Shamraienko Volodymyr, Haidei Valeriia, Antanovich Artsiom, Hübner René, Erwin Steven C, Lesnyak Vladimir, Eychmüller Alexander
Physical Chemistry, TU Dresden, Zellescher Weg 19, 01069 Dresden, Germany.
Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstraße 3A, 30167 Hannover, Germany.
Chem Mater. 2025 Aug 7;37(16):6151-6160. doi: 10.1021/acs.chemmater.5c00650. eCollection 2025 Aug 26.
The growth of atomically flat CdSe nanoplatelets (NPLs) thicker than 5 monolayers (ML) remains a major challenge in colloidal semiconductor synthesis, particularly for core/crown heterostructures. Here we report the successful synthesis of zinc-blende CdSe NPLs with unprecedented thicknesses of 6 and 7 ML, exhibiting sharp photoluminescence at 579 and 596 nm, respectively. We demonstrate that these thick NPLs can serve as cores for CdSe/CdS core/crown heterostructures, confirmed by lateral size expansion and the emergence of characteristic CdS absorption features. Through density-functional theory calculations, we uncover a critical relationship between NPL shape and crown growth: fluoride species bind three times stronger to {100} facets of rectangular NPLs compared to {110} facets of square NPLs, effectively poisoning crown growth on rectangular species. This mechanistic insight explains the shape-dependent success of crown formation and provides a framework for controlling two-dimensional (2D) semiconductor growth. Our optimized synthesis of thick core NPLs and their crown-enhanced derivatives significantly expands the spectral range of CdSe-based NPLs, advancing their development as narrow-line width red emitters.
对于厚度超过5个单层（ML）的原子级平整的CdSe纳米片（NPL）的生长，在胶体半导体合成中仍然是一个重大挑战，特别是对于核/壳异质结构而言。在此，我们报告了成功合成具有6 ML和7 ML前所未有的厚度的闪锌矿型CdSe NPL，分别在579 nm和596 nm处表现出尖锐的光致发光。我们证明这些厚的NPL可以作为CdSe/CdS核/壳异质结构的核，这通过横向尺寸扩展和特征性的CdS吸收特征的出现得到证实。通过密度泛函理论计算，我们揭示了NPL形状与壳生长之间的关键关系：氟化物物种与矩形NPL的{100}面的结合强度是与方形NPL的{110}面结合强度的三倍，有效地抑制了矩形物种上的壳生长。这种机理见解解释了壳形成在形状上的成功，并为控制二维（2D）半导体生长提供了一个框架。我们对厚核NPL及其壳增强衍生物的优化合成显著扩展了基于CdSe的NPL的光谱范围，推动了它们作为窄线宽红色发射体的发展。
