Snapshot Angle-Resolved Spectroscopy and Its Application for Study of Highly Efficient Polariton OLEDs

Jui-Fen Chang,Yi Chen,Yan-Rong Huang,Guo-Sian Ciou,Shun-Yu Hong,Chung-Ken Lin

doi:10.3390/cryst11121553

Abstract

The multifunctional snapshot angle-resolved spectroscopy (ARS) system capable of electroluminescence, photoluminescence, and reflectance measurements for thin film devices is developed based on the k-space imaging technique. Compared with the conventional goniometric ARS system, this snapshot spectroscopy system offers great advantages of rapid and simple measurement, suitable for characterizing thin film devices that are unstable or degraded under long-time or high-power driving conditions, such as OLEDs. We perform a detailed calibration of the snapshot system and show that the measured results closely match with those obtained using a goniometric system. Furthermore, we show the capabilities of the system with application in studying polariton OLEDs. The result provides comprehensive information on the polariton mode dispersion and emission distribution, and shows an effective radiative pumping of the lower polariton branch for high emission efficiency.

Highlights

In the past decades, there has been tremendous progress in the research of organic lightemitting diodes (OLEDs) for display applications, which offer great advantages of high brightness, large contrast, and a wide viewing angle [1,2,3]
Based on the k-space imaging technique, here we present a multifunctional snapshot angle-resolved spectroscopy (ARS) system for measuring electroluminescence (EL), photoluminescence (PL), and reflectance spectra of thin film devices such as OLEDs
We have developed a multifunctional snapshot ARS system that enables simple and instant measurements on the EL, PL, and reflectance of thin film devices

Summary

Introduction

There has been tremendous progress in the research of organic lightemitting diodes (OLEDs) for display applications, which offer great advantages of high brightness, large contrast, and a wide viewing angle [1,2,3]. The ARS systems based on the k-space (momentum space) imaging technique have been developed for numerous types of research work [11,12,13,14,15] In these systems, the emission or reflected/transmitted light from the sample is collected by a microscope objective and Fourier-transformed into a far-field image in the Fourier (back focal) plane of the objective, which corresponds to the spectral information at specific angles and can be imaged onto a camera spectrometer to perform ARS measurement with a snapshot, thereby minimizing the errors caused by device instability or degradation over the measuring time.

Angle-Resolved Spectroscopy Setup and Calibration

Characterizations of Polariton OLED

Findings

Conclusions