Dataset Information

Highly Emissive Divalent-Ion-Doped Colloidal CsPb_1-xM_xBr₃ Perovskite Nanocrystals through Cation Exchange.

ABSTRACT: Colloidal CsPbX₃ (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX₃ NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr₃ NCs, whereby Pb²⁺ is exchanged for several isovalent cations, resulting in doped CsPb_1-xM_xBr₃ NCs (M= Sn²⁺, Cd²⁺, and Zn²⁺; 0 < x ? 0.1), with preservation of the original NC shape. The size of the parent NCs is also preserved in the product NCs, apart from a small (few %) contraction of the unit cells upon incorporation of the guest cations. The partial Pb²⁺ for M²⁺ exchange leads to a blue-shift of the optical spectra, while maintaining the high photoluminescence quantum yields (>50%), sharp absorption features, and narrow emission of the parent CsPbBr₃ NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb²⁺ for M²⁺ cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs.

SUBMITTER: van der Stam W

PROVIDER: S-EPMC5364419 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Highly Emissive Divalent-Ion-Doped Colloidal CsPb1-xMxBr3 Perovskite Nanocrystals through Cation Exchange.

van der Stam Ward W Geuchies Jaco J JJ Altantzis Thomas T van den Bos Karel H W KH Meeldijk Johannes D JD Van Aert Sandra S Bals Sara S Vanmaekelbergh Daniel D de Mello Donega Celso C

Journal of the American Chemical Society 20170310 11

Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3 NCs. Here, we present a method that allow ...[more]

PMID: 28260380

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Project description:Hybrid organic-inorganic and fully inorganic lead halide perovskite nanocrystals (NCs) have recently emerged as versatile solution-processable light-emitting and light-harvesting optoelectronic materials. A particularly difficult challenge lies in warranting the practical utility of such semiconductor NCs in the red and infrared spectral regions. In this context, all three archetypal A-site monocationic perovskites-CH3NH3PbI3, CH(NH2)2PbI3, and CsPbI3-suffer from either chemical or thermodynamic instabilities in their bulk form. A promising approach toward the mitigation of these challenges lies in the formation of multinary compositions (mixed cation and mixed anion). In the case of multinary colloidal NCs, such as quinary Cs xFA1- xPb(Br1- yI y)3 NCs, the outcome of the synthesis is defined by a complex interplay between the bulk thermodynamics of the solid solutions, crystal surface energies, energetics, dynamics of capping ligands, and the multiple effects of the reagents in solution. Accordingly, the rational synthesis of such NCs is a formidable challenge. Herein, we show that droplet-based microfluidics can successfully tackle this problem and synthesize Cs xFA1- xPbI3 and Cs xFA1- xPb(Br1- yI y)3 NCs in both a time- and cost-efficient manner. Rapid in situ photoluminescence and absorption measurements allow for thorough parametric screening, thereby permitting precise optical engineering of these NCs. In this showcase study, we fine-tune the photoluminescence maxima of such multinary NCs between 700 and 800 nm, minimize their emission line widths (to below 40 nm), and maximize their photoluminescence quantum efficiencies (up to 89%) and phase/chemical stabilities. Detailed structural analysis revealed that the Cs xFA1- xPb(Br1- yI y)3 NCs adopt a cubic perovskite structure of FAPbI3, with iodide anions partially substituted by bromide ions. Most importantly, we demonstrate the excellent transference of reaction parameters from microfluidics to a conventional flask-based environment, thereby enabling up-scaling and further implementation in optoelectronic devices. As an example, Cs xFA1- xPb(Br1- yI y)3 NCs with an emission maximum at 735 nm were integrated into light-emitting diodes, exhibiting a high external quantum efficiency of 5.9% and a very narrow electroluminescence spectral bandwidth of 27 nm.

Dataset Information

Highly Emissive Divalent-Ion-Doped Colloidal CsPb_1-xM_xBr₃ Perovskite Nanocrystals through Cation Exchange.

Publications

Highly Emissive Divalent-Ion-Doped Colloidal CsPb<sub>1-x</sub>M<sub>x</sub>Br<sub>3</sub> Perovskite Nanocrystals through Cation Exchange.

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