Host Material Based on Phenathrene Derivatives End-Capped with Pyrene Groups for Blue Organic Light-Emitting Diodes

• Main Authors: Sun, Yu Wen, 孫于雯
• Other Authors: Cheng, Chien Hong
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/a8z7s9

碩士 === 國立清華大學 === 化學系 === 105 === In the thesis, we used PPyP, PTP, TPyP, TTP as host materials doped with BCzVBi, TSTA, DPASP, and DMASP repectively, for the blue fluorescent emitters. With the suitable transporting materials and device layers, we have developed the deep-blue OLEDs with highly electrolu-minescence efficiency and long operation lifetime. Because the quantum yields of PPyP, PTP and TTP film doped with BCzVBi are above 90 % and TPyP film is also almost 90 %, energy transfer between host and dopant is efficient. Extraordinary external quantum efficiency (E.Q.E.) above 10 % is achieved in the device hosted by PTP, especially the DPASP-doped device 1T, showing the maximum E.Q.E. of 11.4 %, the current efficiency of 17.5 cd/A and the power efficie-ncy of 12.8 lm/W, the maximum luminescence of 91058 cd/m2, with the CIE coordinates of (0.14, 0.19). From the transient EL spectrum, we found that PTP-based devices showed the microsecond-scale delayed fluor-escence. Two triplet excitons formed a singlet exciton via triplet-triplet annihilation among excited PTP molecules, and singlet excitons were transfer to dopant for efficient delayed fluorescent. However, this is not the crucial reason why the E.Q.E. of device 1I、1P-1R exceeded the limited efficiency of fluorescent OLEDs. From the angle dependent p-polaried PL spectrum, the measurement reveals the transition dipole moments of the host materials doped with 5 % BCzVBi emitter is almost horizontal with a horiaontal factor