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Pathak SS, Kedarnath G, Panchakarla LS. Mechanistic Study of Amphiphilic-Assisted Self-Assembled Cadmium Sulfide Quantum Dots into 3D Superstructures. J Phys Chem Lett 2023; 14:8114-8120. [PMID: 37668342 DOI: 10.1021/acs.jpclett.3c02180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Self-assembling of nanoparticles into complex superstructures is very challenging, which usually depends on postorganizing techniques or pre-existing templates such as polypeptide chains or DNA or external stimulus. Such self-assembled processes typically lead to close-packed structures. Here, it has been demonstrated that under carefully template-free reaction conditions CdS quantum dots (QDs) could be synthesized and simultaneously self-assembled into complex superstructures without compromising individual QD properties. The superstructures of CdS QDs attained by the chemical-based method demonstrate Stokes-shifted photoluminescence (PL) from trap states. Remarkably, the PL decay of superstructures exhibits a single-exponential feature. This behavior is unusual for the synthesized superstructures, indicating that the trap states are restricted to a narrow range. The growth mechanism of these superstructures is explained through the formation of liquid crystal phases (LCPs) with the help of a small-angle X-ray scattering (SAXS) analysis.
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Affiliation(s)
- Sushil Swaroop Pathak
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Gotluru Kedarnath
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Leela S Panchakarla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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2
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Shulenberger KE, Jilek MR, Sherman SJ, Hohman BT, Dukovic G. Electronic Structure and Excited State Dynamics of Cadmium Chalcogenide Nanorods. Chem Rev 2023; 123:3852-3903. [PMID: 36881852 DOI: 10.1021/acs.chemrev.2c00676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The cylindrical quasi-one-dimensional shape of colloidal semiconductor nanorods (NRs) gives them unique electronic structure and optical properties. In addition to the band gap tunability common to nanocrystals, NRs have polarized light absorption and emission and high molar absorptivities. NR-shaped heterostructures feature control of electron and hole locations as well as light emission energy and efficiency. We comprehensively review the electronic structure and optical properties of Cd-chalcogenide NRs and NR heterostructures (e.g., CdSe/CdS dot-in-rods, CdSe/ZnS rod-in-rods), which have been widely investigated over the last two decades due in part to promising optoelectronic applications. We start by describing methods for synthesizing these colloidal NRs. We then detail the electronic structure of single-component and heterostructure NRs and follow with a discussion of light absorption and emission in these materials. Next, we describe the excited state dynamics of these NRs, including carrier cooling, carrier and exciton migration, radiative and nonradiative recombination, multiexciton generation and dynamics, and processes that involve trapped carriers. Finally, we describe charge transfer from photoexcited NRs and connect the dynamics of these processes with light-driven chemistry. We end with an outlook that highlights some of the outstanding questions about the excited state properties of Cd-chalcogenide NRs.
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Affiliation(s)
| | - Madison R Jilek
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Skylar J Sherman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Benjamin T Hohman
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Gordana Dukovic
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States.,Materials Science and Engineering, University of Colorado Boulder, Boulder, Colorado 80303, United States
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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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Gogoi H, Pathak SS, Dasgupta S, Panchakarla LS, Nath S, Datta A. Exciton Dynamics in Colloidal CdS Quantum Dots with Intense and Stokes Shifted Photoluminescence in a Single Decay Channel. J Phys Chem Lett 2022; 13:6770-6776. [PMID: 35853205 DOI: 10.1021/acs.jpclett.2c01623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
CdS quantum dots (QDs), synthesized by a sol-gel method, exhibit significantly Stokes shifted bright photoluminescence (PL), predominantly from the trap states. Surprisingly, the PL decay at the emission maximum is single-exponential. This is an unusual observation for as-prepared QDs and indicates a narrow distribution in the nature of trap states. A closer look reveals an additional fast component for the decays at shorter emission wavelengths, presumably due to the band edge emission, which remains elusive in the steady-state spectra. Indeed, a significantly narrower and blue-shifted emission band is observed in the decay-associated spectra. The contribution of this component to the steady-state PL intensity is shown to be overwhelmed by that of the significantly stronger trap emission. Exciton dynamics in the quantum dots is elucidated using transient absorption spectra, in which the stimulated emission is observed even at low pump power.
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Affiliation(s)
- Hemen Gogoi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sushil Swaroop Pathak
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Souradip Dasgupta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - Sukhendu Nath
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400 094, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Gogoi H, Maddala BG, Ali F, Datta A. Role of Solvent in Electron-Phonon Relaxation Dynamics in Core-Shell Au-SiO 2 Nanoparticles. Chemphyschem 2021; 22:2201-2206. [PMID: 34402561 DOI: 10.1002/cphc.202100592] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Indexed: 01/03/2023]
Abstract
Relaxation dynamics of plasmons in Au-SiO2 core-shell nanoparticles have been followed by femtosecond pump-probe technique. The effect of excitation pump energy and surrounding medium on the time constants associated with the hot electron relaxation has been elucidated. A gradual increase in the electron-phonon relaxation time with pump energy is observed and can be attributed to the higher perturbation of the electron distribution in AuNPs at higher pump energy. Variation in time constants for the electron-phonon relaxation in different solvents is rationalized on the basis of their thermal conductivities, which govern the rate of dissipation of heat of photoexcited electrons in the nanoparticles. On the other hand, phonon-phonon relaxation is found to be much less effective than electron-phonon relaxation for the dissipation of energy of the excited electron and the time constants associated with it remain unaffected by thermal conductivity of the solvent.
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Affiliation(s)
- Hemen Gogoi
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Bala Gopal Maddala
- Department of Chemistry, IIT Bombay, IITB-Monash Research Academy, Mumbai, 400076, India
| | - Fariyad Ali
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Anindya Datta
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
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Ali F, Das S, Banerjee S, Maddala BG, Rana G, Datta A. Intense photoluminescence from Cu-doped CdSe nanotetrapods triggered by ultrafast hole capture. NANOSCALE 2021; 13:14228-14235. [PMID: 34477705 DOI: 10.1039/d1nr03833h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Brightly photoluminescent Cu-doped CdSe nanotetrapods (NTPs) have been prepared by a modified hot injection method. Their photoluminescence (PL) has a quantum yield of 38% and decays slowly over a few microseconds, while the PL in undoped NTPs has a rather small quantum yield of 1.7% and decays predominantly in tens of picoseconds, with a minor component in the nanosecond time regime. PL spectra of doped NTPs are significantly Stokes shifted compared to the band edge (BE). Efficient PL quenching by a hole scavenger confirms the oxidation state of +I for the dopant ion and establishes hole capture by this ion to be the primary event that leads to the Stokes shifted PL. A fast decay of the photoinduced absorption band, along with a similar decay in PL, observed in a femtosecond optical gating experiment, yields a time constant of about a picosecond for the hole capture from the valence band (VB) by Cu+. The remarkably long PL lifetime in the doped NTPs is ascribed to the decrease in the overlap between the wavefunctions of the photogenerated electrons and the captured hole. Hot carrier relaxation processes, triggered by excitation at energies greater than the band gap, leave their signature in a rise time of few hundreds of femtoseconds, in the ground state bleach recovery kinetics. Hence, a complete picture of exciton dynamics in the doped NTPs has been obtained using ultrafast spectroscopic techniques working in tandem.
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Affiliation(s)
- Fariyad Ali
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
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Laxman K, Reddy BPK, Mishra SK, Gopal MB, Robinson A, De A, Srivastava R, Ravikanth M. BF 2-Oxasmaragdyrin Nanoparticles: A Non-toxic, Photostable, Enhanced Non-radiative Decay-Assisted Efficient Photothermal Cancer Theragnostic Agent. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52329-52342. [PMID: 33170618 DOI: 10.1021/acsami.0c13326] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photothermal therapy (PTT), a simple and minimally invasive procedure, is an attractive option for cancer therapy. To date, inorganic agents have been widely employed as photothermal agents; however, organic molecules may provide a solution to rapid metabolic/in vivo clearance. Herein, we prepared lipid (S 75)-stabilized meso-tritolyl-BF2-oxasmaragdyrin nanoparticles (TBSNPs) using thin-film hydration and homogenization. Assessment of the physicochemical properties of the TBSNPs reveals the formation of particles of size <12 nm stabilized within the lipid matrix. The TBSNPs exhibit near infrared fluorescence (NIRF) being accompanied by an increase in non-radiative decay, leading to excellent photothermal properties. In vitro studies demonstrate excellent biocompatibility, hemocompatibility, cellular internalization, and photothermal efficacy (p = 0.0004). Extensive in vivo assessment of TBSNPs also highlights the non-toxic nature of the material and passive tumor homing. The strong NIRF exhibited by the material is exploited for whole-body imaging in the rodent model. The novel material also shows excellent photothermal efficacy (p = 0.0002) in a 4T1 xenograft mice model. The organic nature of the material coupled with its small size and strong NIRF provides an advantage for bio-elimination and potential clinical image-guided therapy over the inorganic counterparts.
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Affiliation(s)
- Kandala Laxman
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
- School of Chemistry, Monash University, (Building 23, Room 114C), Wellington Road Clayton, Melbourne, Victoria 3800, Australia
| | - B Pradeep K Reddy
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sumit K Mishra
- Molecular Functional Imaging Laboratory, ACTREC, Tata Memorial Centre, Kharghar, Navi Mumbai 410210, India
- Department of Life Sciences, Homi Bhabha National Institute, BARC Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Maddala Bala Gopal
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Andrea Robinson
- School of Chemistry, Monash University, (Building 23, Room 114C), Wellington Road Clayton, Melbourne, Victoria 3800, Australia
| | - Abhijit De
- Molecular Functional Imaging Laboratory, ACTREC, Tata Memorial Centre, Kharghar, Navi Mumbai 410210, India
- Department of Life Sciences, Homi Bhabha National Institute, BARC Training School Complex, Anushaktinagar, Mumbai 400094, India
| | - Rohit Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Banerjee S, Kistwal T, Sajeevan A, Datta A. Release of Warfarin from Human Serum Albumin by Water‐soluble CdSe Nanotetrapods. Chemphyschem 2020; 21:2709-2714. [DOI: 10.1002/cphc.202000292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/27/2020] [Indexed: 01/03/2023]
Affiliation(s)
- Sucheta Banerjee
- Department of Chemistry Indian Institute of Technology Bombay Powai, Mumbai 400 076 India
| | - Tanuja Kistwal
- Department of Chemistry Indian Institute of Technology Bombay Powai, Mumbai 400 076 India
| | - Amritha Sajeevan
- Department of Chemical Sciences Indian Institute of Science Education and Research Kolkata Campus Rd Mohanpur, West Bengal 741246 India
| | - Anindya Datta
- Department of Chemistry Indian Institute of Technology Bombay Powai, Mumbai 400 076 India
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Rakshit S, Das S, Govindaraj V, Maini R, Kumar A, Datta A. Morphological Evolution of Strongly Fluorescent Water Soluble AIEEgen-Triblock Copolymer Mixed Aggregates with Shape-Dependent Cell Permeability. J Phys Chem B 2020; 124:10282-10291. [PMID: 33135898 DOI: 10.1021/acs.jpcb.0c07820] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dimethyl-2,5-bis(4-methoxyphenylamino)terephthalate (DBMPT) is a water-insoluble fluorogenic molecule, which has been rendered water-soluble in physiological conditions, by the addition of triblock copolymers (TBPs), P123 (PEO19PPO69PEO19), and F127 (PEO100PPO65PEO100). DBMPT-TBP mixed aggregates, formed in the process, exhibit significant aggregation-induced enhancement of emission, with nanosecond fluorescence lifetimes. Dynamics involved in suppression of nonradiative pathways and consequent enhancement of fluorescence are followed by femtosecond transient absorption and time-resolved fluorescence spectroscopic techniques. Interestingly, shapes of the aggregates formed with the two TBPs are found to be very different, even though they differ only in the length of hydrophilic blocks. DBMPT-P123 aggregates are micrometer-sized and spherical, while DBMPT-F127 aggregates form nanorods. Evolution of their morphologies, as a function of TBP concentration, is monitored using cryo-TEM, FESEM, and fluorescence lifetime imaging microscopy. Fluorescence lifetime distribution provides useful insight into microheterogeneity in these mixed aggregates. Excellent cell permeability is observed for DBMPT-F127 nanorods, in contrast to DBMPT-P123 microspheres. These fluorescent nanorods exhibit the ability to mark lipid droplets within the cell and hence bear the promise for application in intracellular imaging.
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Affiliation(s)
- Soumyadipta Rakshit
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Sharmistha Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Vinodhini Govindaraj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Ratika Maini
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Anil Kumar
- 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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