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Singha PK, Kistwal T, Datta A. Single-Particle Dynamics of ZnS Shelling Induced Replenishment of Carrier Diffusion for Individual Emission Centers in CuInS 2 Quantum Dots. J Phys Chem Lett 2023; 14:4289-4296. [PMID: 37126796 DOI: 10.1021/acs.jpclett.3c00467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Insights into blinking and photoactivation of aqueous copper indium sulfide (CIS) quantum dots have been obtained using fluorescence correlation spectroscopy (FCS) and fluorescence lifetime correlation spectroscopy (FLCS). An unusual excitation wavelength-dependence of photoactivation/photocorrosion is manifested in an increase in the initial correlation amplitude G(0) for λex = 532 nm, but a decrease for λex = 405 nm. This has been rationalized in terms of different contributions from surface-assisted recombination in the two cases. Blinking times obtained from the autocorrelation functions (ACFs) of the 100-200 ns lifetime component (core Cu-mediated recombination) are almost unaffected by shelling, but those from the ACF for the 10-30 ns lifetime (surface states) increase significantly. Absence of cross-correlation between the two recombinative states of bare CIS QDs and the emergence of an anticorrelation with the introduction of the ZnS shell are observed, indicating the diffusive nature of the two states for CIS-ZnS. The diffusion is inhibited in bare CIS QDs due to the preponderance of surface states.
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Affiliation(s)
- Prajit Kumar Singha
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Tanuja Kistwal
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Das A, Acharjee D, Panda MK, Mahato AB, Ghosh S. Dodecahedron CsPbBr 3 Perovskite Nanocrystals Enable Facile Harvesting of Hot Electrons and Holes. J Phys Chem Lett 2023; 14:3953-3960. [PMID: 37078668 DOI: 10.1021/acs.jpclett.3c00661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This Letter reports the facile harvesting of hot carriers (HCs) in a composite of 12-faceted dodecahedron CsPbBr3 nanocrystal (NC) and a scavenger molecule. We recorded ∼3.3 × 1011 s-1 HC cooling rate in NC when excited with ∼1.4 times the band gap energy (Eg), increasing to >3 × 1012 s-1 in the presence of scavengers at high concentration due to the HC extractions. Since the observed intrinsic charge transfer rate (∼1.7 × 1012 s-1) in our NC-scavenger complex is about an order of magnitude higher than the HC cooling rate (∼3.3 × 1011 s-1), carriers are harvested before their cooling. Further, a fluorescence correlation spectroscopy study reveals NC tends to form a quasi-stable complex with a scavenger molecule, ensuring charge transfer completed (τct ≈ 0.6 ps) much before the complex breaks apart (>600 μs). The overall results of our study highlight the promise shown by 12-faceted NCs and their implications in modern applications, including hot carrier solar cells.
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Affiliation(s)
- Ayendrila Das
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Debopam Acharjee
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Mrinal Kanti Panda
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Asit Baran Mahato
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Subhadip Ghosh
- School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
- Center for Interdisciplinary Sciences (CIS), National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
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Acharjee D, Das A, Panda MK, Barai M, Ghosh S. Facet Engineering for Decelerated Carrier Cooling in Polyhedral Perovskite Nanocrystals. NANO LETTERS 2023; 23:1946-1953. [PMID: 36825851 DOI: 10.1021/acs.nanolett.2c05107] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We report here the hot carrier (HC) cooling time scales within polyhedral CsPbBr3 nanocrystals (NCs) characterized by different numbers of facets (6 to 26) utilizing a femtosecond upconversion setup. Interestingly, the observed cooling time scale slows many-fold (>10 times) upon opening the new facets on the NC surface. Furthermore, a temperature-dependent study reveals that cooling in multifaceted NCs is polaron mediated, where newly opened polar facets and the soft lattice of CsPbBr3 NCs play pivotal roles. Our hallmark result of slow cooling in polyhedral NCs renders an excellent opportunity for harvesting high-energy carriers by a carefully chosen molecular system. To this end, employing the hole scavenger molecule aniline, we successfully extracted hot holes from optically pumped NCs. We believe that several intriguing properties of the polyhedral NCs, including rapid polaron formation, defect-tolerant nature, and the capability of soft lattice to support slow diffusion of charge carriers, resulted in decelerated cooling.
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Affiliation(s)
- Debopam Acharjee
- School of Chemical Sciences, National Institute of Science Education and Research, An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Ayendrila Das
- School of Chemical Sciences, National Institute of Science Education and Research, An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Mrinal Kanti Panda
- School of Chemical Sciences, National Institute of Science Education and Research, An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Manas Barai
- School of Chemical Sciences, National Institute of Science Education and Research, An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
| | - Subhadip Ghosh
- School of Chemical Sciences, National Institute of Science Education and Research, An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
- Center for Interdisciplinary Sciences (CIS), National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute (HBNI), Khurda 752050, Odisha, India
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Das S, Rana G, Ali F, Datta A. Single particle level dynamics of photoactivation and suppression of Auger recombination in aqueous Cu-doped CdS quantum dots. NANOSCALE 2023; 15:4469-4476. [PMID: 36752332 DOI: 10.1039/d2nr06688b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Cu-doped CdS quantum dots (QDs) have been synthesized in water using 3-mercaptopropionic acid (3-MPA) as the capping agent. They exhibit intense photoluminescence and excellent color tunability, unlike most of the QDs synthesized/dispersed in water so far. Complete characterization of these aqueous doped CdS QDs has been performed for the first time, along with a single particle level elucidation of their exciton dynamics using fluorescence correlation spectroscopy. Photoactivation via dim/dark to bright particle conversion is observed at higher excitation powers. Dispersive blinking kinetics in undoped QDs reflects the involvement of a broad distribution of trap states. A lesser extent of dispersity is observed for doped QDs, in which hole-capture by Cu-defect states predominates. Excitation fluence dependence of the blinking rate highlights the role of Auger recombination in undoped QDs, which is suppressed significantly upon doping, due to disruption of the electron-hole correlation.
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Affiliation(s)
- Sharmistha Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Gourab Rana
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Fariyad Ali
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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Li H, Yin W, Ng CK, Huang R, Du S, Sharma M, Li B, Yuan G, Michalska M, Matta SK, Chen Y, Chandrasekaran N, Russo S, Cameron NR, Funston AM, Jasieniak JJ. Macroporous perovskite nanocrystal composites for ultrasensitive copper ion detection. NANOSCALE 2022; 14:11953-11962. [PMID: 35899800 DOI: 10.1039/d2nr02737b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Accumulation of heavy metal ions, including copper ions (Cu2+), presents a serious threat to human health and to the environment. A substantial amount of research has focused on detecting such species in aqueous solutions. However, progress towards ultrasensitive and easy-to-use sensors for non-aqueous solutions is still limited. Here, we focus on the detection of copper species in hexane, realising ultra-sensitive detection through a fluorescence-based approach. To achieve this, a novel macroporous composite material has been developed featuring luminescent CsPbBr3 nanocrystals (NCs) chemically adhered to a polymerized high internal phase emulsion (polyHIPE) substrate through surface thiol groups. Due to this thiol functionality, sub-monolayer NC formation is realised, which also renders outstanding stability of the composite in the ambient environment. Copper detection is achieved through a direct solution based immersion of the CsPbBr3-(SH)polyHIPE composite, which results in concentration-dependent quenching of the NC photoluminescence. This newly developed sensor has a limit of detection (LOD) for copper as low as 1 × 10-16 M, and a wide operating window spanning 10-2 to 10-16 M. Moreover, the composite exhibits excellent selectivity among different transition metals.
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Affiliation(s)
- Hanchen Li
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Wenping Yin
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Chun Kiu Ng
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Ruoxi Huang
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Shengrong Du
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Manoj Sharma
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Bin Li
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Gangcheng Yuan
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
| | - Monika Michalska
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Sri Kasi Matta
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- School of Science, RMIT University, Melbourne, 3000, Australia
| | - Yu Chen
- Monash Centre for Electron Microscopy (MCEM), Monash University, Clayton, Victoria, 3800, Australia
| | - Naresh Chandrasekaran
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
| | - Salvy Russo
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- School of Science, RMIT University, Melbourne, 3000, Australia
| | - Neil R Cameron
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
- School of Engineering, University of Warwick, Coventry CV4 7AL, U.K
| | - Alison M Funston
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
| | - Jacek J Jasieniak
- Australian Research Council Centre of Excellence in Exciton Science, Australia.
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
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Mishra K, Acharjee D, Das A, Ghosh S. Femtosecond Upconversion Study of Interfacial Electron Transfer from Photoexcited CsPbBr 3 Perovskite Nanocrystal to Rhodamine 6G. J Phys Chem B 2021; 125:11017-11025. [PMID: 34583511 DOI: 10.1021/acs.jpcb.1c05354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoinduced electron transfer (PET) from an excited-state CsPbBr3 nanocrystal (NC) to rhodamine 6G (r6G) is studied in toluene using different fluorescence-based techniques. Because of weak solubility of r6G in toluene, excess r6G molecules adsorb at NC surface which result in a much slower rotational diffusion time scale of r6G in the presence of NCs. Study of intrinsic PET benefits from the soft molecular interactions leading to donor (NC)-acceptor (r6G) complex formation, where solvent diffusion parameters would not play any role in the PET kinetics. Femtosecond transients of NCs are nicely fit to a Poisson expression originally proposed by Tachiya. Conclusive fittings to the temperature dependence quenching data reveal two interesting observations: (1) Even though the average number of surface trap state in a NC does not change with temperature (5-60 °C), the trap-state-induced quenching time scale is accelerated with increase in temperature, pointing toward a more efficient trapping at higher temperature. (ii) In the presence of r6G, a fast (∼150 ps per r6G molecule) interfacial PET time scale is observed, which remains unaffected by temperature (5-60 °C). Our findings demonstrate that even a simple "perovskite NC-electron acceptor" composite like that in the present study can ensure a rapid interfacial charge separation. Such information will help us to realize the actual potential of perovskites NCs in their real applications.
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Affiliation(s)
- Krishna Mishra
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Jatni, Khurda, Odisha 752050, India
| | - Debopam Acharjee
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Jatni, Khurda, Odisha 752050, India
| | - Ayendrila Das
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Jatni, Khurda, Odisha 752050, India
| | - Subhadip Ghosh
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Jatni, Khurda, Odisha 752050, India
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