- 标题
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Suppression of device degradation mechanism by triphenylsilyl group substitution of the host for blue phosphorescent organic light-emitting diodes
摘要： The effect of triphenylsilyl group substitution in the host materials for blue phosphorescent organic light-emitting diodes was studied by synthesizing two hole transport type hosts with and without the triphenylsilyl group in the identical backbone structure. The two host materials were applied as the hosts of blue phosphorescent emitter and the comparison of the emission behavior of the two hosts revealed that the triphenylsilyl group suppressed triplet exciton quenching of the blue phosphorescent emitters. As a result, the blue host with the triphenylsilyl group showed improved device efficiency and extended device lifetime in the blue phosphorescent devices. The blue phosphorescent device with the triphenylsilyl group substituted host showed improved external quantum efficiency and elongated device lifetime compared to the triphenylsilyl free host based device. The bulky triphenylsilyl group was effective to extend the device lifetime of the blue phosphorescent device through reduced triplet exciton induced annihilation.
关键词： host,blue device,device lifetime,phosphorescent host
更新于2025-09-19 17:13:59
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Novel Carbazole/Fluorene-Based Host Material for Stable and Efficient Phosphorescent OLEDs
摘要： A novel host material of "M"-type carbazole/fluorene-based mDCzPF with a high triplet energy by utilizing meta-substituted phenyl groups as linkers was developed. It was demonstrated that the position of the substituents significantly affected the molecular configuration and dipole moment, which played a critical role in the device performances. Red phosphorescent OLED utilizing the "M"-type mDCzPF as the host represented a 10-fold operational lifetime improvement over the OLED using a "V"-type pDCzPF linked by para-substituted phenyl groups as the host because of the good charge transport ability of the mDCzPF. Additionally, the "M"-type mDCzPF host was also compatible with a blue emitting phosphorescent emitter PtNON. The PtNON-doped OLED using mDCzPF as the host exhibited a peak EQE of 18.3% with a small roll off, yet maintained an EQE of 13.3% at a high brightness of 5000 cd/m2. Thus, the novel "M"-type mDCzPF could be employed as stable host material for efficient OLED emitting across the whole visible spectrum. This study should provide a viable method for designing new host materials for the development of stable and efficient phosphorescent OLEDs.
关键词： operational lifetime,host material,blue device,OLED,high triplet energy
更新于2025-09-16 10:30:52