Temperature dependence of photoluminescence properties in a thermally activated delayed fluorescence emitter
Temperature dependence of photoluminescence properties in a thermally activated delayed fluorescence emitter
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DOI：
10.1063/1.4878397
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发表时间：
2014-05
影响因子：
4
通讯作者：
Akitsugu Niwa;Takashi Kobayashi;T. Nagase;K. Goushi;C. Adachi;H. Naito
中科院分区：
文献类型：
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作者：
Akitsugu Niwa;Takashi Kobayashi;T. Nagase;K. Goushi;C. Adachi;H. Naito
利用稳态和时间分辨光致发光（PL）光谱，我们研究了1,2,3,5 - 四（咔唑 - 9 - 基）- 4,6 - 二氰基苯（4CzIPN）的光致发光特性的温度依赖性，其单重态和三重态激发态之间的能隙较小，因此表现出高效的热激活延迟荧光[H. 宇山等人，《自然》492，235（2012）]。在约100 K以下，4CzIPN薄膜的光致发光量子效率被大幅抑制，并出现强烈的光激发强度依赖性。考虑到三重态 - 三重态湮灭过程，通过使用单重态和三重态激发态密度的速率方程可以解释这些特性。
Using steady-state and time-resolved photoluminescence (PL) spectroscopy, we have investigated the temperature dependence of PL properties of 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyano-benzene (4CzIPN), which have a small energy gap between its singlet and triplet excited states and thus exhibits efficient thermally activated delayed fluorescence [H. Uoyama et al., Nature 492, 235 (2012)]. Below around 100 K, PL quantum efficiency of 4CzIPN thin films is largely suppressed and strong photoexcitation intensity dependence appears. These features can be explained by using rate equations for the densities of singlet and triplet excited states considering a triplet-triplet annihilation process.