Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
J Phys Chem Lett. 2023 Jun 29;14(25):5940-5948. doi: 10.1021/acs.jpclett.3c01093. Epub 2023 Jun 22.
Controlling the reabsorption of light by an emitting material is one of the keys to improving the performance of light-emitting devices. We prepare a set of size-dependent Cs(Mn/Pb)Cl alloy nanoplatelets (NPls) with substantial enhancement in the exciton Stokes shift, reducing the light-reabsorption significantly. We perform interfacial Mn-alloying using a shuttling ligand that transports MnCl from aqueous to nonaqueous phase and delivers it to NPls. While the exciton Stokes shift in 2-5 monolayer (ML) CsPbBr NPls rises from 20 to 108 meV, the exciton Stokes shift increases drastically up to 600 meV in 2 ML Cs(Mn/Pb)Cl NPls and further reduces upon increasing the thickness. Moreover, the exciton PL peak in the Mn-alloy NPls remains unperturbed by the quantum-confinement effect. A model based on the interplay between Mn/Mn during the charge transfer process is proposed, accounting for such a large exciton Stokes shift. Finally, we utilize the large exciton Stokes-shifted alloy NPls for successful demonstration of white-light generation.
控制发光材料的光再吸收是提高发光器件性能的关键之一。我们制备了一组尺寸相关的 Cs（Mn/Pb）Cl 合金纳米板（NPls），其激子斯托克斯位移显著增强，大大减少了光再吸收。我们使用穿梭配体进行界面 Mn 合金化，该配体将 MnCl 从水相传输到非水相，并将其输送到 NPls。虽然 2-5 单层（ML）CsPbBr NPls 的激子斯托克斯位移从 20 增加到 108 meV，但在 2 ML Cs（Mn/Pb）Cl NPls 中激子斯托克斯位移急剧增加到 600 meV，并且随着厚度的增加进一步减少。此外，Mn 合金 NPls 中的激子 PL 峰不受量子限制效应的影响。提出了一种基于电荷转移过程中 Mn/Mn 相互作用的模型，解释了如此大的激子斯托克斯位移。最后，我们利用具有大激子斯托克斯位移的合金 NPls 成功地演示了白光产生。
