Liška Petr, Musálek Tomáš, Šamořil Tomáš, Kratochvíl Matouš, Matula Radovan, Horák Michal, Nedvěd Matěj, Urban Jakub, Planer Jakub, Rovenská Katarína, Dvořák Petr, Kolíbal Miroslav, Křápek Vlastimil, Kalousek Radek, Šikola Tomáš
Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno, Czech Republic.
Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00 Brno, Czech Republic.
J Phys Chem C Nanomater Interfaces. 2023 Jun 20;127(25):12404-12413. doi: 10.1021/acs.jpcc.3c03056. eCollection 2023 Jun 29.
We report on the optical properties of a CsPbBr polycrystalline thin film on a single grain level. A sample composed of isolated nanocrystals (NCs) mimicking the properties of the polycrystalline thin film grains that can be individually probed by photoluminescence spectroscopy was prepared. These NCs were analyzed using correlative microscopy allowing the examination of structural, chemical, and optical properties from identical sites. Our results show that the stoichiometry of the CsPbBr NCs is uniform and independent of the NCs' morphology. The photoluminescence (PL) peak emission wavelength is slightly dependent on the dimensions of NCs, with a blue shift up to 9 nm for the smallest analyzed NCs. The magnitude of the blueshift is smaller than the emission line width, thus detectable only by high-resolution PL mapping. By comparing the emission energies obtained from the experiment and a rigorous effective mass model, we can fully attribute the observed variations to the size-dependent quantum confinement effect.
我们报道了单颗粒水平上CsPbBr多晶薄膜的光学性质。制备了一个由孤立纳米晶体（NCs）组成的样品，该样品模拟了多晶薄膜晶粒的性质，可通过光致发光光谱对其进行单独探测。使用相关显微镜对这些NCs进行分析，从而能够从相同位置检查其结构、化学和光学性质。我们的结果表明，CsPbBr NCs的化学计量是均匀的，且与NCs的形态无关。光致发光（PL）峰值发射波长略微依赖于NCs的尺寸，对于所分析的最小NCs，蓝移可达9 nm。蓝移的幅度小于发射线宽，因此只有通过高分辨率PL映射才能检测到。通过比较实验获得的发射能量和严格的有效质量模型，我们可以将观察到的变化完全归因于尺寸依赖的量子限制效应。
