Gahlot Kushagra, de Graaf Sytze, Duim Herman, Nedelcu Georgian, Koushki Razieh M, Ahmadi Majid, Gavhane Dnyaneshwar, Lasorsa Alessia, De Luca Oreste, Rudolf Petra, van der Wel Patrick C A, Loi Maria A, Kooi Bart J, Portale Giuseppe, Calbo Joaquín, Protesescu Loredana
Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747AG, The Netherlands.
Institute of Molecular Science, Universitat de València, c/Catedrático José Beltrán, 2, Paterna, 46980, Spain.
Adv Mater. 2022 Jul;34(30):e2201353. doi: 10.1002/adma.202201353. Epub 2022 Jun 16.
Lead halide perovskite nanocrystals are highly attractive for next-generation optoelectronics because they are easy to synthesize and offer great compositional and morphological tunability. However, the replacement of lead by tin for sustainability reasons is hampered by the unstable nature of Sn oxidation state and by an insufficient understanding of the chemical processes involved in the synthesis. Here, an optimized synthetic route is demonstrated to obtain stable, tunable, and monodisperse CsSnI nanocrystals, exhibiting well-defined excitonic peaks. Similar to lead halide perovskites, these nanocrystals are prepared by combining a precursor mixture of SnI , oleylamine, and oleic acid, with a Cs-oleate precursor. Among the products, nanocrystals with 10 nm lateral size in the γ-orthorhombic phase prove to be the most stable. To achieve such stability, an excess of precursor SnI as well as substoichiometric Sn:ligand ratios are key. Structural, compositional, and optical investigations complemented by first-principle density functional theory calculations confirm that nanocrystal nucleation and growth follow the formation of (R-NH ) SnI nanosheets, with R = C H . Under specific synthetic conditions, stable mixtures of 3D nanocrystals CsSnI and 2D nanosheets (Ruddlesden-Popper (R-NH ) Cs Sn I with n > 1) are obtained. These results set a path to exploiting the high potential of Sn halide perovskite nanocrystals for opto-electronic applications.
卤化铅钙钛矿纳米晶体对下一代光电子学极具吸引力，因为它们易于合成，且在成分和形态上具有很大的可调性。然而，出于可持续发展的原因，用锡取代铅受到锡氧化态不稳定以及对合成过程中涉及的化学过程了解不足的阻碍。在此，展示了一种优化的合成路线，以获得稳定、可调且单分散的CsSnI纳米晶体，其具有明确的激子峰。与卤化铅钙钛矿类似，这些纳米晶体是通过将SnI、油胺和油酸的前驱体混合物与油酸铯前驱体混合制备的。在产物中，γ-正交相横向尺寸为10 nm的纳米晶体被证明是最稳定的。为实现这种稳定性，过量的前驱体SnI以及亚化学计量的Sn:配体比是关键。通过第一性原理密度泛函理论计算补充的结构、成分和光学研究证实，纳米晶体的成核和生长遵循(R-NH ) SnI纳米片的形成，其中R = C H 。在特定的合成条件下，可获得3D纳米晶体CsSnI和2D纳米片（n > 1的Ruddlesden-Popper (R-NH ) Cs Sn I ）的稳定混合物。这些结果为利用卤化锡钙钛矿纳米晶体在光电子应用中的巨大潜力开辟了道路。
