Electrical characterization and parameters estimation of organic semiconductor, disperse orange dye 25 (OD) film at elevated temperature

In this paper the effect of temperature on electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin film of OD were deposited by 10% by wt. solution in distilled water on the cleaned surface of conductive glass (In₂O₃) substrates by spin coater at room temperature. Current-voltage characteristics (DC) of the samples (In₂O₃ / OD /Al) were measured in the temperature interval from 40 to 60°C. It was observed that the sample shows rectifying behavior particularly at relatively higher temperature. Conductivity of the samples was highly dependent on temperature. The charge transport process of organic semiconductor can be explained with trapped space charge limited current (TSCLC) model. It was found that temperature dependent current voltage characteristic can be divided into two regions, low temperature region and high temperature region. Entirely different conduction phenomena occurred at these two regions. Different electrical parameters such as trap factor, free carrier density, trapped carrier density, trap density effective mobility were determined from their temperature dependent I-V characteristics. It was also observed that when temperature increases then trap factor, effective mobility, free carrier density also increase, while trap density of state remains constant with temperature and trapped charge carrier density decreases with increase of temperature.