Yu Junhong, Sharma Manoj, Sharma Ashma, Delikanli Savas, Volkan Demir Hilmi, Dang Cuong
1LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, The Photonics Institute (TPI), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore.
2Department of Electrical and Electronics Engineering and Department of Physics, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara Turkey.
Light Sci Appl. 2020 Feb 27;9:27. doi: 10.1038/s41377-020-0262-7. eCollection 2020.
Excitonics, an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore's law. Currently, the development of excitonic devices, where exciton flow is controlled, is mainly focused on electric-field modulation or exciton polaritons in high-Q cavities. Here, we show an all-optical strategy to manipulate the exciton flow in a binary colloidal quantum well complex through mediation of the Förster resonance energy transfer (FRET) by stimulated emission. In the spontaneous emission regime, FRET naturally occurs between a donor and an acceptor. In contrast, upon stronger excitation, the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors. Specifically, the acceptors' stimulated emission significantly accelerates the exciton flow, while the donors' stimulated emission almost stops this process. On this basis, a FRET-coupled rate equation model is derived to understand the controllable exciton flow using the density of the excited donors and the unexcited acceptors. The results will provide an effective all-optical route for realizing excitonic devices under room temperature operation.
由于半导体电子学正迅速接近摩尔定律的极限，激子学作为一种有前景的信息处理替代方案应运而生。目前，激子器件的发展主要集中在电场调制或高Q腔中的激子极化激元，其中激子流受到控制。在此，我们展示了一种全光策略，通过受激发射介导的Förster共振能量转移（FRET）来操纵二元胶体量子阱复合物中的激子流。在自发发射状态下，FRET自然地发生在供体和受体之间。相比之下，在更强的激发下，受激发射对激子的超快消耗有效地控制了激子从供体到受体的流动。具体而言，受体的受激发射显著加速了激子流，而供体的受激发射几乎停止了这一过程。在此基础上，推导了一个FRET耦合速率方程模型，以利用激发供体和未激发受体的密度来理解可控的激子流。这些结果将为在室温操作下实现激子器件提供一条有效的全光途径。
