Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state.
Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state.
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DOI：
10.1126/sciadv.1500889
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发表时间：
2016-01
期刊：
影响因子：
13.6
通讯作者：
Samuel ID
中科院分区：
文献类型：
--
作者：
Bergmann L;Hedley GJ;Baumann T;Bräse S;Samuel ID
在一种表现出热激活延迟荧光的铜配合物中，测量到系间窜越时间为27皮秒。
热激活延迟荧光（TADF）材料中的系间窜越是一个重要过程，它控制着单重态转变为三重态的速率；然而，在TADF材料中直接测量这一过程是困难的。TADF是一项重要的新兴技术，它能够在有机发光二极管中收集三重态以及单重态激发态用于发光。我们观察到了一种固态的高发光中性铜（I）配合物的皮秒时间分辨光致发光，该配合物表现出TADF。系间窜越的时间常数经测量为27皮秒。随后的整体反向系间窜越较慢，导致布居平衡和TADF，其平均寿命为11.5微秒。对这类单核铜（I）配合物在固态下系间窜越的首次测量，使人们更好地理解了确保高效TADF的激发态过程和机制。
An intersystem crossing time of 27 ps is measured in a copper complex that shows thermally activated delayed fluorescence. Intersystem crossing in thermally activated delayed fluorescence (TADF) materials is an important process that controls the rate at which singlet states convert to triplets; however, measuring this directly in TADF materials is difficult. TADF is a significant emerging technology that enables the harvesting of triplets as well as singlet excited states for emission in organic light emitting diodes. We have observed the picosecond time-resolved photoluminescence of a highly luminescent, neutral copper(I) complex in the solid state that shows TADF. The time constant of intersystem crossing is measured to be 27 picoseconds. Subsequent overall reverse intersystem crossing is slow, leading to population equilibration and TADF with an average lifetime of 11.5 microseconds. These first measurements of intersystem crossing in the solid state in this class of mononuclear copper(I) complexes give a better understanding of the excited-state processes and mechanisms that ensure efficient TADF.