The Magnetoconductance Of The Organic Semiconductor Devices Under Illumination

The phenomenon is known as the current flows to the organic semiconductor device through the device under the action of an applied magnetic field change organic Magnetoconductance. No magnetic component in the device material and the devices exhibit magnetic phenomena, thus causing widespread concern in the scientific community. The same time, the organic material having a strong spin coherence, good flexibility, the characteristics of a variety of materials, the organic semiconductor device structure, the measurement conditions are varied, increasingly proficient film preparation process, such that the organic semiconductor device showing a broad application prospects.This paper studies the the magnetic conductance effect of organic semiconductor devices using molecular beam epitaxy and spin coating two coating growth both devices to study the behavior of devices exciton in the magnetic field in the laser light conditions,physical model reported in the literature to explain the possible physical mechanisms produce organic Magnetoconductance effect. In this paper, the main contents include the following sections:(1) Brief introduction to the research status of organic semiconductor devices, organic magneto-conductance effect the theoretical basis and organic Magnetoconductance effect; and introduced several physical model the existing organic Magnetoconductance mechanism; preparation of organic semiconductor devicesprocess and measurement techniques are described in detail.(2) By molecular beam epitaxial Preparation of the structure of a conventional organic semiconductor device ITO/CuPc/NPB/Alq3/LiF/Al, after the device using a wavelength of442nm and325nm, the laser beam is irradiated to generate excitons, andin a small bias (the device is not turned on) to control the evolution of the exciton, measuring devices at the same time light-induced magnetic conductance effect. It was found that, different from the electrical injection the exciton magnetic conductance effect, Magnetoconductance performance in the positive and negative bias significantly different magnetic response results. When the forward bias voltage to the device, the magnetic conductance of the device is rising rapidly in the range of0to40mT; with the further increase of the magnetic field, the magnetic conductivity increased slowly, and gradually become saturated. Reverse bias, the magnetic conductance of the device as the magnetic field is the first increases rapidly (0to40mT), but gradually decreases after reaching the maximum. Electron-hole by analyzing the impact of the external magnetic field on the device photo-generated carriers microscopic processes, the use of ’reverse bias’ model and the hyperfine interaction theory under forward bias magnetic conductivity better explained; for exciton and charge interactions due to the organic layer level to provide the necessary conditions for the use of triplet excitons and charge reaction mechanism can better explain the magnetic conductance decrease of high-field experimental phenomena.(3) By a spin-coating Preparation of a structure of ITO/PEDOT:the PSS/supper yellow-PPV/Ca/Al organic semiconductor device, in the laser light conditions and measured device Magnetoconductance effect. It was found that the light can significantly increase the conduction current of the device. Found that when using a smaller the conduction current measurement device Magnetoconductance effect increases rapidly as the absolute value of the current decreases, the absolute value of the conductance of the magnetic device. With the current conduction direction of the type of the device showing the type of positive linear approximation negative effect magnetoconductance the positive and negative bias magnetic conductance symmetrical. Compared device materials, structures and devices within the current transport properties of the relationship that the positive magnetic conductance under reverse bias hyperfine interaction principle and triplet excitons-the charge reaction mechanisms induced positive bias under negative magnetic conductivity and transport properties of the devices within the space charge limited current.