The charge behavior of organic light emitting diode (OLED) is investigated by steady-state current-voltage technique and impedance spectroscopy at various temperatures to obtain activation energies of charge injection and transport processes. Good agreement of activation energies obtained by steady-state and frequency-domain was used to analyze their contributions to the charge injection and tr...

Metal oxides as ZnO provide an interesting alternative for conventional low work function metals as electron injection layer in organic light-emitting diodes (OLEDs). However, for most state-of-the-art OLED materials the high work function of ZnO leads to a large injection barrier for electrons. As a result the electron current in the OLED is largely limited by the contact, leading to a strong ...

Significant amount of emitted light from an organic light emitting diode (OLED) is trapped as a result of total internal reflection (TIR) on a glass–air interface. One of the strategies to increase the light extraction efficiency is using a scattering thin film. A model is built using the Monte Carlo ray tracing method to simulate Mie scattering. Almost 100% of light trapped by the TIR can be e...

The light extraction of OLED has been successfully enhanced by the combination of multi-cathode structure and high refractive index intermediate layer, which are introduced to control the surface plasmon coupling in the metal cathode and the distribution of optical energy in OLED, respectively. From the multi scale optical analysis, it was found that an approximately 70% of electromagnetic ener...

We have measured the ratio, r = sigma(S)/sigma(T) of the formation cross section, sigma of singlet and triplet excitons from polarons in pi-conjugated oligomer and polymer films, using a spectroscopic technique we developed recently. We discovered a universal relation between r and the conjugation length (CL): r(-1) depends linearly on CL-1, irrespective of the chain structure. Since r is direc...

We apply a rigorous dipole model to analyze the light outcoupling and angular performance of quantum dot light emitting diode (QLED). To illustrate the design principles, we use a red QLED as an example and compare its performance with an organic light emitting diode (OLED). By combining a high refractive index glass substrate with macroextractors, our simulation results indicate that the light...

Abstract MiniLED technology gives LCD panels a chance to stay in the race against OLED for high‐end applications—especially advanced TV market. However, cost may not always be competitive OLED.

We investigated the luminance enhancement, spectral shift and image blur of the OLED with the microlens array film (MAF) attachment experimentally and theoretically. Higher density, larger curvature, and smaller diameter of the microlenses extracted more light from the substrate mode. The maximum improvements of the luminance at the normal direction and the total power were 42.5% (80%) and 45% ...

A new voltage-programmed pixel circuit using soluble-processed organic thin film transistors (OTFTs) for an active matrix organic light emitting diode (AMOLED) is proposed. The proposed circuit is composed of four switching TFTs, one driving TFT and one storage capacitor, which is simulated by HSPICE. The proposed circuit can compensate for the non-uniformity of OLED current caused by the thres...