Article
Chemistry, Multidisciplinary
Elena Shornikova, Dmitri R. Yakovlev, Nikolay A. Gippius, Gang Qiang, Benoit Dubertret, Ali Hossain Khan, Alessio Di Giacomo, Iwan Moreels, Manfred Bayer
Summary: Colloidal semiconductor nanoplatelets exhibit strong quantum confinement for electrons and holes in one dimension, with significant increase in Coulomb interaction. The exciton binding energies are evaluated to be much higher compared to bulk CdSe, and comparable to monolayer-thick transition metal dichalcogenides.
Article
Optics
Alexander M. Smirnov, Anastasiya D. Golinskaya, Bedil M. Saidzhonov, Roman B. Vasiliev, Vladimir N. Mantsevich, Vladimir S. Dneprovskii
Summary: The dynamics of resonantly excited excitons in CdSe/CdS nanoplatelets are determined by exciton-exciton interaction and phonon-induced cascade relaxation. The study also reveals the significance of exciton-exciton interaction in exciton dynamics, particularly in relation to the saturation of heavy-hole and light-hole exciton transitions. Additionally, the study experimentally investigates the lowest four band structure of CdSe/CdS nanoplatelets and the bleaching of higher energy transitions due to rapid cascade relaxation of electrons and holes.
JOURNAL OF LUMINESCENCE
(2021)
Article
Materials Science, Multidisciplinary
Takeshi Koyama, Nobuki Umewaki, Kensuke Saito, Tomoki Tatsuno, Akira Fujisaki, Yasumitsu Miyata, Hiromichi Kataura, Hideo Kishida
Summary: This study investigates the photoluminescence (PL) properties of metallic single-walled carbon nanotubes. Steady-state measurements reveal interband excitonic PL in the first hyperbolic dispersion region, while femtosecond time-resolved measurements show the occurrence of intraband PL in the linear dispersion region. The decay time constant of interband excitonic PL is approximately 40 fs, while that of intraband PL is slower at lower photon energy. This study demonstrates the role of interband and intraband transitions in the PL of one-dimensional metals.
Article
Chemistry, Multidisciplinary
Davit A. Baghdasaryan, Volodya A. Harutyunyan, David B. Hayrapetyan, Eduard M. Kazaryan, Sotirios Baskoutas, Hayk A. Sarkisyan
Summary: This paper theoretically investigates the exciton states and their influence on the optical absorption spectrum of CdSe and PbS nanoplatelets. The problem is discussed in different size quantization regimes, and the corresponding potential that describes the electron-hole interaction in this mode of space quantization is chosen. The study reveals single-particle energy spectra, wave functions, and the dependence of material parameters on the number of monolayers in the sample. The effect of dielectric coefficient mismatch and different electron-hole interaction potentials are also studied.
Article
Chemistry, Multidisciplinary
Albert F. Vong, Shawn Irgen-Gioro, Yue Wu, Emily A. Weiss
Summary: Colloidal semiconductor nanoplatelets are scalable materials for optoelectronic applications and can be used for spin-to-photon transduction in quantum information networks. Negative trions are appealing emitters, but more preparation knowledge is needed to use them as single photon-emitting states. Through power-dependent time-resolved transient absorptions, it was shown that trions form via biexciton decay and not through collisional mechanisms typical for 2D materials.
Article
Nanoscience & Nanotechnology
Juan I. Climente, Bartlomiej Szafran
Summary: Calculations reveal that the photophysics of HgTe nanoplatelets are largely governed by the Gamma(6) - Gamma(8) band coupling, leading to a size-dependent energy spectrum and charge distribution. The thick HgTe NPLs with small band gap and large exciton binding energy suggest the potential for an excitonic insulator phase.
Article
Chemistry, Physical
Supriya Ghosh, Bach Pham, Meera Madhu, Bern Kohler
Summary: The transfer of hot electrons from plasmonic nanoparticles to metal oxide materials is achieved through core-shell nanoparticles and a hierarchical structure with reduced graphene oxide. This transfer increases the electron lifetime and enhances the photocatalytic performance, as demonstrated by the degradation of dye molecules.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Hongyu Yang, Lei Zhang, Wenbin Xiang, Changgui Lu, Yiping Cui, Jiayu Zhang
Summary: In this study, room-temperature exciton-polariton Bose-Einstein condensation was achieved and the realization of polariton laser was confirmed. Colloidal nanoplatelets show great prospects in low-cost, high-performance polariton devices and coherent light sources.
Article
Chemistry, Multidisciplinary
Sargis P. Gavalajyan, Grigor A. Mantashian, Gor Ts. Kharatyan, Hayk A. Sarkisyan, Paytsar A. Mantashyan, Sotirios Baskoutas, David B. Hayrapetyan
Summary: The exciton states in a conical GaAs quantum dot were studied using the effective mass approximation and the finite element method. The dependence of the exciton energy on the geometrical parameters of the dot was investigated. The exciton energy, effective band gap, lifetime, Raman scattering, interband light absorption, and photoluminescence spectra were calculated for different sizes of GaAs quantum dots.
Article
Nanoscience & Nanotechnology
Fatemeh Davoodi, Nahid Talebi
Summary: Van der Waals materials such as TMDCs exhibit strongly bound exciton states in the visible spectrum, providing an ideal platform for exciton-photon couplings. Utilizing nanometer-thick semiconducting TMDCs combined with metals can significantly increase light-matter interaction. In gold-WSe2 multilayers, both exciton A and exciton B can strongly interact with surface-plasmon polaritons, leading to CL emission suppression and revealing energy transfer between excitons and plasmons in the form of nonradiating guided waves.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Mher A. Mkrtchyan, David B. Hayrapetyan, Eduard M. Kazaryan, Hayk A. Sarkisyan, Maxim Ya. Vinnichenko, Vadim A. Shalygin, Dmitry A. Firsov, Lyudvig S. Petrosyan
Summary: This paper presents a theoretical investigation of interband and intraband transitions in an asymmetric biconvex lens-shaped quantum dot in the presence of an external magnetic field. Selection rules for intraband transitions are obtained and the behaviors of linear and nonlinear absorption and photoluminescence spectra are observed under different temperatures and magnetic field strengths. The study also examines the second and third harmonic generation coefficients as a function of photon energy in the absence and presence of an external magnetic field.
Article
Nanoscience & Nanotechnology
M. B. Yucel, S. Sakiroglu, H. Sari, C. A. Duque, E. Kasapoglu
Summary: This study theoretically investigates the ground-state binding energy and optical absorption coefficient of excitons in a symmetric double inverse parabolic quantum well system under external electric and magnetic fields. The results reveal that the exciton binding energy and interband optical absorption depend on the parameters defining the confinement potential, as well as the aluminum concentration, electric field, and magnetic field. The tunability of excitonic effects is expected to be crucial for the development of stable and efficient nanoscale excitonic optoelectronic devices.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Chemistry, Physical
Ivan D. Skurlov, Anastasiia Sokolova, Danila A. Tatarinov, Peter S. Parfenov, Danil A. Kurshanov, Azat O. Ismagilov, Aleksandra Koroleva, Denis Danilov, Evgeniy Zhizhin, Sergey Mikushev, Anton N. Tcypkin, Anatoly Fedorov, Aleksandr P. Litvin
Summary: The post-synthetic treatment of CsPbBr3 NPls with different Cd2+ sources was investigated, showing that the interplay between Cd2+ precursor, NPl concentrations, and ligands determines the kinetics of the doping process. Optimization of the treatment can boost the optical properties of NPls through doping and/or surface passivation.
Article
Optics
I. D. Laktaev, B. M. Saidzhonov, R. B. Vasiliev, A. M. Smirnov, O. V. Butov
Summary: The photoluminescence features of a light-hole - electron exciton transition in CdSe/CdS nanoplatelets colloidal solution under resonant two-photon excitation were investigated. The powerlaw dependence of the photoluminescence intensity on the excitation laser femtosecond pulses intensity was discovered to be related to biexciton radiation. In addition, the conditions for the photoluminescence growth and quenching were determined based on the concentration and pump intensity.
JOURNAL OF LUMINESCENCE
(2022)
Article
Chemistry, Multidisciplinary
Grigor A. Mantashian, Paytsar A. Mantashyan, Hayk A. Sarkisyan, Eduard M. Kazaryan, Gabriel Bester, Sotirios Baskoutas, David B. Hayrapetyan
Summary: This study theoretically investigates exciton-related Raman scattering, interband absorption, and photoluminescence in colloidal CdSe/CdS core/shell quantum dots ensemble using numerical discretization method within the effective-mass approximation. The interband optical absorption and photoluminescence spectra for CdSe/CdS quantum dots are revealed, taking into account the size dispersion of the ensemble. Numerical calculation of the differential cross section for exciton-related Stokes-Raman scattering in CdSe/CdS quantum dots ensemble with different mean sizes is presented.
Article
Chemistry, Physical
Sofia Masi, Carlos Echeverria-Arrondo, K. M. Muhammed Salim, Tuyen Thi Ngo, P. F. Mendez, Eduardo Lopez-Fraguas, David F. Macias-Pinilla, Josep Planelles, Juan Climente, Ivan Mora-Sero
ACS ENERGY LETTERS
(2020)
Article
Chemistry, Physical
David F. Macias-Pinilla, Carlos Echeverria-Arrondo, Andres Fabian Gualdron Reyes, Said Agouram, Vicente Munoz-Sanjose, Josep Planelles, Ivan Mora-Sero, Juan Climente
Summary: Research shows that colloidal PbS NPLs may have an orthorhombic crystal structure instead of the rock-salt structure found in bulk materials. Calculations indicate that quantum confinement along the a crystallographic axis strengthens the indirect band gap, while confinement along the b and c axes favors a direct band gap.
CHEMISTRY OF MATERIALS
(2021)
Article
Computer Science, Interdisciplinary Applications
Josep Planelles, Juan Climente
Summary: The computational model presented in this study, based on the variational Quantum Monte Carlo method and effective mass Hamiltonians, offers fast and accurate estimates of confinement and Coulomb binding energies. Through an iterative process and optional parallelization, calculations can be performed on standard desktop computers and achieve good agreement with exact calculations.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Chemistry, Physical
David F. Macias-Pinilla, Josep Planelles, Ivan Mora-Sero, Juan Climente
Summary: This study investigates the optoelectronic properties of metal chalcogenide colloidal nanoplatelets, revealing the presence of trion states in addition to excitonic states. The analysis shows how the additional charge in trions modifies emission energy and oscillator strength compared to neutral excitons, with properties sensitive to dielectric confinement and electronic correlations. Experimental and theoretical results are consistent, further evaluating the validity of previous theoretical approximations.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Corentin Dabard, Josep Planelles, Hong Po, Eva Izquierdo, Lina Makke, Charlie Greboval, Nicolas Moghaddam, Adrien Khalili, Tung Huu Dang, Audrey Chu, Stefano Pierini, Claire Abadie, Mariarosa Cavallo, Erwan Bossavit, Xiang Zhen Xu, Philippe Hollander, Mathieu Silly, Emmanuel Lhuillier, Juan I. Climente, Sandrine Ithurria
Summary: An optimized procedure was proposed for the growth of alloyed HgSe1-xTex NPLs, resulting in bright photoluminescence. With well-defined structural properties, the electronic properties of these objects can now be studied. A combination of methods clarified the origin of the similarity in absorption spectra of NPLs.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Jordi Llusar, Juan Climente
Summary: The optoelectronic properties of charged CdSe/CdTe colloidal nanoplatelets have been studied, and it is found that the number of excess carriers can be used to modulate the band gap, oscillator strength, and binding energy, which is of great significance for the design and application of optoelectronic devices.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Condensed Matter
Jordi Llusar, Juan Climente
Summary: This article examines the induction of nontrivial spin and orbital symmetries in colloidal nanoplatelets (NPLs) through the application of out-of-plane magnetic fields. Two scenarios are presented, one involving two confined electrons within a platelet and the other involving type-II core/crown NPLs.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Jordi Llusar, Juan I. Climente
Summary: Colloidal semiconductor nanoplatelets exhibit excellent optical emission properties due to their quasi-2D structures and strong in-plane Coulomb interactions. The charging of nanoplatelets with interacting fermions leads to severe Coulomb repulsions, resulting in strong electronic correlations and exchange energies. These phenomena give rise to characteristic physical effects such as deviating shell filling spectra, large addition energies for deterministic control of the number of charges, and activation of paramagnetic electron spin configuration at cryogenic temperatures.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Ivo Tanghe, Jordi Llusar, Juan Climente, Alex Barker, Giuseppe Paterno, Francesco Scotognella, Anatolii Polovitsyn, Ali Hossain Khan, Zeger Hens, Dries Van Thourhout, Pieter Geiregat, Iwan Moreels
Summary: By using CdSe/CdS nanocrystals with closely spaced hole levels and sparse electron states, a continuous broadband gain spectrum can be achieved, which is significant for photonics applications.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Corentin Dabard, Victor Guilloux, Charlie Greboval, Hong Po, Lina Makke, Ningyuan Fu, Xiang Zhen Xu, Mathieu G. Silly, Gilles Patriarche, Emmanuel Lhuillier, Thierry Barisien, Juan Climente, Benjamin T. Diroll, Sandrine Ithurria
Summary: The authors report on a double-crowned 2D semiconductor nanoplatelets as light downconverters, providing both green and red emissions to achieve a wide gamut. The ratio of the two emissions can be tuned by the incident power, and dual-color, power tunable emission can be obtained through electrical excitation.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Huichen Zhang, Victor Guilloux, Erwan Bossavit, Ningyuan Fu, Corentin Dabard, Mariarosa Cavallo, Tung Huu Dang, Adrien Khalili, Claire Abadie, Rodolphe Alchaar, Charlie Greboval, Xiang Zhen Xu, James K. Utterback, Debora Pierucci, Sandrine Ithurria, Juan I. Climente, Thierry Barisien, Emmanuel Lhuillier
Summary: In this study, we designed light amplitude modulators based on nanocrystal-based light-emitting diodes operated under reverse bias, achieving strong photoluminescence modulations for visible and near-telecom wavelengths using low bias operations (< 3 V) compatible with conventional electronics. For a visible device, we demonstrated that the photoluminescence quenching is driven by the field-induced change of nonradiative decay rate, and that the role of the field is less involved than the particle charging. This work shows that a simple diode stack can combine multiple functionalities (light-emitting diode, detector, and light modulator) simply by selecting the driving bias.
Article
Computer Science, Interdisciplinary Applications
Jose L. Movilla, Juan I. Climente, Josep Planelles
Summary: The researchers provide expressions for the magnetic fields induced by the electrostatic charges near the interface between topological and ordinary insulators in a system with two planar-parallel interfaces. The formulae can be used to model magnetoelectric fields in topological quantum wells, thin films, or layers of two-dimensional materials.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Juan I. Climente, Bartlomiej Szafran
Summary: Calculations reveal that the photophysics of HgTe nanoplatelets are largely governed by the Gamma(6) - Gamma(8) band coupling, leading to a size-dependent energy spectrum and charge distribution. The thick HgTe NPLs with small band gap and large exciton binding energy suggest the potential for an excitonic insulator phase.
Article
Physics, Multidisciplinary
Josep Planelles, Jose L. Movilla, Juan I. Climente
Summary: Electrostatic charges placed near the interface between ordinary and topological insulators induce magnetic fields through the topological magnetoelectric effect. We present a numerical implementation of the associated Maxwell equations. The model is simple, fast, and accurate, and is used to study the influence of dimensions and shape on magnetoelectric fields in semiconductor nanostructures.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
David F. Macias-Pinilla, Josep Planelles, Juan Climente
Summary: The biexciton properties in semiconductor nanostructures are influenced by quantum confinement, electron-hole masses, dielectric environment, and Coulomb correlations. A variational Quantum Monte Carlo model coupled to effective mass Hamiltonians is used to analyze the biexciton ground state properties in colloidal CdSe nanoplatelets. The results show that the thickness of the nanoplatelets leads to a distorted tetrahedral shape of the biexciton, and the strong dielectric confinement affects both Coulomb attractions and repulsions. The ratio of biexciton-to-exciton binding energy is reduced, but the biexciton can still be stable at room temperature. The ratio of biexciton-to-exciton radiative rates decreases as the platelet area increases.