Dai Liwei, Lesyuk Rostyslav, Karpulevich Anastasia, Torche Abderrezak, Bester Gabriel, Klinke Christian
Institute of Physical Chemistry , University of Hamburg , Martin-Luther-King-Platz 6 , 20146 Hamburg , Germany.
Pidstryhach Institute for Applied Problems of Mechanics and Mathematics of NAS of Ukraine, Naukowa str. 3b, 79060 Lviv & Department of Photonics , Lviv Polytechnic National University , Bandery str. 12 , 79000 Lviv , Ukraine.
J Phys Chem Lett. 2019 Jul 18;10(14):3828-3835. doi: 10.1021/acs.jpclett.9b01466. Epub 2019 Jun 27.
Ultrathin semiconductor nanocrystals (NCs) with at least one dimension below their exciton Bohr radius receive a rapidly increasing attention due to their unique physicochemical properties. These superior properties highly depend on the shape and crystal phase of semiconductor NCs. Here, we demonstrate not only the synthesis of well-defined ultrathin ZnS nanoplatelets (NPLs) with excitonic absorption and emission, but also the shape/phase transformation between wurtzite (WZ) NPLs and zinc blende (ZB) nanorods (NRs). UV-vis absorption spectra of WZ-ZnS NPLs clearly exhibit a sharp excitonic peak that is not observed in ZB-ZnS NRs. Besides, the photoluminescence characterization shows that WZ-ZnS NPLs have a narrow excitonic emission peak, while ZB-ZnS NRs exhibit a broad collective emission band consisting of four emission peaks. The appearance of excitonic features in the absorption spectra of ZnS NPLs is explained by interband electronic transitions, which is simulated in the framework of atomic effective pseudopotentials (AEP).
至少有一个维度小于其激子玻尔半径的超薄半导体纳米晶体（NCs），因其独特的物理化学性质而受到越来越多的关注。这些优异的性质高度依赖于半导体纳米晶体的形状和晶相。在此，我们不仅展示了具有激子吸收和发射的明确超薄ZnS纳米片（NPLs）的合成，还展示了纤锌矿（WZ）NPLs与闪锌矿（ZB）纳米棒（NRs）之间的形状/相转变。WZ-ZnS NPLs的紫外-可见吸收光谱清楚地显示出一个尖锐的激子峰，而在ZB-ZnS NRs中未观察到。此外，光致发光表征表明，WZ-ZnS NPLs有一个窄的激子发射峰，而ZB-ZnS NRs表现出一个由四个发射峰组成的宽集体发射带。ZnS NPLs吸收光谱中激子特征的出现是由带间电子跃迁解释的，这在原子有效赝势（AEP）框架内进行了模拟。
