Charge injection and transport properties of an organic light-emitting diode

The charge behavior of organic light emitting diode (OLED) is investigated by steady-state current–voltage technique and impedance spectroscopy at various temperatures to obtain activation energies of charge injection and transport processes. Good agreement of activation energies obtained by steady-state and frequency-domain was used to analyze their contributions to the charge injection and transport. We concluded that charge is injected into the OLED device mostly through the interfacial states at low voltage region, whereas the thermionic injection dominates in the high voltage region. This comparison of experimental techniques demonstrates their capabilities of identification of major bottleneck of charge injection and transport

Visible Light Photodiodes and Photovoltages from Detonation Nanodiamonds

International audienceMacroscopic and microscopic photovoltage characteristics of detonation nanodiamonds (DNDs) with distinct surface terminations are presented. Organic photodiodes are fabricated based on P3HT+DNDs mixture (50 wt%). We compare effect of hydrogen and oxygen termination of DNDs. Compared to photodiodes without DNDs the current-voltage characteristics of photodiodes with O-DNDs in dark and under AM 1.5 illumination show reduced dark current, and higher photocurrent and open circuit voltage. H-DNDs shunt the photodiodes, which is attributed to their surface conductivity. Kelvin probe force microscopy detects a reproducible photovoltage of around 5 mV generated by a green laser (532 nm) on both types of pristine DNDs. Thus although conductivity of H-DNDs may represent a problem for photodiodes, both types of DNDs alone can function as miniature energy conversion devices

Improved Tolerance against UV and Alpha Irradiation of Encapsulated Organic TFTs

The aim of this work is to investigate the effects of the encapsulation on the robustness against ionizing radiation on organic thin-film-transistors. We analyzed the UV and alpha radiation effects on the threshold voltage, the hole mobility and interface traps

Stimulated Emission from InAs (GaAs) Monolayers Stacks Embedded in Al0.33Ga0.67As Ective Region

Our study is focused on the optical and electronic properties of InAs (GaAs) monolayers embedded in Al0.33GA0.67As barrier layers investigated by temperature dependencies of electroluminescence spectra. The experimental results obtained from low temperature electroluminescence measurements of InAs (GaAs)/Al0.33GA0.67As revealed the excellent emission spectra in the visib le range 630-690 nm. The stimulated emission from these structures across their cleavage planes has been observed at low  temperatures what is highly interesting for potential device applications