Characterization of thermally evaporated 1,8-diacetoxy-9,10-anthraquinone films

Abstract

The compound 1,8-diacetoxy-9,10-anthraquinone has been synthesised. Thin films coatings of this material have been prepared by thermal evaporation on glass substrates at different temperatures in vacuum. The experimental conditions have been optimised to obtain better crystallinity of the films. The films prepared thus have been studied for their structural, electrical and optical properties. The comparison of infrared (IR) and nuclear magnetic resonance (NMR) spectra of 1,8-diacetoxy-9,10-anthraquinone and its films shows that the compound remains unaffected during vacuum deposition and annealing processes. Observations reveal that the crystallinity of the films increases at higher substrate temperatures. Grains as large as 3.16 μm are observed in the case of films deposited at 333 K. The current–voltage characteristics of these films show ohmic behaviour of conduction within the investigated field and temperature range (10–60 V, 290–410 K). The conduction appears to take place by thermally activated hopping above intermolecular barriers. The electrical conductivity and carrier concentration of films also increases at higher substrate temperatures. Analysis of optical absorption measurements on the films indicate that the interband transition energies lie in the range 2.80–3.43 eV.