Li Pengji, Biesterfeld Leon, Klepzig Lars F, Yang Jingzhong, Ngo Huu Thoai, Addad Ahmed, Rakow Tom N, Guan Ruolin, Rugeramigabo Eddy P, Zaluzhnyy Ivan, Schreiber Frank, Biadala Louis, Lauth Jannika, Zopf Michael
Institute of Solid State Physics, Leibniz University Hannover, Appelstraße 2, D-30167 Hannover, Germany.
Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering - Innovation Across Disciplines), Welfengarten 1A, D-30167 Hannover, Germany.
Nano Lett. 2024 Dec 25;24(51):16293-16300. doi: 10.1021/acs.nanolett.4c04402. Epub 2024 Nov 22.
Colloidal semiconductor nanocrystals are promising materials for classical and quantum light sources due to their efficient photoluminescence (PL) and versatile chemistry. While visible emitters are well-established, excellent (near-infrared) sources are still being pursued. We present the first comprehensive analysis of low-temperature PL from two-dimensional (2D) PbS nanoplatelets (NPLs). Ultrathin 2D PbS NPLs exhibit high crystallinity confirmed by scanning transmission electron microscopy, revealing Moiré patterns in overlapping NPLs. At 4 K, unique PL features are observed in single PbS NPLs, including narrow zero-phonon lines with line widths down to 0.6 meV and a linear degree of polarization up to 90%. Time-resolved measurements identify trions as the dominant emission source with a 2.3 ns decay time. Sub-meV spectral diffusion and no inherent blinking over minutes are observed, as well as discrete spectral jumps without memory effects. These findings advance the understanding and underscore the potential of colloidal PbS NPLs for optical and quantum technologies.
由于具有高效的光致发光（PL）特性和多样的化学性质，胶体半导体纳米晶体是用于经典和量子光源的很有前景的材料。虽然可见发光体已经很成熟，但仍在寻求优异的（近红外）光源。我们首次对二维（2D）硫化铅纳米片（NPLs）的低温光致发光进行了全面分析。超薄二维硫化铅纳米片表现出高结晶度，扫描透射电子显微镜证实了这一点，并揭示了重叠纳米片中的莫尔条纹。在4K时，在单个硫化铅纳米片中观察到独特的光致发光特性，包括线宽低至0.6meV的窄零声子线和高达90%的线性偏振度。时间分辨测量确定三重态激子为主要发射源，衰减时间为2.3ns。观察到亚毫电子伏特光谱扩散，且在数分钟内无固有闪烁，以及无记忆效应的离散光谱跳跃。这些发现增进了对胶体硫化铅纳米片的理解，并突出了其在光学和量子技术方面的潜力。
