The Role of Thermal Energy in Carrier Detrapping and Mobility in ITO/PPV-D/Al Devices
DOI:
https://doi.org/10.66000/Keywords:
Charge transport, Effective mobility, Traps distribution, OLED devices, Thin filmsAbstract
The effect of temperature on the electrical properties of organic based electroluminescent structures is examined. For this purpose, thin film of organic light-emitting semiconductor (polyphenylenevinylene derivative – PPV-D) is deposited between indium-tin oxide (ITO) anode and aluminum cathode. DC current-voltage (I-V) characteristics of the fabricated devices ITO/PPV-D/Al are measured at varying ambient temperatures, ranging from room temperature (25oC) to 70oC. The measured characteristics are explained on the basis of the trapped space-charge-limited current theory. The predominant conduction mechanism is determined as a space-charge-limited conduction with an exponential trap energy distribution and field independent mobility in broad range of the applied voltage. Several important electrical parameters like a trap factor, free charge carriers’ density, trapped carriers density and effective mobility are estimated and discussed from observed temperature dependent I-V curves. It is shown that trap factor, effective mobility and free carriers density in the organic based structure increase non-linear with increasing the ambient temperature. Such analysis of the charge transport process in polymer devices may gives information needed for optimization of the existed structures.
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