Article
Multidisciplinary Sciences
Herath P. Piyathilaka, Rishmali Sooriyagoda, Hamidreza Esmaielpour, Vincent R. Whiteside, Tetsuya D. Mishima, Michael B. Santos, Ian R. Sellers, Alan D. Bristow
Summary: The research focuses on the photoexcited carrier dynamics in InAs/AlAs0.16Sb0.84 multiple-quantum well sample, revealing significant influences of excitation photon energy and lattice temperature on transient terahertz absorption. With sufficient excess-photon energy, the metastable state transitions to long-lived states. As temperature increases, the long-lived decay times also increase.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Multidisciplinary
Alexandra Brumberg, Nicolas E. Watkins, Benjamin T. Diroll, Richard D. Schaller
Summary: Colloidal semiconductor nanocrystals, such as CdSe nanoplatelets and quantum dots, offer advantages in optoelectronics but are affected by rapid nonradiative Auger recombination at high excitation intensities. This study investigates the temperature dependence of excited state lifetime and fluence-dependent emission, revealing fundamental differences between CdSe nanoplatelets and core-only quantum dots, and highlighting the increased utility of photogenerated excitons and multiexcitons at low temperatures.
Article
Optics
Junhong Yu, Manoj Sharma, Mingjie Li, Savas Delikanli, Ashma Sharma, Muhammad Taimoor, Yemliha Altintas, James R. McBride, Thomas Kusserow, Tze-Chien Sum, Hilmi Volkan Demir, Cuong Dang
Summary: This study systematically investigates the optical gain properties of copper-doped CdSe colloidal quantum wells for the first time, revealing that an optimal amount of copper dopants can result in the lowest amplified spontaneous emission threshold and improve the performance of colloidal-based lasers.
LASER & PHOTONICS REVIEWS
(2021)
Article
Materials Science, Multidisciplinary
Andrew A. Marder, James Cassidy, Dulanjan Harankahage, Jacob Beavon, Luis Gutierrez-Arzaluz, Omar F. Mohammed, Aditya Mishra, Austen C. Adams, Jason. D. Slinker, Zhongjian Hu, Stephen Savoy, Mikhail Zamkov, Anton V. Malko
Summary: Compared to zero-dimensional (0D) semiconductor quantum dots, 2D semiconductor nanoplatelets (NPLs) offer a spectrally narrow luminescence and superior absorption coefficients. However, optical devices based on NPLs still suffer from nonradiative Auger decay, which limits the efficiency of various processes. In this study, it is demonstrated that Auger recombination is strongly suppressed in spherically shaped nanoplatelets called quantum shells (QSs), leading to improved performance in terms of biexciton emission yield, amplified spontaneous emission, and electroluminescence enhancement. These results are significant for the development of solution-processed colloidal lasers and LEDs.
ACS MATERIALS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Hongyu Yang, Si Li, Lei Zhang, Wenbin Xiang, Yi Zhang, Xiaoyong Wang, Min Xiao, Yiping Cui, Jiayu Zhang
Summary: Semiconductor quantum dots have advantages in optoelectronic devices, but charged exciton states are unavoidable. This study synthesized CdSe/CdZnS/ZnS core/alloy shell/shell quantum dots with high photoluminescence quantum yield and systematically studied their multiexciton spectra and dynamics. The results showed that the band-edge biexciton is influenced by Coulomb interaction and Stark effect. A vertical microcavity surface-emitting laser device was fabricated using these quantum dots.
Article
Chemistry, Physical
Z. Ouzit, G. Baillard, J. Liu, B. Wagnon, L. Guillemeney, B. Abecassis, L. Coolen
Summary: This study compares the luminescence decay dynamics of single CdSe nanoplatelets, clusters of a few platelets, and self-assembled chains. The luminescence decay becomes faster as the number of stacked platelets increases, indicating the FRET-mediated effect of quenchers. Additionally, a slow decay component is observed for both single platelets and platelet chains, suggesting trapping-detrapping mechanisms in nearby trap states. Toy models are developed to analyze the effects of FRET-mediated quenching and trapping on decay curves.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Junhong Yu, Manoj Sharma, Mingjie Li, Baiquan Liu, Pedro Ludwig Hernandez-Martinez, Savas Delikanli, Ashma Sharma, Yemliha Altintas, Chathuranga Hettiarachchi, Tze Chien Sum, Hilmi Volkan Demir, Cuong Dang
Summary: In this study, Cu-doped CdSe colloidal quantum wells were found to exhibit continuous-wave pumped high-order excitonic emission with a large binding energy at room temperature. This unique behavior is attributed to the dopant excitons, which have ultralong lifetimes and highly localized wavefunctions that facilitate the formation of many-body correlations. This research may pave the way for novel solution-processed solid-state devices.
CELL REPORTS PHYSICAL SCIENCE
(2022)
Article
Chemistry, Physical
Dongmei Xiang, Yulu Li, Lifeng Wang, Tao Ding, Junhui Wang, Kaifeng Wu
Summary: In this study, the electron and hole spin dynamics in CdSe colloidal nanoplatelets of varying thicknesses were investigated using circularly polarized transient absorption spectroscopy. The results showed that hole spin-flip occurred within 200 fs, while the electron spin lifetime decreased as the platelet thickness was reduced. The findings suggest an exchange interaction between the electron and the hole, and/or surface dangling bond spins enhanced by quantum confinement.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Nima Taghipour, Mariona Dalmases, Guy L. Whitworth, Miguel Dosil, Andreas Othonos, Sotirios Christodoulou, Shanti Maria Liga, Gerasimos Konstantatos
Summary: This study utilizes PbS/PbSSe core/alloyed-shell colloidal quantum dots (CQDs) as a gain medium for infrared laser devices. The researchers achieved highly suppressed Auger recombination and lower amplified spontaneous emission (ASE) threshold by doping these engineered CQDs and successfully achieved near-infrared laser emission.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xiaoqi Hou, Haiyan Qin, Xiaogang Peng
Summary: Auger recombination is effectively reduced in high-quality quantum dots by enhancing dielectric screening of band-edge carriers with additional ZnS shells. The volume scaling of negative-trion Auger lifetime is achieved with ZnS shells, which can be less than half the volume of QDs without these shells, while also enhancing the biexciton emission quantum yield. The engineering of Auger effects through dielectric screening presents new opportunities for improving emission properties in multicarrier states of quantum dots.
Article
Chemistry, Physical
Arun Ashokan, Paul Mulvaney
Summary: Solution-phase spectroelectrochemistry was used to study electron injection into colloidal CdSe quantum dots in THF. The results showed reversible optical changes on a time-scale of minutes, with the injection of electrons leading to quenching of photoluminescence. The number of electrons injected into the QDs depended on the electrode potential and QD size, with most injection occurring below the band edge.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Lifeng Wang, Dongmei Xiang, Kaimin Gao, Junhui Wang, Kaifeng Wu
Summary: Colloidal n-doped CdSe and CdSe/ZnS nanoplatelets have been achieved through a photochemical doping method, demonstrating successful additional electron doping at the conduction band edge. The key to successful doping lies in a high surface ligand coverage, while unpassivated surface cations may lead to depletion of the doped electrons.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Review
Chemistry, Physical
Zhaohan Li, Jing Wei, Fangfang Wang, Yanan Tang, Anming Li, Yating Guo, Pan Huang, Sergio Brovelli, Huaibin Shen, Hongbo Li
Summary: Light-emitting devices based on alloyed quantum dots have achieved high external quantum efficiencies and are considered promising candidates for next generation solid-state lighting and displays. The advantages of these devices stem from the chemical composition gradient of the alloyed quantum dots, which release lattice strain and reduce interface defects. Understanding carrier dynamics in quantum dots is crucial for their fundamental properties and functionalities, and further research is encouraged to improve control of carrier dynamics in alloyed quantum dots.
ADVANCED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Ivo Tanghe, Justinas Butkus, Kai Chen, Ronnie R. Tamming, Shalini Singh, Yera Ussembayev, Kristiaan Neyts, Dries van Thourhout, Justin M. Hodgkiss, Pieter Geiregat
Summary: The refractive index change of 2D semiconductors is crucial for realizing various photonic devices. By utilizing femtosecond interferometry and effective medium algorithm, the time-dependent refractive index of colloidal 2D materials can be measured and calculated, showing significant phase modulation due to excitonic features.
Article
Chemistry, Multidisciplinary
Jayanta Dana, Omer S. Haggag, Joanna Dehnel, Morin Mor, Efrat Lifshitz, Sanford Ruhman
Summary: Numerous studies have shown that core CdSe nanocrystals do not exhibit state filling in 1S(h), which has significant implications in light-emitting applications. By conducting spectroscopy experiments on CdSe crystals with organic ligands, it was observed that there is no rapid filling effects of hole states in transient absorption measurements.
Article
Chemistry, Multidisciplinary
Chentao Li, Xin Lu, Ajit Srivastava, S. David Storm, Rachel Gelfand, Matthew Pelton, Maxim Sukharev, Hayk Harutyunyan
Summary: This study presents the first experimental investigation of the nonlinear properties of monolayer transition metal dichalcogenides coupled to metal plasmonic nanocavities, showing a pronounced splitting in the pump-frequency dependence of the second-harmonic signal. Numerical simulations utilizing a nonperturbative nonlinear hydrodynamic model of conduction electrons support this interpretation and reproduce experimental results.
Article
Optics
Daehan Yoo, Fernando de Leon-Perez, Matthew Pelton, In-Ho Lee, Daniel A. Mohr, Markus B. Raschke, Joshua D. Caldwell, Luis Martin-Moreno, Sang-Hyun Oh
Summary: Research demonstrates that ultrastrong coupling between phonons and gap plasmons in nanocavities can lead to a modal splitting of up to 50% of the resonant frequency, opening up new possibilities for ultrastrong coupling applications.
Article
Chemistry, Physical
Zachary T. Brawley, S. David Storm, Diego A. Contreras Mora, Matthew Pelton, Matthew Sheldon
Summary: The vibrational strong coupling of molecules to optical cavities based on plasmonic resonances has been explored recently due to the ability of plasmonic near-fields to provide strong coupling in sub-diffraction limited volumes. This work demonstrates an angle-independent plasmonic nanodisk substrate that overcomes limitations of traditional optical cavities and allows for strong coupling with all molecules on the surface, regardless of molecular orientation. The large linewidths of the plasmon resonance enable simultaneous strong coupling to two orthogonal water vibrational modes, with the Rabi splitting varying as a function of plasmon frequency and strong coupling achieved for a range of diameters.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Daehan Yoo, Avijit Barik, Fernando de Leon-Perez, Daniel A. Mohr, Matthew Pelton, Luis Martin-Moreno, Sang-Hyun Oh
Summary: The integration of plasmonics and electronics on a chip scale enables a wide range of applications in biosensing, signal processing, and optoelectronics. A novel split-trench resonator platform combining resonant plasmonic biosensors and RF nanogap tweezers has been demonstrated, allowing for active sample concentration and label-free detection of analytes. This manufacturing method shows promise for practical applications in biosensing, spectroscopy, and optoelectronics.
Article
Chemistry, Physical
Debadi Chakraborty, Brian Uthe, Edward W. Malachosky, Matthew Pelton, John E. Sader
Summary: This study observed slip enhancement between flowing liquids and solid surfaces, caused by the intrinsic viscoelasticity of the liquid. The enhancement of slip compared to traditional models has implications on the understanding of ultrafast liquid flows and various technologies utilizing liquid flows.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Brian Uthe, Jesse F. Collis, Mahyar Madadi, John E. Sader, Matthew Pelton
Summary: The study successfully considered the compression and shear relaxation properties of the liquid using highly spherical gold nanoparticles to drive flows without the use of the no-slip boundary condition at the particle surface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Igor Fedin, Mateusz Goryca, Dan Liu, Sergei Tretiak, Victor Klimov, Scott A. Crooker
Summary: Studies have shown that colloidal CdSe quantum dots with a high degree of asymmetric internal strain exhibit desirable optical properties and have the potential for emitting single indistinguishable photons.
Article
Chemistry, Physical
Rachel M. Morin, Garnett W. Bryant, Elena Shevchenko, Yuchen Sha, Matthew Pelton
Summary: Characterizing the distribution of electron transfer rates from nanorods to molecules through individual measurements on CdSe/CdS core/shell nanorods functionalized with single methyl viologen molecules revealed that charge transfer most likely involves hot electrons in an excited conduction-band state. The ability to extract hot electrons from semiconductor nanocrystals may aid in energy-efficient photocatalysis, and the single-particle charge-transfer method could be a widely applicable tool to explore the spatial distribution of electronic states in nanocrystals.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Optics
Clement Livache, Whi Dong Kim, Ho Jin, Oleg Kozlov, Igor Fedin, Victor Klimov
Summary: Researchers have demonstrated that up-conversion in manganese-doped CdSe colloidal quantum dots enables efficient electron photoemission, leading to high-yield production of solvated electrons. This discovery has significant applications in visible-light-driven reduction photochemistry.
Article
Chemistry, Multidisciplinary
Aftab Ahmed, Rachel Gelfand, S. David Storm, Anna Lee, Anna Klinkova, Jeffrey R. Guest, Matthew Pelton
Summary: In this study, a low-frequency oscillating signal was observed in nanoparticles, indicating a nonlinear mixing process between a mechanical vibrational mode and an optical-frequency plasmon resonance.
Article
Multidisciplinary Sciences
Heeyoung Jung, Young-Shin Park, Namyoung Ahn, Jaehoon Lim, Igor Fedin, Clement Livache, Victor Klimov
Summary: This study addresses the challenges of fast optical-gain relaxation and poor stability in colloidal quantum dot (QD) solids, and achieves broad-band optical gain. By using continuously graded QDs and a current-focusing device design, combined with short-pulse pumping, ultra-high current densities and brightness are achieved, demonstrating an unusual two-band electroluminescence regime.
NATURE COMMUNICATIONS
(2022)
Review
Physics, Multidisciplinary
Brian Uthe, John E. Sader, Matthew Pelton
Summary: Standard continuum assumptions may not apply to fluid flows at the nanoscale, as even simple molecular liquids can exhibit non-Newtonian viscoelastic responses and nanometer-scale slip. Optical measurements of metal nanoparticles' mechanical vibrations provide insights into the rheology and slip behavior of simple liquids at the nanoscale.
REPORTS ON PROGRESS IN PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Jose J. Sanchez J. Rodriguez, Andrea N. Nunez N. Leon, Jabeen Abbasi, Pravin S. Shinde, Igor Fedin, Arunava Gupta
Summary: This study explores a new nanomaterial, CuCrS2, as a potential absorber layer in solar cells, due to its tunable physical and chemical properties. CuCrS2 nanosheets with average dimensions of 43.6 +/- 6.7 nm in length and 25.6 +/- 4.1 nm in width were synthesized and fabricated into films using the spray-coating method. The resulting film exhibited a net current conversion efficiency of approximately 11.3%.
Article
Biochemistry & Molecular Biology
Olaitan E. E. Oladipupo, Meredith C. C. Prescott, Emily R. R. Blevins, Jessica L. L. Gray, Colin G. G. Cameron, Fengrui Qu, Nicholas A. A. Ward, Abigail L. L. Pierce, Elizabeth R. R. Collinson, James Fletcher Hall, Seungjo Park, Yonghyun Kim, Sherri A. A. McFarland, Igor Fedin, Elizabeth T. T. Papish
Summary: This study investigated protic ruthenium complexes using the dihydroxybipyridine (dhbp) ligand combined with a spectator ligand (N,N = bpy, phen, dop, Bphen) for their potential activity against cancer cells and their photophysical luminescent properties. The complexes were studied in two protonation states, giving a total of 16 isolated complexes. Among them, complex 7(A) has been recently synthesized and characterized, and the deprotonated forms of three complexes are reported for the first time. Three light-activated complexes demonstrated photocytotoxicity and the log(D-o/w) values of the complexes were used to correlate with improved cellular uptake.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Physical
Sara Ansteatt, Brian Uthe, Bikash Mandal, Rachel S. S. Gelfand, Barry D. D. Dunietz, Matthew Pelton, Marcin Ptaszek
Summary: Strong excitonic coupling enables efficient light absorption and charge separation. Bioinspired BODIPY dyads with diethynylmaleimide linkers exhibit giant excitonic coupling and broad optical absorption. This discovery paves the way for the synthesis of molecular systems for efficient light-harvesting and solar energy conversion.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
