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Inverse size-dependent Stokes shift in strongly quantum confined CsPbBr3 perovskite nanoplates
Nanoscale ( IF 5.8 ) Pub Date : 2022-11-15 , DOI: 10.1039/d2nr03275a
Amit Vurgaft 1 , Rotem Strassberg 1 , Reut Shechter 2 , Rachel Lifer 2 , Jakob C Dahl 3, 4 , Emory M Chan 4 , Yehonadav Bekenstein 1, 2
Affiliation  

Colloidal semiconductor nanocrystals (NCs) are used as bright chromatic fluorophores for energy-efficient displays. We focus here on the size-dependent Stokes shift for CsPbBr3 nanocrystals. The Stokes shift, i.e., the difference between the wavelengths of absorption and emission maxima, is crucial for display application, as it controls the degree to which light is reabsorbed by the emitting material reducing the energetic efficiency. One major impediment to the industrial adoption of NCs is that slight deviations in manufacturing conditions may result in a wide dispersion of the product's properties. A data-driven analysis of over 2000 reactions comparing two data sets, one produced via standard colloidal synthesis and the other via high-throughput automated synthesis is discussed. We show that differences in the reaction conditions of colloidal CsPbBr3 nanocrystals yield nanocrystals with opposite Stokes shift size-dependent trends. These match the morphologies of two-dimensional nanoplatelets (NPLs) and nanocrystal cubes. The Stokes shift size dependence trend of NPLs and nanocubes is non-monotonic indicating different physics is at play for the two nanocrystal morphologies. For nanocrystals with cubic shape, with the increase of edge length, there is a significant decrease in Stokes shift values. However, for NPLs with the increase of thickness (1–4 ML), Stokes shift values will increase. The study emphasizes the transition from a spectroscopic point of view and relates the two Stokes shift trends to 2D and 0D exciton dimensionalities for the two morphologies. Our findings highlight the importance of CsPbBr3 nanocrystal morphology for Stokes shift prediction.

中文翻译:

强量子限制的 CsPbBr3 钙钛矿纳米板中的反尺寸依赖 Stokes 位移

胶体半导体纳米晶体 (NC) 用作节能显示器的明亮彩色荧光团。我们在此重点关注 CsPbBr 3纳米晶体的尺寸依赖性斯托克斯位移。斯托克斯位移,吸收波长和发射最大值之间的差异,对于显示应用至关重要,因为它控制光被发射材料重新吸收的程度,从而降低能量效率。在工业上采用 NC 的一个主要障碍是制造条件的轻微偏差可能导致产品性能的广泛差异。对 2000 多个反应进行数据驱动分析,比较两组数据,一组通过标准胶体合成产生,另一组通过讨论了高通量自动化合成。我们表明胶体 CsPbBr 3反应条件的差异纳米晶体产生具有相反斯托克斯位移尺寸依赖趋势的纳米晶体。这些与二维纳米片 (NPL) 和纳米晶体立方体的形态相匹配。NPL 和纳米立方体的 Stokes 位移尺寸依赖趋势是非单调的,表明两种纳米晶体形态存在不同的物理现象。对于立方体形状的纳米晶,随着边长的增加,斯托克斯位移值显着降低。然而,对于厚度增加 (1–4 ML) 的 NPL,斯托克斯位移值会增加。该研究强调了从光谱角度的转变,并将两种斯托克斯位移趋势与两种形态的 2D 和 0D 激子维度相关联。我们的发现强调了 CsPbBr 3的重要性用于斯托克斯位移预测的纳米晶体形态。
更新日期:2022-11-15
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