Evaluation of subband energy in TPD/DCM organic multiple quantum wells

摘要

In this paper, we report fabrication and evaluation of an organic light emitting diode (OLED) with organic multiple quantum wells (OMQWs). We fabricated the OMQWs using organic molecular beam deposition, consisting of TPD (N,N'-bis(3-methilphenyl)-N.N-diphenyl benzidine) and DCM (4-(Dicyanomethilane)-2-methil-6-(p-dimethilamino-styryl)-4H-pyran). We measured photoluminescence (PL) and electroluminescence (EL) properties to characterize the OMQWs. In both measurements the peaking wavelengths clearly become shorter as the thickness of the QWs becomes narrower. This result obviously indicates that subband states are achieved in the quantum wells. In addition, we did numerical analysis to assign the effective mass of electrons in the OMQWs. Consequently, the effective mass of electrons can be estimated as 0.05 m_0.