Optical absorption studies on 1,4-/1,8-dihydroxy-9,10-anthraquinone films

1,4-Dihydroxy-9,10-anthraquinone and 1,8-dihydroxy-9,10-anthraquinone films have been grown by thermal evaporation technique onto the glass substrate kept at different temperatures in a vacuum of 10(-5) torr. The experimental conditions are optimised to obtain better crystallinity of the films, The films so prepared have been studied for their optical properties in the wav elength range 300-800 nm. Observations reveal that the optical band gap of the films increases with increase in substrate temperature and lie in range of 1.6-2.36 eV. The extinction coefficient (k) and refractive index (n) of films have also been calculated.