Ahmad Razi, Zdražil Lukáš, Kalytchuk Sergii, Naldoni Alberto, Rogach Andrey L, Schmuki Patrik, Zboril Radek, Kment Štěpán
Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University Olomouc, Šlechtitelu 27, 783 71 Olomouc, Czech Republic.
Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic.
ACS Appl Mater Interfaces. 2021 Oct 13;13(40):47845-47859. doi: 10.1021/acsami.1c10782. Epub 2021 Sep 28.
Doping and compositional tuning of CsAInCl (A = Ag, Na) double perovskite nanocrystals (PNCs) is considered a promising strategy toward the development of light-emitting sources for applications in solution-processed optoelectronic devices. Oleic acid and oleylamine are by far the most often used surface capping ligands for PNCs. However, the undesirable desorption of these ligands due to proton-exchange reaction during isolation and purification processing results in colloidal and structural instabilities. Thus, the improvement of colloidal and optical stability of PNCs represents one of the greatest challenges in the field. Here, we report a trioctylphosphine-mediated synthesis and purification method toward Sb-alloyed CsNaInCl PNCs with excellent stability and optical features. Nuclear magnetic resonance spectroscopy enabled one to explain the role of trioctylphosphine and to reveal the reaction mechanism during crystal nucleation and growth. Under the optimized reaction conditions, -generated trioctylphosphonium chloride and benzoyl trioctylphosphonium chloride serve as highly reactive halide sources, while benzoyl trioctylphosphonium and oleylammonium cations together with the oleate anion serve as surface capping ligands, which are bound strongly to the PNC surface. The tightly bound ionic pair of oleylammonium oleate and benzoyl trioctylphosphonium chloride/oleate ligands allows one to obtain monodispersed bright-blue-emitting PNCs with high photoluminescence quantum yields exceeding 50% at an optimum Sb content (0.5%), which also exhibit long-term colloidal stability. The approach based on dual cationic ligand passivation of double PNCs opens the doors for applications in other systems with a potential to achieve higher stability along with superior optical properties.
对CsAInCl（A = Ag，Na）双钙钛矿纳米晶体（PNCs）进行掺杂和成分调控被认为是开发用于溶液处理光电器件的发光源的一种有前景的策略。油酸和油胺是目前用于PNCs的最常用的表面封端配体。然而，在分离和纯化过程中，由于质子交换反应，这些配体的不良解吸会导致胶体和结构不稳定性。因此，提高PNCs的胶体和光学稳定性是该领域最大的挑战之一。在此，我们报道了一种三辛基膦介导的合成和纯化方法，用于制备具有优异稳定性和光学特性的Sb合金化CsNaInCl PNCs。核磁共振光谱能够解释三辛基膦的作用，并揭示晶体成核和生长过程中的反应机理。在优化的反应条件下，生成的三辛基氯化铵和苯甲酰三辛基氯化铵作为高活性卤化物源，而苯甲酰三辛基膦和油胺阳离子与油酸根阴离子一起作为表面封端配体，它们与PNC表面紧密结合。油酸油胺和苯甲酰三辛基氯化铵/油酸配体的紧密结合离子对使得在最佳Sb含量（0.5%）下能够获得具有高光致发光量子产率超过50%的单分散亮蓝色发光PNCs，其还表现出长期的胶体稳定性。基于双阳离子配体钝化双PNCs的方法为其他系统的应用打开了大门，这些系统有可能实现更高的稳定性以及优异的光学性能。
