Enhanced light emission from top-emitting organic light-emitting diodes by optimizing surface plasmon polariton losses

Article

关键词: EFFICIENCY ROLL-OFF;    DEVICES;    LAYER;    FLUORESCENCE;    ORIENTATION;    EXTRACTION;    ELECTRODES;    MODES;    OLEDS;    FILMS;   

DOI  :  10.1103/PhysRevB.92.245306

来源: SCIE

【 摘 要 】

We demonstrate enhanced light extraction for monochrome top-emitting organic light-emitting diodes (OLEDs). The enhancement by a factor of 1.2 compared to a reference sample is caused by the use of a hole transport layer (HTL) material possessing a low refractive index (similar to 1.52). The low refractive index reduces the in-plane wave vector of the surface plasmon polariton (SPP) excited at the interface between the bottom opaque metallic electrode (anode) and the HTL. The shift of the SPP dispersion relation decreases the power dissipated into lost evanescent excitations and thus increases the outcoupling efficiency, although the SPP remains constant in intensity. The proposed method is suitable for emitter materials having isotropic orientation of the transition dipole moments as well as anisotropic, preferentially horizontal orientation, resulting in comparable enhancement factors. Furthermore, for sufficiently low refractive indices of the HTL material, the SPP can be modeled as a propagating plane wave within other organic materials in the optical microcavity. Thus, by applying further extraction methods, such as microlenses or Bragg gratings, it would become feasible to obtain even higher enhancements of the light extraction.

【 授权许可】

Free