Direct visualization of trapped carrier in organic light-emitting diodes by using electric-field-induced optical second-harmonic generation measurement, and its application to degradation analysis

2016 Fiscal Year Final Research Report

• Project/Area Number: 25709022
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Electronic materials/Electric materials
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Taguchi Dai 東京工業大学, 工学院, 助教 (00531873)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 誘電物性 / 解析・評価 / トラップ / 可視化 / 光第2次高調波発生 / 電子デバイス・機器 / 電子・電気材料 / 電界

Outline of Final Research Achievements

By using electric-field-induced optical second-harmonic generation (EFISHG) measurement, an experimental method for directly visualizing trapped carrier in organic light-emitting diodes was investigated. For real space visualization, we freshly developed axially polarized EFISHG microscope and CCD imaging-type EFISHG system. These systems allow one to visualize carrier behaviors in milli- to micro-meter area. Results showed carrier behaviors leading to degradation phenomena such as electrical breakdown, 1: voltage dependent carrier trapping, 2: time-dependent pulse-like carrier injection, and 3: development of inhomogeneous carrier distribution. The energy states of carrier traps were analyzed by means of optical excitation, thermal excitation, and electroluminescence.

Free Research Field

電子・電気材料工学