Studies On The Magnetic Field Effects In Organic Optoelectronic Devices

The magnetic field effects in organic optoelectronic devices including current and light-emitting magnetic effect (i.e., magnetic conductivity and magnetic-induced light-emitting effect), refers to the phenomenon of conduction current of the device or the luminous intensity changes in the magnetic field. It was found that in the conventional organic optoelectronic devices, although there is no magnetic component, there is a huge magnetic response. This strange phenomenon has aroused great concern in the scientific community. For its potential commercial value, many companies, enterprises continue to increase investment on the research and development of the organic magnetic effect. Through the joint efforts of the scientific community and industry, the organic optoelectronic devices and organic magnetic effect has entered the pre-commercial applications. A large number of theoretical results continue to emerge, including a large number of different linear or value of different organic field effect, as research continuously carried out, it was found that the type of organic material, the type of thin film growth, the type of device structure, etc., the type organic field effect can be obtained. This regard to the effect of organic field production has brought some difficulties; on the other hand also let people see the final regulation on organic magnetic effect made possible through the use of different ways. For organic magnetic effect has not yet formed a unified theoretical point of view, for different magnetic effect, the researchers have proposed the corresponding theoretical models, such as the hyperfine interaction model, triplet exciton-the charge response model (TQA), the triplet-triplet exciton annihilation model (TTA). Overall, organic magnetic effect has made great progress, but from a full commercial application there is a big gap, but also the need for further experimental and theoretical studies.This paper studies the rubrene material as a light-emitting material, the magnetic effect of the organic optoelectronic devices, including the magnetic luminescent effect and the magnetic conductance effect. The study found that the rubrene-based organic photovoltaic device, regardless of the magnetic luminescent or magnetic conductance appears is different from the organic optoelectronic devices based on Alq3. It is believed that through the analysis in the rubrene (such organic aromatic) material, the characteristic of the material itself is easy to produce another physical mechanism, namely:singlet exciton fission (STT) mechanism. This article gave a detailed explanation of this phenomenon and the physical mechanism, the explanation on the TTA and STT role process there may be different effects on the OLED magnetic effect. This study includes the following:(1) Using the organic molecular beam epitaxy (MBE), co-evaporated, the thermal resistance was evaporated, and the substrate-cleaning,the organic photovoltaic device which is the reference device and the rubrene device has been prepared by means of preparation OLED technology. By using the external magnetic field, the triplet-triplet exciton quenching process and singlet exciton fission process of these devices has been discussed; the experimental results are explained qualitatively.(2) The organic light-emitting diodes with a thin rubrene layer were fabricated. The magnetic field effects on electroluminescence (MEL) were investigated under different temperatures (15K≤T≤300K). Results show that the line shape and the magnitude of the MEL in rubrene-based devices are different in comparison with the reference devices. For the reference devices, the MEL increases sharply in the low-field but saturates slowly in the high-field at room temperature. However, for the rubrene-based device, the magnitude of the MEL is suppressed in the iow-field range but continues to increase in the high-field. Moreover, those properties of the MEL show temperature dependence. Red shift with decreasing temperature is also observed from its spectrum. A composite model has been proposed based on the hyperfine interaction, the magnetic field-mediated singlet exciton fission process (STT) process and the triplet-triplet annihilation process (TTA). We suggested that, at room temperature, the MEL behaviors of rubrene-based devices are contributed to the hyperfine interaction and STT process, while hyperfine interaction and TTA process are dominated at15K.(3) By research on magneto conductance of rubrene-based device which structure is ITO/CuPc/NPB/rubrene/BCP/LiF/Al. Compared to the reference device, the magneto conductance performance of the rubrene device in the external magnetic field is that:first, take a quick rise in the low magnetic field, when the magnetic field reach of～10mT begin to decline, then turned to increase when the magnetic field reach of～100mT, but within the measurement range does not reach saturation. We suggested that the magneto conductance behaviors of rubrene-based devices are contributed to the hyperfine interaction and STT process, (4) The research development of "A high magnetic response of the organic light emitting diode "(Patent No.:201110269411, discloses (Notice) Date:2011.12.21), the organic light emitting diode device has a relatively high value of the magnetically responsive and does not sensitive to the temperature. It can be used to detect the presence of weak external magnetic field and its characteristics change by the characteristic curve of the magnetic effect of the organic light emitting diode...