Reversible CsPbBr3 ↔ CsPb2Br5 Transformation via Reverse Micellar Aqueous Solution

Sahu, Subhashree; Debnath, Tushar; Sahu, Kalyanasis

doi:10.1021/acs.jpclett.4c00451

Cited by 3 publications

(1 citation statement)

References 28 publications

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“… 46 A few other groups also reported the optical spectra of the CsPb 2 Br 5 phase in a similar region, further strengthening our claim of formation of the CsPb 2 Br 5 phase. 47 , 48 To emphasize the generality of this chemical transformation approach, we investigated the interaction of CsPbBr 3 PNCs with other AAs, e.g., threonine, and the corresponding absorption and PL spectra are shown in Figure S2 . Similar to cysteine-treated CsPbBr 3 PNCs, both the absorption and PL spectra of the threonine-treated CsPbBr 3 PNCs depict a strong blue shift, directing the formation of CsPb 2 Br 5 NCs.…”

Section: Results and Discussionmentioning

confidence: 99%

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Agarwal,

Debnath

2024

ACS Omega

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Inspired by biomineralization, the recent incorporation of organic molecules into inorganic lattices shows interesting optical properties and tunability. We functionalize all inorganic CsPbBr 3 perovskite nanocrystals (PNCs) with amino acid (AA) cysteine using the water-hexane interfacial approach. Along with the AA cysteine, we added AuBr 3 salt into the aqueous phase, leading to the formation of a Au-cysteine thiolate complex to activate the aqueous to nonaqueous phase transportation of the AA via a molecular shuttle, oleylamine. The interaction between CsPbBr 3 PNCs and the Au-cysteine thiolate complex is probed using optical spectroscopy, which reveals dimensional reduction of the parent PNCs to form CsPbBr 3 nanoplatelets (NPls) and subsequent phase transformation to CsPb 2 Br 5 NPls. X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy conclusively support the above chemical transformation reaction via interfacial chemistry. We propose a mechanistic insight into the dimensional growth in one direction in the presence of AAs via preferential ligand binding to specific facets, leading to transformation from 3D cubes to 2D NPls, while, presumably, the phase transformation occurs via the CsBr stripping mechanism upon prolonged interaction with water. Since AAs are building blocks for several redox-active complex biological moieties, including proteins, investigation of the interaction of AAs with PNCs may be advantageous since the latter can act as a fluorescent probe for bioimaging application.

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Section: Results and Discussionmentioning

confidence: 99%

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Agarwal,

Debnath

2024

ACS Omega

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Pseudohalide Anion Passivation for Aqueous‐Stable Pure Red Perovskite Nanocrystals

Meng,

Chen,

Liu

et al. 2024

Adv Funct Materials

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Recently emerging perovskite nanocrystals (PNCs) have drawn considerable attention due to the superior optoelectronic performances. However, the terrible stability of red emissive PNCs (r‐PNCs) limits their broader application in aqueous media. Despite various encapsulation methods are proposed, the preparation of aqueous r‐PNCs with facile operation and excellent durability is still challenging. Herein, aqueous green emissive PNCs (g‐PNCs) by employing water as an external stimulus to treat oleyamine‐capped CsPbBr3 PNCs are synthesized initially, and then aqueous‐stable pure red emissive PNCs by anion‐exchange reaction and subsequently thiocyanate (SCN‐) passivation treatment (SCN‐r‐PNCs) are prepared. The obtained aqueous‐stable SCN‐r‐PNCs display high brightness, outstanding stability, and extended photoluminescence lifetime. Moreover, by combining aqueous r‐PNCs and portable smartphones, a fluorescence chemosensor for the detection of aqueous SCN− ions is constructed, which exhibits simple operation, high sensitivity, high selectivity, low detection limit, and visualized sensing. This work not only provides a new and facile strategy to prepare aqueous‐stable red emissive PNCs, but also further extends the application of red emissive PNCs in aqueous‐based fields.

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Suppression of Thermally Assisted Photoluminescence Quenching in CsPbBr₃ Nanocrystals via Surface Engineering: Implications for Optoelectronic Devices

Sen,

Karmakar,

Sarkar

et al. 2024

ACS Appl. Nano Mater.

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Lead halide perovskite (LHP) nanocrystals (NCs) are witnessing tremendous success in LED and display technology applications for their defect tolerance properties and near-unity photoluminescence quantum yield (PLQY). Despite this success, thermally assisted PL quenching in LHP NCs is a major obstacle during the operation of devices at a higher temperature. To overcome this obstacle, we have introduced an effective washing-assisted short-chain capping ligand engineering by 4-fluorobenzylammonium bromide (4FBABr) for the first time to obtain the CPB-4FBABr NC, which is simple and cost-effective. We observed a retention of about 74% PL intensity for the CPB-4FBABr NC at 373 K compared to its PL intensity at 283 K, whereas for the CPB-parent NC, only 2% of the initial PL intensity was found to be retained in the same temperature range. We argued the importance of optimum washing prior to surface engineering in this report. We also highlighted that the F-atom in 4FBABr enhances the positive charge density on the N atom of the ammonium headgroup, facilitating exceptional ligand-NC binding, while the bromide ion eliminates detrimental halide vacancy-related trap states. These two factors synergistically enhanced the heat tolerance of the engineered NC. Time-resolved PL (TRPL) measurements shed more light on the charge carrier dynamics, where shallow trap state-mediated charge carrier trapping and detrapping in the engineered NC reduced the permanent loss of excitons under extreme thermal conditions. An insight into reversibility during the cooling cycle (PL recovery by lowering the temperature) has also been established by TRPL measurements. Our findings underscore the critical role of washing before postsynthetic treatment and the effectiveness of using short-chain fluorinated aryl ammonium ligands in suppressing the thermally assisted PL quenching. This investigation will be highly beneficial to fabricating high-temperature stable perovskite-based LEDs.

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Reversible CsPbBr₃ ↔ CsPb₂Br₅ Transformation via Reverse Micellar Aqueous Solution

Cited by 3 publications

References 28 publications

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Pseudohalide Anion Passivation for Aqueous‐Stable Pure Red Perovskite Nanocrystals

Suppression of Thermally Assisted Photoluminescence Quenching in CsPbBr₃ Nanocrystals via Surface Engineering: Implications for Optoelectronic Devices

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Reversible CsPbBr3 ↔ CsPb2Br5 Transformation via Reverse Micellar Aqueous Solution

Cited by 3 publications

References 28 publications

Amino Acid-Driven Dimensional Reduction of CsPbBr3 Nanocrystals

Amino Acid-Driven Dimensional Reduction of CsPbBr3 Nanocrystals

Pseudohalide Anion Passivation for Aqueous‐Stable Pure Red Perovskite Nanocrystals

Suppression of Thermally Assisted Photoluminescence Quenching in CsPbBr3 Nanocrystals via Surface Engineering: Implications for Optoelectronic Devices

Contact Info

Product

Resources

About

Reversible CsPbBr₃ ↔ CsPb₂Br₅ Transformation via Reverse Micellar Aqueous Solution

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Amino Acid-Driven Dimensional Reduction of CsPbBr₃ Nanocrystals

Suppression of Thermally Assisted Photoluminescence Quenching in CsPbBr₃ Nanocrystals via Surface Engineering: Implications for Optoelectronic Devices