Zhu Chenglian, Marczak Malwina, Feld Leon, Boehme Simon C, Bernasconi Caterina, Moskalenko Anastasiia, Cherniukh Ihor, Dirin Dmitry, Bodnarchuk Maryna I, Kovalenko Maksym V, Rainò Gabriele
Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland.
Laboratory for Thin Films and Photovoltaics, Empa - Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland.
Nano Lett. 2022 May 11;22(9):3751-3760. doi: 10.1021/acs.nanolett.2c00756. Epub 2022 Apr 25.
Attaining pure single-photon emission is key for many quantum technologies, from optical quantum computing to quantum key distribution and quantum imaging. The past 20 years have seen the development of several solid-state quantum emitters, but most of them require highly sophisticated techniques (e.g., ultrahigh vacuum growth methods and cryostats for low-temperature operation). The system complexity may be significantly reduced by employing quantum emitters capable of working at room temperature. Here, we present a systematic study across ∼170 photostable single CsPbX (X: Br and I) colloidal quantum dots (QDs) of different sizes and compositions, unveiling that increasing quantum confinement is an effective strategy for maximizing single-photon purity due to the suppressed biexciton quantum yield. Leveraging the latter, we achieve 98% single-photon purity ((0) as low as 2%) from a cavity-free, nonresonantly excited single 6.6 nm CsPbI QDs, showcasing the great potential of CsPbX QDs as room-temperature highly pure single-photon sources for quantum technologies.
实现纯单光子发射是许多量子技术的关键，从光量子计算到量子密钥分发和量子成像。在过去的20年里，已经开发出了几种固态量子发射器，但其中大多数都需要高度复杂的技术（例如，超高真空生长方法和用于低温操作的低温恒温器）。通过使用能够在室温下工作的量子发射器，可以显著降低系统复杂性。在这里，我们对约170个不同尺寸和组成的光稳定单CsPbX（X：Br和I）胶体量子点（QDs）进行了系统研究，发现由于双激子量子产率的抑制，增加量子限制是最大化单光子纯度的有效策略。利用后者，我们从一个无腔、非共振激发的单个6.6 nm CsPbI量子点中实现了98%的单光子纯度（(0)低至2%），展示了CsPbX量子点作为用于量子技术的室温高纯单光子源的巨大潜力。
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