深紅與近紅外波段熱激活化延遲螢光材料有機發光元件研究

Abstract

有機發光二極體(organic light-emitting diode, OLED)比液晶顯示器LCD，有更佳的發光色彩，高對比度與應用在可彎曲面板的優勢。而OLED發光材料與元件結構有許多選擇。本篇論文主要研究利用熱激活化螢光(thermally activated delayed fluorescence, TADF)材料，製做出近紅外光波段具有高外部量子效率(external quantum efficiency, EQE)的OLED元件。 本篇論文的第一部分研究TADF材料TCN-TPA，具有多氰基的受體，採用真空蒸鍍法製作元件及薄膜，量測摻雜在mCPCN、CBP主體材料後的光物理特性，並選用CBP做為主體材料，做成元件後發光頻譜較紅移。透過TCN-TPA不同的摻雜濃度，薄膜PLQY可達5.7%~30.5%，元件在800 nm以上的近紅外光波段時，EQE可達到2.4%，在841 nm時EQE值則為1.1%。 本篇論文的第二部分研究TADF材料EP-TPA，其具有吡啶基的受體，外接吡啶。此材料採用旋轉塗佈方式製作元件及薄膜，透過試驗PVK、CBP與mCPCN等主體材料摻雜EP-TPA，量測不同的光物理特性，最後成功使用CBP摻雜12 wt.%的EP-TPA做出深紅光元件。

Organic light-emitting diodes(OLEDs) have better luminous color, higher contrast ratio and the advantages in applications of flexible panels in comparison with liquid crystal display LCDs. There are many options for OLED emitting materials and device structures. This thesis studies thermally activated delayed fluorescence (TADF) materials. Our goal is to make OLED devices with high external quantum efficiency (EQE) in the near-infrared band. The first part of this thesis studies TCN-TPA, which is a material containing more cyano group(-CN) to its accepter unit. Its photophysical properties after doping with the mCPCN and CBP host are characterized. Finally, CBP is selected as the host material for OLEDs because the emission spectrum in CBP is more red-shifted than in mCPCN. With different doping concentrations of TCN-TPA, it is found that the PLQY of the film can reach 5.7%~30.5%. When the device is in the near-infrared band above 800 nm, the EQE can reach 2.4%. The EQE value at 841nm is 1.1%. The second part of this paper studies the TADF material EP-TPA, which is a material containing external pyridyls to its acceptor. This material adopts the solution process to make the emitting film. Through the test of PVK, CBP and mCPCN as the host for EP-TPA, emitting photophysical properties were measured. Finally, CBP was successfully used as the host for EP-TPA to make the deep-red TADF OLEDs.