Design Of Time-resolved Spectroscopy System Of Organic Light-emitting Device

In recent years, OLED(Organic Electroluminescent Device) study on the technical and commercial progress have a far-reaching impact. With the traditional display compared Organic Electroluminescent Device obviously is starting with low voltage, high efficiency, and high brightness, the thickness of thin and bending performance advantages such as relatively good, its application is a very attractive prospect. Once its brightness, efficiency and service life, and other problems are resolved, will be in the civil and military fields to be widely applied. As a solid source, a low-voltage drive OLED, small lightweight, long-life characteristics.White organic electroluminescent light source, like paper, can be arbitrary bending and can be used as display devices dashboard light. So far, however, OLED stability still exists poor, making it difficult to real applications. At present, many scientists to the focus of the study has been put on improving the stability, the stability once the issue is resolved, organic thin film electroluminescent will be promising.Today's time-resolved spectroscopy in many ways been a very good application. Photophysical such as research, photochemical and biological rapid-change process in conjunction with the fluorescence quantum yields from life in the excited state dynamics can be an important parameter, such as the excited state radiative transition and non-radiative transition rate constant; detection of biological macromolecules structural changes; of energy transfer and molecular activity of the molecules or groups of the gap interaction, or complex dimer formation in conjunction with fluorescence polarization spectroscopy of biological macromolecules can speculate the shape, size, as well as in solution rotational relaxation time.To measure organic thin film electroluminescent devices'luminous efficiency and the fluorescence characteristics parameters produced by the laboratory, support for the research work of organic light emitting devices. Based on the inspection of the OLED and time-resolved spectroscopy aspects relevant information, designed for organic thin film electroluminescent device of time-resolved spectroscopy system, the spectral measurement system is the main access to the organic light-emitting device for the purpose of fluorescence decay curves , obtained by curve fitting its fluorescence lifetime doping concentration by comparing different organic light-emitting materials such devices to evaluate the performance of the LED, for the production of higher-efficiency organic light-emitting device provides criteria.In order to get organic light-emitting devices transient spectroscopy, we first designed a nanosecond pulse circuit, in order to encourage organic light-emitting device to luminescence. In this section, nanosecond pulse circuit design to the existing research results, based on the principle of its work and output waveform parameters, in order to meet the requirement of experiment, according to the existing experimental environment, the use of the avalanche transistor at the core 3DB2J device, circuit structure and carried out a series of simplified, first produced in the pulse width of about 40 ns pulse. But this has not reached the experimental requirements, the final use of high voltage power supply modules to enhance avalanche transistor into the avalanche critical state, so that the signal generator as a square wave signal input excitation signal circumstances, we can obtain output rise time of less than 2ns, less than 10 ns pulse width of the super-narrow pulse. In order to be more narrow pulse energy, pulse duration must be widened so that the design of a variable capacitor switching circuit, thereby increasing the capacity of the output capacitor value, have been able to encourage organic light-emitting devices narrow pulse.Secondly, in the circuit design is completed after the excitation source, the paper for the time-resolved spectroscopy system design were discussed under pulsed fluorescence method based on phase-shifting and time-resolved fluorescence spectra of the basic theory, the two mainstream of the current time-resolved spectroscopy TCSPC stroscopic technology and technology carried out in-depth analysis to determine the organic light-emitting device to measure the attenuation curve of the time-based system of time-resolved spectroscopy. Macromolecular system by studying the actual fluorescence anisotropy decay curve can be related to macromolecular conformation and size of the flexible chain of information. Excited state dynamics analysis is to understand Photophysical, photochemical and biological processes-an important means of the core through the different levels of electrons in the transition rate to understand the physical process. All on a level to the next level of the transition rate and the total level as the transition rate, which is the level of its countdown of life, does not contain non-radiative transition rate of circumstances, also known as fluorescence lifetime . Experiment on the life of the excited level measurement means, including pulsed fluorescence and fluorescence of the two phase-shift method, the basic tenets are on the level by measuring the fluorescence decay to obtain samples of the excited state lifetime (or obtain samplesδexcitation function of the decay response parameters). Pulsed fluorescence method is through a very short period of direct excitation pulse excitation sample excitation pulse duration far smaller than the life-energy, we can approximate that the response shall be in samplesδexcited by the attenuation function curves, when excitation pulse and the order of magnitude closer to the life-energy, through deconvolution method real excited functionδattenuation curve. After obtaining the attenuation curve, rate equations can be used with the theoretical analysis on the energy of the excited state response curve fitting experimental results, which are life-energy of the excited state parameters, then from the perspective of luminescence dynamics of the process for further analysis. Phase shift fluorescence law through a different frequency and amplitude modulation excitation light to obtain material harmonic response, orδexcitation response function of Fourier transform. Usually, we also called pulsed fluorescence time domain analysis, phase shift assay for frequency-domain analysis. Similarly fluorescence intensity decay curve also contains very useful information. For example, polymer synthesis and biological macromolecules in solution often with a variety of different conformation, and therefore the corresponding fluorescence decay should show more exponential form. Using time-resolved fluorescence anisotropy studies for the donor and acceptor energy transfer, not only can be energy transfer efficiency, but also revealed receptors in the body for the distribution of forms around. Using time-resolved fluorescence technique can reveal fluorescence quenching is a free proliferation control or specific binding control. In fact many elements or elements within the weak interaction information, particularly dynamic information, and only through time-resolved fluorescence technique can be.We use the monochromator the laboratories provided by the OLED samples: 2 - methoxy-5 - (2 - ethylhexyl) -1,4--1,4 - benzodiazepine (ethylene MEHPPV) emitting layer, respectively doped 0.05% and 0.12% of the ferromagnetic material CoPt the system its fluorescence decay curves of the survey work at 440 nm, 500nm and 550nm wavelength . Under these high-performance curve for organic light-emitting device research provides a wealth of information to fluorescent substances and doping substances selection and experimental comparison.