Document Type
Article
Publication Date
3-1-2024
Abstract
Thermally evaporated metal phthalocyanines (MPcs) were successfully fabricated for humidity-sensing applications. Comparative molecular analysis of three different MPcs sensing layers, namely MnPc, VOPc, and VTTBNc, using the powerful tool of grazing-incidence wide-angle and small-angle X-ray scattering (GIWAXS/GISAXS), were made to find the correlation between molecule orientation of the sensing layers and their humidity sensing performances. In this study, planar-configurated capacitive Al/MnPc/Al humidity sensor produced the highest sensitivity (17.74 nF/%RH) relative to Al/VTTBNc/Al (11.50 nF/%RH) and Al/VOPc/Al (11.20 nF/%RH) due to its crystallographic orientation being more vertical than the VTTBNc and VOPc counterparts, as confirmed by GIWAXS and GISAXS analysis. Similarly, the MnPc-based sensor produced the fastest response and recovery time of 3 s and 2 s, respectively. Meanwhile, VTTBNc yielded the smallest hysteresis gap of 0.29%. The quantitative and qualitative information, such as crystal coherence length, grain size, and lattice spacing obtained from the GIWAXS and GISAXS, have been studied to explain the humidity sensors' sensitivity, hysteresis, and transient response. The crystallographic orientation of the active sensing layer significantly influences the humidity sensing performance.
Keywords
Performance, Microstructure, Acceptor, Sensors, Size, Cell
Divisions
PHYSICS
Funders
Advanced Light Source (DE-AC02-05CH11231),United States Department of Energy (DOE),IUPAP-IUCr-ICTP LAAAMP
Publication Title
Journal of Materials Science: Materials in Electronics
Volume
35
Issue
7
Publisher
Springer
Publisher Location
VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS