Surface Topography, Absorption, and Fluorescence Characteristics Tuned by UV Exposure and Thermal Annealing of a...

Thin films of DPP were synthesized by thermal deposition technique. The films were treated by exposure to ultraviolet irradiation or thermal annealing. Surface topography of the DPP films was examined by atomic force microscopy technique. DPP films were found to have a very smooth surface after treatment by both ultraviolet irradiation and thermal annealing. The optical absorption analyses were assessed by ultraviolet-visible spectroscopy. The influence of ultraviolet irradiation and thermal annealing on the band gap and Urbach's energy was investigated. The emission characteristics of DPP films were also investigated along with the effects of ultraviolet irradiation and thermal annealing on them. DPP films showed fluorescence emission spectra with emission maxima at around 500 nm. The emission peak was decayed by the effect of ultraviolet irradiation and thermal annealing. The color coordinates of the emission spectra were assessed by a color calculator program, and it revealed that the color coordinates changed as an effect of treatment to the DPP films. The investigated results suggest DPP as a good optoelectronic material that can be applied in sensor applications.