Organic and Hybrid Light Emission Devices Utilizing Delay Fluorescent and Quantum-Dot Emitter
|關鍵字:||延遲螢光;有機發光二極體;量子點;無機鹵化物鈣鈦礦;delay fluorescence;organic light emission diode;quantum dot;inorganic halide perovskite|
In this thesis, We studied the device engineering and photophysical properties of delay fluorescent materials, quantum dots and inorganic halide perovskite light-emitting devices. In the introduction, We briefly reviewed the applications and current development of organic light-emitting diodes (OLEDs) for solid-state lighting and display. In the second chapter, We reviewed the history of OLEDs, and their operating principles and measurement methodology. In the third chapter, We investigated two novel excimer-formation materials, and studied the characteristics of the excimer emission. Careful transient photophysical measurements revealed the exciton up-conversion from triplet states to singlet states. The excimer-base OLEDs were fabricated and optimized by judicious selection of the electron transport materials. The device showed an external quantum efficiency (EQE) up to 6.5%, which is higher than the theoretical efficiency of the conventional fluorescent OLEDs. In the fourth chapter, We measured the photoluminescence (PL) quantum yield of the quantum dots (QDs). And fabricated quantum dot light-emitting devices by blending QDs with Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) as an emission layer. Vertical phase separation between QDs and TCTA was observed .The device with lowest QDs concentration possessed the highest EQE of 0.62%. In the fifth chapter, We studied a series of thermally activated delayed fluorescence materials, of which the emission colors range from green to deep-blue. Large bandgap materials were selected as their host materials. We measured the temperature-dependent transient PL to analyze the delay fluorescence characteristics of these compounds. The efficient deep-blue OLEDs with International Commission on Illumination (CIE) coordinates of (0.18, 0.14) and a EQE up to 6.5% were demonstrated. In chapter six, Cesium Lead halide Perovskite films were deposited by dual source thermal evaporation. We further studied the charge transport and emission characteristics of Cesium Lead halide Perovskites. Finally, We demonstrated organic-inorganic hybrid light-emitting devices.
|Appears in Collections:||Thesis|