Recycling of Triplets into Singlets for High-Performance Organic Lasers
Recycling of Triplets into Singlets for High-Performance Organic Lasers
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DOI：
10.1002/adom.202101302
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发表时间：
2021-10-23
影响因子：
9
通讯作者：
Adachi, Chihaya
中科院分区：
文献类型：
--
作者：
Senevirathne, Chathuranganie A. M.;Yoshida, Seiya;Adachi, Chihaya
在有机半导体中实现连续波（CW）激光是一项艰巨的任务，因为长寿命的三重态通过单重态-三重态湮灭（STA）淬灭辐射单重态。为了避免STA并在CW或长脉冲光激发下操作有机激光器，需要从有机激光增益介质中去除三重态。然而，这种三重态去除导致激子的损失。除了去除有害的三重态之外，这里还报道了三重态再循环过程，其包括三重态清除和经由三重态-三重态湮灭（TTA）的连续三重态上转换以在激光介质中再生发射性单重态激子。9-（1-萘基）-10-（4-（2-萘基）苯基）蒽的蒽衍生物（NaNaP-A）和4，4 '-双[4-（二苯基氨基）苯乙烯基]联苯的激光染料（BDAVBi）分别用作三重态再循环敏化剂和发射激光染料。在该激光系统中，NaNaP-A可以有效地将在BDAVBi上形成的三重态重激发，因为NaNaP-A的三重态能级比BDAVBi的更深，然后NaNaP-A通过TTA将三重态重激发成BDAVBi的单重态。TTA补偿和克服了该激光系统中的STA。因此，这些激光器件可以操作的长脉冲宽度高达10毫秒。这种独特的三重态回收行为证实了瞬态光致发光（PL）和电致发光（EL）的研究。
Achieving continuous-wave (CW) lasing in organic semiconductors is known to be a difficult task because long-lived triplets quench radiative singlets via singlet-triplet annihilation (STA). To avoid STA and operate organic lasers in CW or long-pulse photoexcitation, the triplets need to be removed from an organic laser gain medium. However, this triplet removal leads to a loss of excitons. In addition to removing the detrimental triplets, here it is reported a triplet recycling process, which includes triplet scavenging and successive triplet upconversion via triplet-triplet annihilation (TTA) to regenerate emissive singlet excitons in a laser medium. An anthracene derivative of 9-(1-naphthalenyl)-10-(4-(2-naphthalenyl)phenyl)anthracene (NaNaP-A) and a laser dye of 4,4 '-bis[4-(diphenylamino)styryl]biphenyl (BDAVBi) are used as the triplet recycling sensitizer and the emitting laser dye, respectively. In this laser system, NaNaP-A can efficiently scavenge the triplets formed on BDAVBi because the triplet level is deeper for NaNaP-A than for BDAVBi, and then NaNaP-A successively recycles the triplets into the BDAVBi's singlet state via TTA. The TTA compensates and overcomes the STA in this laser system. Hence, these laser devices can be operated with long pulse widths of up to 10 ms. This unique triplet recycling behavior is confirmed by transient photoluminescence (PL) and electroluminescence (EL) studies.