Boosting Tunable Blue Luminescence of Halide Perovskite Nanoplatelets through Postsynthetic Surface Trap Repair,Nano Letters

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Boosting Tunable Blue Luminescence of Halide Perovskite Nanoplatelets through Postsynthetic Surface Trap Repair
Nano Letters ( IF 9.6 ) Pub Date : 2018-07-10 00:00:00 , DOI: 10.1021/acs.nanolett.8b02190
Bernhard J. Bohn _{1,

2} , Yu Tong _{1,

2} , Moritz Gramlich _{1,

2} , May Ling Lai ₃ , Markus Döblinger ₄ , Kun Wang ₅ , Robert L. Z. Hoye ₃ , Peter Müller-Buschbaum ₅ , Samuel D. Stranks ₃ , Alexander S. Urban _{1,

2} , Lakshminarayana Polavarapu _{1,

2} , Jochen Feldmann _{1,

2}

Affiliation

The easily tunable emission of halide perovskite nanocrystals throughout the visible spectrum makes them an extremely promising material for light-emitting applications. Whereas high quantum yields and long-term colloidal stability have already been achieved for nanocrystals emitting in the red and green spectral range, the blue region currently lags behind with low quantum yields, broad emission profiles, and insufficient colloidal stability. In this work, we present a facile synthetic approach for obtaining two-dimensional CsPbBr₃ nanoplatelets with monolayer-precise control over their thickness, resulting in sharp photoluminescence and electroluminescence peaks with a tunable emission wavelength between 432 and 497 nm due to quantum confinement. Subsequent addition of a PbBr₂-ligand solution repairs surface defects likely stemming from bromide and lead vacancies in a subensemble of weakly emissive nanoplatelets. The overall photoluminescence quantum yield of the blue-emissive colloidal dispersions is consequently enhanced up to a value of 73 ± 2%. Transient optical spectroscopy measurements focusing on the excitonic resonances further confirm the proposed repair process. Additionally, the high stability of these nanoplatelets in films and to prolonged ultraviolet light exposure is shown.

中文翻译：

通过合成后表面陷阱修复促进卤化物钙钛矿纳米片的可调蓝色发光。

卤化钙钛矿纳米晶体在整个可见光谱范围内的发射光谱很容易调整，使它们成为发光应用中极有希望的材料。对于在红色和绿色光谱范围内发射的纳米晶体，已经实现了高量子产率和长期的胶体稳定性，而蓝色区域目前滞后于低量子产率，宽发射谱和胶体稳定性不足。在这项工作中，我们提出了一种简便的合成方法，以获得具有单层精确控制其厚度的二维CsPbBr ₃纳米血小板，由于量子限制，产生了可调节的发射波长在432至497 nm之间的尖锐的光致发光和电致发光峰。随后添加PbBr ₂-配体溶液修复了可能由溴化物和铅空位引起的表面缺陷，这些表面缺陷是由大量微弱发射的纳米血小板组成的。因此，蓝色发射胶体分散体的总光致发光量子产率提高到73±2％的值。聚焦于激子共振的瞬态光谱测量进一步证实了所提出的修复过程。另外，显示了这些纳米片在膜中的高稳定性以及对延长的紫外线暴露的高稳定性。

更新日期：2018-07-10

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