Electrical and Optical Properties of Thin Film and Superlattice Structure Utilizing Conducting Polymers and Their Application for Luminescent Devices

讨论了有机多量子阱(MQW)结构的电致发光(EL)特性和量子尺寸效应。讨论了有机多量子阱系统独特的电致发光光谱和偏振特性。1)铝喹啉(Alq_3)/芳香族二胺(TPD)MQW体系发生了能量转移，其中Alq_3层在短周期MQW结构中观察到了较强的光致发光(PL)。在短周期多量子阱结构中，由于量子尺寸效应，发光能量向高能方向移动。2)在Alq3/TPD多量子阱系统中施加反向偏置电场，使发光强度猝灭。3)环戊二烯衍生物(PPCP)/芳香族二胺(TPD)MQW结构的发光光谱显示出PPCP的发射峰，由于MQW系统的光谱不依赖于激发光，因此解释了TPD到PPCP的能量转移，激子被限制在PPCP层中。4)具有PPCP/TPD MQW结构的二极管的电致发光光谱仅来自PPCP除了PPCP原有的发射外，还观察到了新的较长波长的发射，这是由薄层之间的相互作用或界面引起的，并且在该体系中各层之间的相互作用很强。TE模具有较短的波长分量，TM模具有较长的波长分量。

Novel electroluminescent (EL) characteristics and quantum size effects in organic multiple quantum well (MQW) structure have been discussed. Unique EL spectrum and polarization characteristics have been discussed in organic MQW systems. The experimental results are summarized as follows.1)Energy transfer has been observed in aluminum quinoline (Alq_3) /aromatic diamine (TPD) MQW system, where the strong photluminescence (PL) emission has been observed from Alq_3 layr in the short-period MQW structure. PL energy shift to higher energy side has been observed in the short-period MQW structure, which is caused by quantum size effect in the MQW structure.2) The PL intensity is quenched by applying reverse biased electric field to the Alq_3/TPD MQW system. The quenching is strong in the short-period structure, where the extraction of exciton is strong due to the strong electric field in the Alq_3 layrs.3) The PL spectrum with cyclopentadiene derivatives (PPCP) /aromatic diamine (TPD) MQW structure exhibits a peak emission from PPCP.Since the spectrum of the MQW system does not depend upon the excitation light, it is interpreted that the energy transfer from TPD to PPCP has been conducted and the excitons are confined in the PPCP layr.4) The EL spectra of the diodes with PPCP/TPD MQW structure exhibits only from PPCP.In the short-period stucture, newly created emission at longer wavelength is observed besides the original emission of PPCP.This is caused by the interaction or the interface of the thin layrs, and the interaction between the layrs are strong in this system. TE mode has the shorter wavelength component and TM mode the longer one.