Fast, tunable and reversible anion-exchange in CsPbBr<sub>3</sub> perovskite nanocrystals with hydrohalic acids

Dutt, V. G. Vasavi; Akhil, Syed; Mishra, Nimai

doi:10.1039/d0ce00722f

Cited by 46 publications

(52 citation statements)

References 40 publications

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“…Moreover, Akkerman et al noted that, starting from CsPbBr 3 nanocrystals, the PLQY after exchange to CsPbCl 3 or CsPbI 3 dropped to values that were in line with those of as-prepared and CsPbCl 3 or CsPbI 3 nanocrystals, which are generally less bright than CsPbBr 3 nanocrystals. 2 In addition, Mishra et al, when performing a CsPbBr 3 → CsPbCl 3 anion exchange on nanocrystals and then the inverse CsPbCl 3 → CsPbBr 3 reaction, 23 noted that the PLQY of the final CsPbBr 3 nanocrystals was even higher than that of the initial sample. That result suggests that the creation of additional defects is unlikely.…”

Section: Changing Color By Ion Exchangementioning

confidence: 99%

Metamorphoses of Cesium Lead Halide Nanocrystals

2021

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Conspectus Following the impressive development of bulk lead-based perovskite photovoltaics, the “perovskite fever” did not spare nanochemistry. In just a few years, colloidal cesium lead halide perovskite nanocrystals have conquered researchers worldwide with their easy synthesis and color-pure photoluminescence. These nanomaterials promise cheap solution-processed lasers, scintillators, and light-emitting diodes of record brightness and efficiency. However, that promise is threatened by poor stability and unwanted reactivity issues, throwing down the gauntlet to chemists. More generally, Cs–Pb–X nanocrystals have opened an exciting chapter in the chemistry of colloidal nanocrystals, because their ionic nature and broad diversity have challenged many paradigms established by nanocrystals of long-studied metal chalcogenides, pnictides, and oxides. The chemistry of colloidal Cs–Pb–X nanocrystals is synonymous with change: these materials demonstrate an intricate pattern of shapes and compositions and readily transform under physical stimuli or the action of chemical agents. In this Account, we walk through four types of Cs–Pb–X nanocrystal metamorphoses: change of structure, color, shape, and surface. These transformations are often interconnected; for example, a change in shape may also entail a change of color. The ionic bonding, high anion mobility due to vacancies, and preservation of cationic substructure in the Cs–Pb–X compounds enable fast anion exchange reactions, allowing the precise control of the halide composition of nanocrystals of perovskites and related compounds (e.g., CsPbCl 3 ⇄ CsPbBr 3 ⇄ CsPbI 3 and Cs 4 PbCl 6 ⇄ Cs 4 PbBr 6 ⇄ Cs 4 PbI 6 ) and tuning of their absorption edge and bright photoluminescence across the visible spectrum. Ion exchanges, however, are just one aspect of a richer chemistry. Cs–Pb–X nanocrystals are able to capture or release (in short, trade) ions or even neutral species from or to the surrounding environment, causing major changes to their structure and properties. The trade of neutral PbX 2 units allows Cs–Pb–X nanocrystals to cross the boundaries among four different types of compounds: 4CsX + PbX 2 ⇄ Cs 4 PbBr 6 + 3PbX 2 ⇄ 4CsPbBr 3 + PbX 2 ⇄ 4CsPb 2 X 5 . These reactions do not occur at random, because the reactant and product nanocrystals are connected by the Cs + cation substructure preservation principle, stating that ion trade reactions can transform one compound into another by means of distorting, expanding, or contracting their shared Cs + cation substructu...

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Section: Changing Color By Ion Exchangementioning

confidence: 99%

Metamorphoses of Cesium Lead Halide Nanocrystals

2021

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“…Three different surface chemistry-based CsPbBr3 perovskite was synthesized according to the reported hot injection method with a slight modification. 46,47 Briefly amine-free-CsPbBr3 perovskite nanocrystals were prepared by a modified three-precursor approach in which the Cs, Pb, and Br precursors are used independently. Amine free-CsPbBr3 PNCs were synthesized in presence of oleic acid (OA) and trioctylphosphine (TOP) as surface capping ligands.…”

Section: Resultsmentioning

confidence: 99%

Surface modification for improving the photoredox activity of CsPbBr₃nanocrystals

2021

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“…FTIR spectroscopy was used to characterize the surface of NCs and gain insighti nto surface-ligand interactions of phosphane-based surfactants (F igure 7). We compared FTIR spectra of CsPbBr 3 NCs synthesized with OA/OAm ligands in open air withoutd egassing steps [40] and with the completely amine-free OA/TOP-capped NCs reported in this work. For the conventional CsPbBr 3 NCs, the peaks at 1643 and 1547 cm À1 indicatet he presence of OA and OAm ligands, respectively.T he stretching vibration at 1718 cm À1 corresponds to C=Oo fo leate.…”

Section: Resultsmentioning

confidence: 99%

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

Akhil

Dutt

Mishra

2020

Chemistry A European J

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Cesium lead halide perovskite nanocrystals (NCs) CsPbX3 (X=Cl, Br, and I) have been prominent materials in the last few years due to their high photoluminescence quantum yield (PLQY) for light‐emitting diodes and other significant applications in photovoltaics and optoelectronics. In colloidal CsPbX3 synthesis, the most commonly used ligands are oleic acid and oleylamine. The latter plays an important role in surface passivation but may also be responsible for poor colloidal stability as a result of facile proton exchange leading to the formation of labile oleylammonium halide, which pulls halide ions out of the NC surface. Herein, a facile, efficient, completely amine‐free synthesis of cesium lead bromide perovskite nanocrystals using hydrobromic acid as halide source and tri‐n‐octylphosphane as ligand under open‐atmospheric conditions is demonstrated. Hydrobromic acid serves as labile source of bromide ion, and thus this three‐precursor approach (separate precursors for Cs, Pb, Br) gives more control than a conventional single‐source precursor for Pb and Br (PbBr2). The use of HBr paved the way to eliminate oleylamine, and thus the formation of labile oleylammonium halide can be completely excluded. Various Cs:Pb:Br molar ratios were studied and optimum conditions for making very stable CsPbBr3 NCs with high PLQY were found. These completely amine‐free CsPbBr3 perovskite NCs synthesized under bromine‐rich conditions exhibit good stability and durability for more than three months in the form of colloidal solutions and films, respectively. Furthermore, stable tunable emission across a wide spectral range through anion exchange was demonstrated. More importantly, this work reports open‐atmosphere‐stable CsPbBr3 NCs films exhibiting strong PL, which can be further used for optoelectronic device applications.

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Fast, tunable and reversible anion-exchange in CsPbBr₃ perovskite nanocrystals with hydrohalic acids

Abstract: Anion-exchange with metal chloride salts in CsPbBr3 perovskite nanocrystals.

Cited by 46 publications

References 40 publications

Metamorphoses of Cesium Lead Halide Nanocrystals

Metamorphoses of Cesium Lead Halide Nanocrystals

Surface modification for improving the photoredox activity of CsPbBr₃nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals

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Fast, tunable and reversible anion-exchange in CsPbBr3 perovskite nanocrystals with hydrohalic acids

Abstract: Anion-exchange with metal chloride salts in CsPbBr3 perovskite nanocrystals.

Cited by 46 publications

References 40 publications

Metamorphoses of Cesium Lead Halide Nanocrystals

Metamorphoses of Cesium Lead Halide Nanocrystals

Surface modification for improving the photoredox activity of CsPbBr3nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr3) Perovskite Nanocrystals

Contact Info

Product

Resources

About

Fast, tunable and reversible anion-exchange in CsPbBr₃ perovskite nanocrystals with hydrohalic acids

Surface modification for improving the photoredox activity of CsPbBr₃nanocrystals

Completely Amine‐Free Open‐Atmospheric Synthesis of High‐Quality Cesium Lead Bromide (CsPbBr₃) Perovskite Nanocrystals