| 摘要: | 本計畫為”高效率電激發有機偏極子元件之研究”，重點為開發高外部量子效率的有機偏極子(polariton)發光二極體，並進行相關強耦合物理和發光機制之系統研究。由於電激發偏極子元件需要同時具備高吸收、發光、和導電特性的材料產生強耦合能態的電致發光，目前適合的有機材料不多，使電激發偏極子元件發展受到嚴重限制，至今發光效率仍遠低於一般OLED。本計畫研究的intracavity pumping元件結構，為在共振腔內結合強耦合材料(高吸收分子層)與弱耦合OLED，以強耦合材料產生polariton能態和弱耦合OLED激發polariton能態的發光，但隔絕強耦合材料與弱耦合OLED之驅動電流，使元件整體電致發光不受強耦合材料電性所影響。因此在材料選擇上比現有的偏極子元件更具彈性和變化性，可分別優化弱耦合OLED與強耦合材料，達到polariton發光的最佳效率。本計劃將研究一系列高發光效率的有機材料，進行弱耦合OLED的優化，可望大幅提昇目前有機偏極子元件的電致發光效率。同時也建立多功能即時角度解析光譜量測系統，進行電致發光、反射率、光致發光、和光致發光激發的量測，以研究polariton吸收、發光、和能量轉移等物理機制。相較於傳統光纖掃描的方式，此即時量測系統可大幅縮短元件驅動與量測時間，捕捉元件最佳效率狀態下的角度解析頻譜與光強資訊。利用元件結構優勢、不同材料的特性、和多功能角度解析光譜量測之技術，本計畫將深入探討偏極子電致發光效率之關鍵因素、釐清偏極子能量躍遷與散射機制、並研究載子對強耦合效應的影響，探索高密度偏極子的凝聚與發光現象。從研究過程中建立相關理論基礎和實驗技術，對於開發高效能強耦合元件和低閥值偏極子雷射將有重要的突破。 ;This project, Research on Electrically Pumped Organic Polariton Devices with High Efficiency, is to develop polariton OLEDs with high external quantum efficiencies, and to perform systematic studies on strong coupling physics and polariton emission. Electrically pumped polariton devices require materials with highly absorbing, luminescent and conductive properties to generate electroluminescence from polariton modes. However, so far the suitable organic materials are very limited, which severely influences the development of electrically pumped polariton devices, and the reported electroluminescent efficiencies are still much lower than general OLEDs. The studied intracavity pumping device structure combines a strongly-coupled material (highly absorbing molecular layer) and a weakly-coupled OLED in a microcavity, where the strongly-coupled material is for generation of polariton modes and the weakly-coupled OLED is to pump the emission from polariton modes. The strongly-coupled material is isolated from the current pathway of the weakly-coupled OLED, and hence its electrical property does not affect the electroluminescence of devices. Thus, compared to conventional polariton devices, our devices feature much more flexibilities and varieties on material selection, and possibilities to individually optimize the weakly-coupled OLED and strongly-coupled material to optimize polariton emission. This project will investigate a series of organic materials with high luminescence efficiency to optimize the weakly-coupled OLED, which is expected to significantly enhance the electroluminescent efficiency of polariton devices. This project will also establish a multifunctional one-shot angle-resolved spectroscopy system, capable of performing electroluminescence, reflectivity, photoluminescence, and photoluminescence excitation measurements, to study the mechanisms of polariton absorption, emission, and energy transfer. Compared to typical fiber scanning methods, this spectroscopy system takes much less time for driving and measuring devices, so that the angle-resolved spectra and intensities of polariton emission can be accurately acquired at optimal status. With the intracavity pumping device structure, different material properties, and the multifunctional one-shot angle-resolved spectroscopy technique, this project will investigate the critical factors on polariton luminescence, clarify the energy transfer and scattering mechanisms of polaritons, understand how charges affect the strong coupling effect, and explore polariton condensation and luminescence at high densities. The relevant theories and experimental techniques established in the research will provide significant breakthroughs in development of high-performance strongly-coupled devices and low threshold lasers. |
