The low cost, ease of preparation, colour tunability and wide application range garnered huge research interest on organic light emitting diode materials (OLED). The development of white light-emitting organic diode materials is mostly targeted for this. Anthracene derivatives have recently emerged as low-cost and efficient blue light-emitting diodes. However, developing efficient organic diode materials that cover the entire visible spectrum is very challenging. Herein, we demonstrated that Nile red (NR)-doped 9,10-diphenylanthracene (DPA) nanoaggregates provided strong white light emission upon excitation with near UV light. The dual emissions of the DPA nanoaggregates covering the blue and green regions were exploited and combined with the controlled red emission of the properly doped NR dye to cover the full visible spectrum, rendering white light emission with a quantum yield of >0.4. The fluorescence spectra of the DPA nanoaggregates doped with NR at various concentrations were monitored and their CIE coordinates were followed to evaluate the proper doping ratio for equal-energy white-light emission. Concurrent time-resolved emission studies provided mechanistic insights into the energy transfer from the exciton and excimer states of DPA to NR. It was revealed that the energy transfer from the singlet excitonic state of DPA followed the diffusion-assisted resonance energy transfer (RET) model. On the other hand, the excimer state showed negligible diffusion and energy transfer from this state found to follow the single-step Förster resonance energy transfer mechanism. The observation of efficient white light emission in the doped DPA nanoaggregates was proposed to have prospective applications in OLED devices, given the fact that triplet excitons may be exploited for emission through the efficient triplet–triplet annihilation contribution to fluorescence enhancement.

中文翻译：

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尼罗红掺杂的9,10-二苯基蒽纳米聚集体在近紫外光激发下的能量转移介导的白光发射†

低成本，易于制备，颜色可调性和广泛的应用范围引起了对有机发光二极管材料（OLED）的巨大研究兴趣。为此，主要目标是发白光的有机二极管材料的开发。蒽衍生物最近已作为低成本和高效的蓝色发光二极管出现。但是，开发覆盖整个可见光谱的高效有机二极管材料非常具有挑战性。在本文中，我们证明了掺有尼罗红（NR）的9,10-二苯基蒽（DPA）纳米聚集体在用近紫外光激发后提供强白光发射。利用了覆盖蓝色和绿色区域的DPA纳米聚集体的双重发射，并与适当掺杂的NR染料的受控红色发射相结合，以覆盖整个可见光谱，产生白光发射，量子产率> 0.4。监测了掺杂有不同浓度NR的DPA纳米聚集体的荧光光谱，并跟踪了它们的CIE坐标，以评估等能量白光发射的适当掺杂比。同时进行的时间分辨排放研究为从DPA的激子和准分子状态到NR的能量转移提供了机械的见解。结果表明，DPA的单重态激子态的能量转移遵循扩散辅助共振能量转移（RET）模型。另一方面，准分子状态显示出可忽略的扩散和从该状态的能量转移，发现遵循单步福斯特共振能量转移机制。