日立国立材料研究所Hong-Tao Sun团队报道了高发光胶体铯锡卤化物钙钛矿纳米晶的理论指导合成。相关研究成果发表于2021年4月1日出版的《美国化学会杂志》。

高发光胶体CsSnX3（X=卤素）钙钛矿型纳米晶体（NCs）的合成一直是一个难题，因为人们对如何合理地抑制结构缺陷的形成缺乏基本的了解，而这些缺陷对辐射载流子复合过程有着重要的影响。

该文中，研究人员开发了一个高发光CsSnX3 NCs一般合成概念的理论指导。在密度泛函理论计算和分子动力学模拟的指导下，研究人员预测，尽管各种缺陷的化学势相关形成能有相反的趋势，但通过降低tin空位的密度，可以获得窄发射的高发光CsSnI3 NCs。然后，研究人员开发了一种允许在大范围内合理微调反应物比例的胶体合成策略，但仍然会导致CsSnI3 NCs的形成。

通过合理地采用富锡反应条件，研究人员获得了破记录的发射量子产率为18.4%的窄带发射CsSnI3 NCs，比文献报道的高出50多倍。系统的表面态表征表明，这些NCs具有贫Cs/I的表面，并被低密度的有机配体所覆盖，使其成为无需任何后合成配体管理的光电器件的理想候选材料。通过进一步展示高发光CsSnI2.5Br0.5和CsSnI2.25Br0.75ncs的合成表明该合成概念的普适性。

研究结果不仅突出了计算在高质量胶体钙钛矿纳米晶合成中的指导价值，而且可以促进对锡基钙钛矿纳米晶的研究，加速其在一系列高性能光电器件中的潜在应用。

附：英文原文

Title: Theory-Guided Synthesis of Highly Luminescent Colloidal Cesium Tin Halide Perovskite Nanocrystals

Author: Qi Liu, Jun Yin, Bin-Bin Zhang, Jia-Kai Chen, Yang Zhou, Lu-Min Zhang, Lu-Ming Wang, Qing Zhao, Jingshan Hou, Jie Shu, Bo Song, Naoto Shirahata, Osman M. Bakr, Omar F. Mohammed, Hong-Tao Sun

Issue&Volume: April 1, 2021

Abstract: The synthesis of highly luminescent colloidal CsSnX3 (X = halogen) perovskite nanocrystals (NCs) remains a long-standing challenge due to the lack of a fundamental understanding of how to rationally suppress the formation of structural defects that significantly influence the radiative carrier recombination processes. Here, we develop a theory-guided, general synthetic concept for highly luminescent CsSnX3 NCs. Guided by density functional theory calculations and molecular dynamics simulations, we predict that, although there is an opposing trend in the chemical potential-dependent formation energies of various defects, highly luminescent CsSnI3 NCs with narrow emission could be obtained through decreasing the density of tin vacancies. We then develop a colloidal synthesis strategy that allows for rational fine-tuning of the reactant ratio in a wide range but still leads to the formation of CsSnI3 NCs. By judiciously adopting a tin-rich reaction condition, we obtain narrow-band-emissive CsSnI3 NCs with a record emission quantum yield of 18.4%, which is over 50 times larger than those previously reported. Systematic surface-state characterizations reveal that these NCs possess a Cs/I-lean surface and are capped with a low density of organic ligands, making them an excellent candidate for optoelectronic devices without any postsynthesis ligand management. We showcase the generalizability of our concept by further demonstrating the synthesis of highly luminescent CsSnI2.5Br0.5 and CsSnI2.25Br0.75 NCs. Our findings not only highlight the value of computation in guiding the synthesis of high-quality colloidal perovskite NCs but also could stimulate intense efforts on tin-based perovskite NCs and accelerate their potential applications in a range of high-performance optoelectronic devices.

DOI: 10.1021/jacs.1c01049

Source: https://pubs.acs.org/doi/10.1021/jacs.1c01049