ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Surface modification and characterization of h-BN-doped PVP thin film and its application as humidity sensor with theoretical DFT calculations

Laxmi Kumari, Utkarsh Kumar, Leena Sinha, Onkar Prasad, B. C. Yadav, and Manisha Gupta

Condensed Matter Physics Lab, Department of Physics, University of Lucknow, U.P, Lucknow, India

E-mail: guptagm@rediffmail.com

Received: 12 November 2020  Accepted: 15 March 2021

Abstract:

This paper presents the surface modification and characterization of h-BN-doped PVP thin film and its use as a humidity sensing probe. The thin film of h-BN-doped PVP has been prepared by spin coating method and characterized by XRD, SEM, TEM, UV–Vis, and FTIR spectroscopy. SEM and TEM images indicate that the PVP is densely packed with h-BN. The bandgap calculated by UV–visible spectroscopy varies from 4.9 to 5.2 eV on increasing the doping level. .The crystalline nature of the blend has been observed through X-ray diffraction spectrum with minimum crystallite size of 2 nm. The h-BN-doped PVP thin film was employed as a sensor with a sensitivity of 98.75 kΩ/%RH and 4.67 pF/%RH for impedance and capacitance, respectively. The minimum response/recovery time of the sensor (14/18 s) indicates that the blend can be used as a cost-efficient humidity sensor. Density functional theory (DFT) has been applied to simulate the adsorption of water molecules on the h-BN-doped PVP nanocomposite. The dipole moment, adsorption energy, and HOMO–LUMO gaps have been evaluated with increasing the number of water molecules. PDOS plots show alteration in the makeup of HOMO and LUMO on the adsorption of water molecules. MESP map illustrates the transfer of charge density from h-BN to the water molecules.

Keywords: XRD; SEM; TEM; UV–Vis; Humidity sensor; DFT

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01606-x

Chemical Papers 75 (8) 4055–4068 (2021)