Revisiting the origin of green emission in Cs<sub>4</sub>PbBr<sub>6</sub>

Biswas, Koushik

doi:10.1039/d2ma00544a

Cited by 3 publications

(3 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[ 32 ] The associated below‐gap green photoluminescence (signifying the possibility of a population inversion) with a high quantum yield has been the subject of extensive studies. [ 33 ] We speculate that the lack of such lower‐energy emission centers and the low photoluminescence quantum yield (as a result of molecular‐type [Bi 2 I 9 ] 3− excitons and high nonradiative recombination) would be the fundamental bottlenecks for the use of Cs 3 Bi 2 I 9 as a lasing or photovoltaic material. Knowing that quantum dots of the bromide counterpart show more than two orders‐of‐magnitude higher photoluminescence quantum yield than the iodide compound, [ 34 ] it may be important to study the carrier–lattice coupling and structural dynamics of Cs 3 Bi 2 Br 9 , which could exhibit crucial behavioral differences as a result of the nature of bonding in the [Bi 2 Br 9 ] 3− unit.…”

Section: Discussionmentioning

confidence: 99%

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Tailor

Satapathi

et al. 2023

Advanced Optical Materials

View full text Add to dashboard Cite

To assess the potential optoelectronic applications of metal‐halide perovskites, it is critical to have a detailed understanding of the nature and dynamics of interactions between carriers and the polar lattices. Here, the electronic and structural dynamics of bismuth‐based perovskite Cs3Bi2I9 are revealed by transient reflectivity and ultrafast electron diffraction. A cross‐examination of these results combined with theoretical analyses allows the identification of the major carrier–phonon coupling mechanism and the associated time scales. It is found that carriers photoinjected into Cs3Bi2I9 form self‐trapped excitons on an ultrafast time scale. However, they retain most of their energy, and their coupling to Fröhlich‐type optical phonons is limited at early times. Instead, the long‐lived excitons exert an electronic stress via deformation potential and develop a prominent, sustaining strain field as coherent acoustic phonons in 10 ps. From sub‐ps to ns and beyond, a similar extent of the atomic displacements is found throughout the different stages of structural distortions, from limited local modulations to a coherent strain field to the Debye–Waller random atomic motions on longer times. The current results suggest the potential use of bismuth‐based perovskites for applications other than photovoltaics to take advantage of the carriers’ stronger self‐trapping and long lifetimes.

show abstract

Section: Discussionmentioning

confidence: 99%

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Tailor

Satapathi

et al. 2023

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…A zero-dimensional (0D) halide perovskite, Cs 4 PbBr 6 , is being investigated as a light emitter. There is accompanying debate regarding the emission center and luminescence mechanism . It has a disjointed crystal structure where the (apparently) isolated [PbBr 6 ] octahedra offer various ways in which an excited charge carrier may be trapped.…”

mentioning

confidence: 99%

“…There is accompanying debate regarding the emission center and luminescence mechanism. 1 It has a disjointed crystal structure where the (apparently) isolated [PbBr 6 ] octahedra offer various ways in which an excited charge carrier may be trapped. Those traps can create strongly bound states inside the band gap of this material.…”

mentioning

confidence: 99%

Case of the Bromine Vacancy in Cs₄PbBr₆

Kang,

Biswas

2023

J. Phys. Chem. Lett.

Self Cite

View full text Add to dashboard Cite

Typically defect tolerance is equated with a lack of deleterious defects or with abundant defects creating only shallow levels. Here, we address the idea that deep defects, when unavoidable, do not guarantee harmful consequences. Using halogen vacancy as a common defect among halides, we explore its behavior in Cs 4 PbBr 6 . It is a large gap material (band gap of ∼4 eV) known for its green emission at ∼520 nm. We show that its Br-vacancy is indeed a deep defect as obtained from hybrid density functional calculations. An analysis of the configuration coordinate diagram corresponding to the defect's charge transition levels enables us to conclude that the nonradiative recombination cycle will be hampered by an extremely slow hole capture process. Therefore, Br-vacancy will not suppress light emission in Cs 4 PbBr 6 . Although this finding does not signal that all deep defects will behave similarly, it indicates that defect tolerance may be achievable despite their occurrence.

show abstract

Tunable Emissive CsPbBr₃/Cs₄PbBr₆ Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field‐Effect Phototransistors

Han,

Wan,

et al. 2024

Advanced Science

View full text Add to dashboard Cite

Precise control of quantum structures in hybrid nanocrystals requires advancements in scientific methodologies. Here, on the design of tunable CsPbBr3/Cs4PbBr6 quantum dots are reported by developing a unique discrete phase transformation approach in Cs4PbBr6 nanocrystals. Unlike conventional hybrid systems that emit solely in the green region, this current strategy produces adjustable luminescence in the blue (450 nm), cyan (480 nm), and green (510 nm) regions with high photoluminescence quantum yields up to 45%, 60%, and 85%, respectively. Concentration‐dependent studies reveal that phase transformation mechanisms and the factors that drive CsBr removal occur at lower dilutions while the dissolution–recrystallization process dominates at higher dilutions. When the polymer‐CsPbBr3/Cs4PbBr6 integrated into a field‐effected transistor the resulting phototransistors featured enhanced photosensitivity exceeding 105, being the highest reported for an n‐type phototransistor, while maintaining good transistor performances as compared to devices consisting of polymer‐CsPbBr3 NCs.

show abstract

Revisiting the origin of green emission in Cs₄PbBr₆

Abstract: It is probably acceptable to state that the recent debate over the origin of green emission in Cs4PbBr6 and/or CsPbBr3 has been narrowed down to two major possibilities: (i) a...

Cited by 3 publications

References 78 publications

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Case of the Bromine Vacancy in Cs₄PbBr₆

Tunable Emissive CsPbBr₃/Cs₄PbBr₆ Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field‐Effect Phototransistors

Contact Info

Product

Resources

About

Revisiting the origin of green emission in Cs4PbBr6

Abstract: It is probably acceptable to state that the recent debate over the origin of green emission in Cs4PbBr6 and/or CsPbBr3 has been narrowed down to two major possibilities: (i) a...

Cited by 3 publications

References 78 publications

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs3Bi2I9

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs3Bi2I9

Case of the Bromine Vacancy in Cs4PbBr6

Tunable Emissive CsPbBr3/Cs4PbBr6 Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field‐Effect Phototransistors

Contact Info

Product

Resources

About

Revisiting the origin of green emission in Cs₄PbBr₆

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Strong Coupling of Self‐Trapped Excitons to Acoustic Phonons in Bismuth Perovskite Cs₃Bi₂I₉

Case of the Bromine Vacancy in Cs₄PbBr₆

Tunable Emissive CsPbBr₃/Cs₄PbBr₆ Quantum Dots Engineered by Discrete Phase Transformation for Enhanced Photogating in Field‐Effect Phototransistors