Low amplified spontaneous emission threshold and suppression of electroluminescence efficiency roll-off in layers doped with ter(9,9′-spirobifluorene)
Low amplified spontaneous emission threshold and suppression of electroluminescence efficiency roll-off in layers doped with ter(9,9′-spirobifluorene)
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DOI：
10.1063/1.4945596
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发表时间：
2016-03-28
影响因子：
4
通讯作者：
Adachi, Chihaya
中科院分区：
文献类型：
--
作者：
Inoue, Munetomo;Matsushima, Toshinori;Adachi, Chihaya
我们证明了在4，4 ′-双（咔唑-9-基）联苯（CBP）基质层中掺杂的三（9，9 ′-螺二芴）（TSBF）显示出低的放大自发辐射（ASE）阈值（E-th = 1.0 μ J cm（-2））和在高电流密度下抑制的电致发光效率滚降（直到100mAcm（-2）没有滚降）。低ASE阈值的一个起源是TSBF掺杂的CBP层具有非常大的辐射衰减常数（k（r）= 1.1 × 10（9）s（-1））。单重态-三重态湮灭在TSBF掺杂的CBP层中几乎被抑制，这可以归因于TSBF的发射和三重态吸收之间的小重叠。此外，TSBF和CBP之间的小能级差最大限度地减少了TSBF中的载流子陷阱，从而抑制了单态极化子湮灭。TSBF在本研究中所研究的有机激光染料中表现出最低的Eth和最受抑制的效率滚降之一，因此，被认为是未来实现电泵浦有机半导体激光二极管的有希望的候选者。(C)2016 AIP Publishing LLC.
We demonstrate that ter(9,9'-spirobifluorene) (TSBF) doped in a host matrix layer of 4,4'-bis (carbazol-9-yl) biphenyl (CBP) shows a low amplified spontaneous emission (ASE) threshold (E-th = 1.0 mu J cm(-2)) and suppressed electroluminescence efficiency roll-off at high current densities (no roll-off up to 100mAcm(-2)). One origin of the low ASE threshold is that the TSBF-doped CBP layer possesses a very large radiative decay constant (k(r) = 1.1 x 10(9) s(-1)). Singlet-triplet annihilation is almost suppressed in the TSBF-doped CBP layer, which can be ascribed to the small overlap between the emission and triplet absorption of TSBF. Also, the small energy level difference between TSBF and CBP minimizes carrier trapping in TSBF, leading to the suppression of singlet-polaron annihilation. TSBF showed one of the lowest Eth and the most suppressed efficiency rolloff among organic laser dyes investigated in this study and, therefore, is believed to be a promising candidate to realize electrically pumped organic semiconductor laser diodes in the future. (C) 2016 AIP Publishing LLC.