Energy Distribution of Trapping and Transport States in MDMO-PPV ([poly-(2-methoxyl, 5-(3,77dimethyloctyloxy)] Para Phenylenevinylene)
We have investigated charge carrier transport and trapping in the layers of [poly-(2-methoxyl, 5-(3,77dimethyloctyloxy)] para phenylenevinylene (MDMO-PPV). To reveal distribution of the trapping states the thermally stimulated current method was applied using the varying excitation conditions by light and applied voltage. To assure the selective excitation of the defect states close to the band gap edges, both extrinsic and intrinsic excitation by the light passed through the long-pass color filters with the cut-off energies ranging from 1.77 eV up to 3.1 eV was employed. Carrier transport conditions were varied by increasing applied electric field from 5 × 104 V/cm up to 6 × 105 V/cm. The effective thermal activation energy of material conductivity was dependent both on the spectral region of the exciting light and applied electric field. The superposition of several thermally activated processes, i.e., carrier generation from the trapping states and thermally stimulated mobility growth according to the Gaussian disorder model, was revealed. The energy distribution of the trapping state density was shown to follow the Gaussian distribution function. We had demonstrated that carrier trapping is effectively influenced by the extended defect states with the effective activation energy values ranging from 0.05 eV up to 0.15 eV with maximum located at about 0.07–0.08 eV. Moreover, deeper states with activation energies of 0.28–0.3 eV and 0.8–0.85 eV were identified. The results are direct indication by photo-thermo-electrical methods of distributed in energy trapping and transport states with the standard deviation of the density of states of about 0.015 eV.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 01 June 2012
More about this publication?
- Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Terms & Conditions
- Ingenta Connect is not responsible for the content or availability of external websites