| 학회 | 한국고분자학회 |
| 학술대회 | 2004년 가을 (10/08 ~ 10/09, 경북대학교) |
| 권호 | 29권 2호, p.49 |
| 발표분야 | 분자전자 부문위원회 |
| 제목 | Exciton dynamics of pi-conjugated polymers for optoelectronic applications |
| 초록 | While the phenomenon of electroluminescence (EL) from organic, polymeric or small molecular light emitting diodes (LEDs) is qualitatively understood, a quantitative assessment of the microscopic processes is still sparse. One of these is the kinetics of the pathways by which the generated or injected excitations decay to the ground state. In a defect-free molecular system with balanced injection, sufficient to maintain a stationary concentration of both electrons and holes, the EL efficiency can be determined by the fraction of singlet excitations, or in the case of a phosphorescent emitter triplet excitations. Though, in a real world system there are inadvertently chemical and physical defects which can be populated by energy or charge transfer and which often catalyze non-radiative decay. In an LED, one would like to either eliminate these processes or exploit them via intelligent material design. Therefore, it is obvious that improving the performance of organic LEDs requires a quantitative understanding of the kinetic processes involved in order to avoid such a possible non-radiative decay. Since the elementary process of energy and charge transfer among nearest and non-nearest neighbour chromophores occurs on a time scale of typically ＜ 1 ps to several nanoseconds, fast fluorescence spectroscopy is the method of choice to characterize a given LED material. By comparing the spectroscopic behavior of various samples prepared by different ways, for instance, via varying of doping rate, one is able to delineate energy transfer to quantify the effect of those defects and extrapolate to the behavior of an ideal system. Fig. 1. Time-Resolved photoluminescence spectra of poly-paraphenylenevinylene derivative recorded with the streak-camera technique at RT and 4 K. References 1. C. Im, J.M. Lupton, P. Schouwink, S. Heun, H. Becker, and H. Bässler, Fluorescence dynamics of Phenyl substituted Polyphenylenevinylene - Trinitrofluorenone blend systems, J. Chem. Phys., vol. 117, no. 3, p. 1395, (2002). 2. C. Im, E. V. Emelianova, and H. Bässler, Intrinsic and extrinsic charge carrier photogeneration in Phenyl substituted Polyphenylenevinylene – Trinitro-fluorenone blend systems, J. Chem. Phys., vol. 117, no. 6, p. 2961, (2002). 3. J.M. Lupton, C. Im, and H. Bässler, Fast field-induced dissociation and recombination of optical excitations in a pi-conjugated polymer, J. Phys. D: Appl. Phys., vol. 36, no. 10, p. 1171, (2003). |
| 저자 | 임찬 |
| 소속 | 건국대 |
| 키워드 | pi-conj. polymers; energy transfer; LED; exciton dynamics; PPVs; PFs |
