Article
Chemistry, Multidisciplinary
Wei Fu, Jiefu Yin, Huaqiang Cao, Zhongfu Zhou, Junying Zhang, Jingjing Fu, Jamie H. Warner, Cheng Wang, Xiaofang Jia, G. Neville Greaves, Anthony K. Cheetham
Summary: The photoluminescence blinking behavior of single quantum dots under steady illumination is a significant yet controversial topic. It hinders the use of single quantum dots in bioimaging. Different mechanisms, particularly the non-radiative Auger recombination mechanism, have been proposed to explain it. Fluorescence non-blinking is observed in photocharged single graphene quantum dots (GQDs) due to the presence of singly charged trions that maintain photon emission through radiative and non-radiative Auger recombination. This phenomenon is attributed to the different energy levels caused by oxygen-containing functional groups in the GQDs, and the suppression of blinking is attributed to trap site filling caused by Coulomb blockade.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
C. A. Sgroi, J. Brault, J. -Y. Duboz, S. Chenot, P. Vennegues, A. Ludwig, A. D. Wieck
Summary: We present capacitance-voltage measurements of self-assembled wurtzite-GaN quantum dots (QDs). The QDs are embedded in a charge-tunable diode structure and were grown by molecular beam epitaxy using the Stranski-Krastanov growth method. The study shows that charges and the internal electric fields influence the energy spacing in the QDs and demonstrates the possibility of achieving single-electron charging and Coulomb blockade energy in the QDs at room temperature.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Omar E. Solis, Jesus Manuel Rivas, Angel A. Duran-Ledezma, Alejandro Gonzalez-Cisneros, Miguel Garcia-Rocha, Diego Esparza
Summary: Increasing the iodine content in cesium lead bromide-iodide quantum dots can increase defect concentration, leading to an increase in non-radiative recombination processes. These PQDs exhibit high light absorption and photoluminescence, absorbing light in the range of 500 to 550 nm and showing multiple peaks in the photoluminescence spectra.
Article
Chemistry, Multidisciplinary
Xiaolei Chu, Alex Abelson, Caroline Qian, Oleg Igouchkine, Ethan Field, Kwan-Liu Ma, Matt Law, Adam J. J. Moule
Summary: Using scanning transmission electron microscopy (STEM) and full-tilt tomographic reconstruction, a single-crystalline region of a 3D epitaxially-fused PbSe quantum dot (QD) superlattice containing 633 QDs was imaged at a spatial resolution of 2.16 angstrom. The analysis revealed 3D mesoscale correlations of atomic lattice and superlattice order across hundreds of nanocrystals, and showed that the QD surface layers template the superlattice. The techniques presented in this study can be applied to a wide range of 3D nanostructured materials.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Biochemistry & Molecular Biology
Ying Pan, Lulu Xue, Yinjie Chen, Yingjie Hu, Zhicheng Sun, Lixin Mo, Luhai Li, Haifeng Yu
Summary: A simple approach for fabricating luminous self-assembled fibers using halogen-bonded azopyridine complexes and oleic acid-modified quantum dots is reported. The method allows for retention of the fluorescence properties of the quantum dots in the fibers, which can also be assembled into tailored directional fibers through solvent evaporation.
Article
Quantum Science & Technology
Qin Wan, Fei Zeng, Junwei Yu, Tongjin Chen, Ziao Lu, Feng Pan
Summary: Research and development of memristor-based neuromorphic networks has reached large-scale application stage, but a thorough understanding of the adopted memristors is still lacking. In this study, a method to manipulate the local activity of NbO quantum dot (QD) system by creating an electrode tip is proposed, enabling reversible nucleation behavior and periodic pulsing. These mechanisms contribute to the information-energy conversion in the QD system and provide a more precise and low energy-consumption approach for neuromorphic computing.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Chemistry, Multidisciplinary
Anton A. Babaev, Anastasiia Sokolova, Sergei A. Cherevkov, Kevin Berwick, Alexander Baranov, Anatoly Fedorov, Aleksandr P. Litvin
Summary: This study proposes a model based on Auger recombination and energy transfer to explain the dependence of average PL lifetime on the component ratio in the rGO/QD system. Additional experiments and mathematical simulation support the role of excess holes in the QDs and the importance of energy transfer between neighboring QDs in quenching the PL.
Article
Multidisciplinary Sciences
Jisu Ryu, Samuel D. Park, Dmitry Baranov, Iva Rreza, Jonathan S. Owen, David M. Jonas
Summary: Femtosecond two-dimensional (2D) spectroscopy is used to separate size dispersion broadening in quantum-confined nanomaterials, allowing determination of thermodynamic differences and maximum photovoltage. The study shows how single-molecule generalized Einstein relations can be applied to average single-molecule linewidth and determine key parameters between absorption and emission spectra.
Article
Chemistry, Multidisciplinary
Mona Atabakhshi-Kashi, Monica Carril, Hossein Mahdavi, Wolfgang J. Parak, Carolina Carrillo-Carrion, Khosro Khajeh
Summary: The successful conjugation of antibodies onto a fluorescent NP assembly demonstrated that the NP assembly retained the targeting ability of the antibodies in cellular uptake, while also preserving its intrinsic properties such as fluorescence.
Article
Chemistry, Multidisciplinary
Chao-Rui Li, Yu-Li Lei, Hua Li, Miao Ni, Dong-Rui Yang, Xiao-Yu Xie, Yuan-Fan Wang, Hai-Bo Ma, Wei-Gao Xu, Xing-Hua Xia
Summary: Fluorescence efficiency of molybdenum disulfide quantum dots can be enhanced by single-atom metal modification, which improves their economic efficiency and stability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Nanoscience & Nanotechnology
YuJin Lee, Dae-Yeon Jo, Taehee Kim, Jung-Ho Jo, Jumi Park, Heesun Yang, Dongho Kim
Summary: This study investigates the effects of shell structure and composition on photoluminescence properties of quantum dots. It discovers that gradient shells can effectively suppress nonradiative Auger recombination and improve the luminescence of the dots. Single-dot measurements show that gradient shells reduce spectral diffusion and enhance the energy barrier for charge trapping.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Zhijing Zhang, Sushant Ghimire, Takuya Okamoto, Bhagyashree Mahesha Sachith, Jeladhara Sobhanan, Challapalli Subrahmanyam, Vasudevanpillai Biju
Summary: This study reports the mechanically changing excitons and photoluminescence of self-assembled formamidinium lead bromide (FAPbBr(3)) quantum dots. The structure and excitonic properties of individual quantum dots are different from the self-assemblies. The mechanically changing emission color and lifetime of halide perovskite have potential applications in mechano-optical and optomechanical devices.
Article
Chemistry, Multidisciplinary
Maarten Stam, Indy du Fosse, Ivan Infante, Arjan J. Houtepen
Summary: This study provides theoretical insight into the effect of electron charging on InP QDs and proposes a method to avoid trap state formation during the charging process.
Article
Materials Science, Multidisciplinary
Olha Aftenieva, Markas Sudzius, Anatol Prudnikau, Mohammad Adnan, Swagato Sarkar, Vladimir Lesnyak, Karl Leo, Andreas Fery, Tobias A. F. Koenig
Summary: Miniaturized laser sources with low threshold power can be achieved by using photostable core/shell nanocrystals as gain material and directly patterning them as distributed feedback (DFB) lasers. The subwavelength pattern resolution required for DFB lasers is achieved through soft lithography based on template-assisted colloidal self-assembly. The combination with the directional Langmuir-Blodgett arrangement allows for control of the waveguide layer thickness.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Physics, Condensed Matter
Bashdar Rahman Pirot, Nzar Rauf Abdullah, Andrei Manolescu, Vidar Gudmundsson
Summary: We study thermoelectric transport through a serial double quantum dot coupled to two metallic leads with different thermal energies. Coulomb interactions and coherent effects are found to have significant impacts on the transport properties, leading to extra transport channels and enhanced thermoelectric effects.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Multidisciplinary Sciences
Andrew B. Matheson, Lynn Paterson, Amanda J. Wright, Tania Mendonca, Manlio Tassieri, Paul A. Dalgarno
Summary: The novel 3D microrheology system OpTIMuM integrates Optical Tweezers with Integrated Multiplane Microscopy for the first time, allowing the precise tracking of optically trapped beads with around 20 nm accuracy along the optical axis. This system does not require a high precision z-stage or separate calibration sample, and features a simple yet effective in situ spatial calibration method using image sharpness. We demonstrated its effectiveness by measuring the viscosity of water in three dimensions simultaneously.
SCIENTIFIC REPORTS
(2021)
Article
Biochemistry & Molecular Biology
Patrick St-Pierre, Euan Shaw, Samuel Jacques, Paul A. Dalgarno, Cibran Perez-Gonzalez, Frederic Picard-Jean, J. Carlos Penedo, Daniel A. Lafontaine
Summary: Experimental evidence reveals the presence of a structural intermediate in the folding pathway of the adenine riboswitch, which acts as an open conformation to ensure ligand accessibility and eventually folds into a structure nearly identical to the ligand-bound complex. This study demonstrates that the adenine riboswitch relies on the folding of a structural intermediate to facilitate efficient metabolite sensing and genetic regulation.
NUCLEIC ACIDS RESEARCH
(2021)
Article
Physics, Multidisciplinary
Andrew B. Matheson, Tania Mendonca, Graham M. Gibson, Paul A. Dalgarno, Amanda J. Wright, Lynn Paterson, Manlio Tassieri
Summary: This study investigated the effect of anisotropic optical traps on microrheology measurements and found that using highly anisotropic optical traps for viscosity measurements will lead to erroneous results. It introduced a new analytical approach for anisotropic traps with two axes of symmetry and identified a threshold level of anisotropy in optical trap strength. The outcomes of this study may have important practical ramifications on how all microrheology measurements should be conducted and analyzed in the future.
FRONTIERS IN PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Hyeonjun Baek, Mauro Brotons-Gisbert, Aidan Campbell, Valerio Vitale, Johannes Lischner, Kenji Watanabe, Takashi Taniguchi, Brian D. Gerardot
Summary: Trapped excitons in a molybdenum diselenide/tungsten diselenide heterobilayer device can serve as a sensitive optical probe for carrier filling. By mapping the spatial positions of individual trapped excitons, it is possible to spectrally track the emitters as the moire lattice is filled with excess carriers, providing insights into Coulomb interaction energies and visualizing charge correlated states.
NATURE NANOTECHNOLOGY
(2021)
Article
Multidisciplinary Sciences
Zhe Xian Koong, Moritz Cygorek, Eleanor Scerri, Ted S. Santana, Suk In Park, Jin Dong Song, Erik M. Gauger, Brian D. Gerardot
Summary: This study explores the coherence effect on cooperative emission between two distant but indistinguishable solid-state emitters through path erasure. The experimental results show that the photon statistics from a pair of indistinguishable emitters resemble that of a weak coherent state from an attenuated laser, in contrast to uncorrelated emitters. These experiments establish techniques to control and characterize cooperative behavior between matter qubits using the full quantum optics toolbox, a key step toward realizing large-scale quantum photonic networks.
Article
Multidisciplinary Sciences
M. G. R. Guastamacchia, R. Xue, K. Madi, W. T. E. Pitkeathly, P. D. Lee, S. E. D. Webb, S. H. Cartmell, P. A. Dalgarno
Summary: Multifocal microscopy (MUM) is a promising technique that can capture multiple fields of view from distinct axial planes simultaneously for micro-particle image velocimetry (mu PIV) with high accuracy. MUM can be applied to both fixed cells and live cells, showing significant advantages in speed of acquisition for mu PIV compared to standard confocal laser scanning microscope.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Imogen Morland, Feng Zhu, Paul Dalgarno, Jonathan Leach
Summary: This study presents a technique for measuring target depth using non-linear optical methods with high precision on very small length scales. By utilizing statistical estimation theory and sCMOS camera data, it achieves approximately 30 nm depth precision for each pixel in 30 seconds.
Article
Nanoscience & Nanotechnology
Aidan J. Campbell, Mauro Brotons-Gisbert, Hyeonjun Baek, Valerio Vitale, Takashi Taniguchi, Kenji Watanabe, Johannes Lischner, Brian D. Gerardot
Summary: This study investigates the behavior of exciton-polarons in strongly correlated electronic states and reveals the rich potential of the MoSe2/WSe2 platform.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Physics, Applied
Christiaan Bekker, Muhammad Junaid Arshad, Pasquale Cilibrizzi, Charalampos Nikolatos, Peter Lomax, Graham S. Wood, Rebecca Cheung, Wolfgang Knolle, Neil Ross, Brian Gerardot, Cristian Bonato
Summary: Grayscale lithography is used to create micrometer-scale features with controlled height in a compatible process with standard lithography. A fabrication protocol combining grayscale lithography and hard-mask techniques enables the creation of nearly hemispherical solid immersion lenses in silicon carbide substrate. The lens performance is evaluated by studying the enhancement in optical collection efficiency for single quantum emitters, showing a reproducible alternative to focused ion beam milling for high-aspect-ratio, rounded microstructures in quantum technology and microphotonic applications.
APPLIED PHYSICS LETTERS
(2023)
Editorial Material
Chemistry, Physical
Mauro Brotons-Gisbert, Brian D. Gerardot
Summary: An optical spectroscopy approach is used to reveal different layer-dependent correlated electron phases in a two-dimensional semiconductor heterobilayer.
Article
Multidisciplinary Sciences
Christopher L. Morrison, Roberto G. Pousa, Francesco Graffitti, Zhe Xian Koong, Peter Barrow, Nick G. Stoltz, Dirk Bouwmeester, John Jeffers, Daniel K. L. Oi, Brian D. Gerardot, Alessandro Fedrizzi
Summary: This paper presents a scheme for quantum key distribution using solid-state single-photon emitters. By frequency converting single photons generated by quantum dots to 1550 nm, count rates of 1.6 MHz and positive key rates over 175 km of telecom fibre are achieved. The researchers use a tighter multiplicative Chernoff bound to constrain estimated finite key parameters, significantly reducing the required number of received signals.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
M. Kogl, P. Soubelet, M. Brotons-Gisbert, A. V. Stier, B. D. Gerardot, J. J. Finley
Summary: Large-scale two-dimensional (2D) moire superlattices are revolutionizing the field of designer quantum materials. By utilizing strain, we have developed a method to modify the periodicity and symmetry of the moire lattice in situ. This allows for fine-tuning of the lattice near critical points and complete reconfiguration of the lattice symmetry. The ability to control both electronic interactions and lattice symmetry simultaneously makes 2D heterostrain a powerful platform for engineering and studying strongly correlated moire materials.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Biology
Tania Mendonca, Katarzyna Lis-Slimak, Andrew B. Matheson, Matthew G. Smith, Akosua B. Anane-Adjei, Jennifer C. Ashworth, Robert Cavanagh, Lynn Paterson, Paul A. Dalgarno, Cameron Alexander, Manlio Tassieri, Catherine L. R. Merry, Amanda J. Wright
Summary: OptoRheo, a new instrument combining light sheet fluorescence microscopy and particle tracking microrheology, allows for live imaging and micromechanical sensing of extracellular matrix-cell interactions. By developing OptoRheo, we can image cells in 3D while simultaneously sensing the mechanical properties of the surrounding extracellular and pericellular matrix at a sub-cellular length scale. OptoRheo can be operated in two modes (with and without an optical trap) to extend the dynamic range of microrheology measurements. We validated this by characterizing the extracellular matrix surrounding live breast cancer cells in two different culture systems.
COMMUNICATIONS BIOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Lukas Sigl, Mirco Troue, Manuel Katzer, Malte Selig, Florian Sigger, Jonas Kiemle, Mauro Brotons-Gisbert, Kenji Watanabe, Takashi Taniguchi, Brian D. Gerardot, Andreas Knorr, Ursula Wurstbauer, Alexander W. Holleitner
Summary: In this study, we investigate the photoluminescence intensity distribution of interlayer excitons in MoSe2-WSe2 heterostacks using back focal plane imaging. By comparing the data with an analytical model, we determine the relative contributions of in-plane and out-of-plane transition dipole moments associated with interlayer exciton photon emission. The results show that the in-plane transition dipole moments dominate in all observed interlayer exciton transitions.
Review
Physics, Applied
Mikko Turunen, Mauro Brotons-Gisbert, Yunyun Dai, Yadong Wang, Eleanor Scerri, Cristian Bonato, Klaus D. Jons, Zhipei Sun, Brian D. Gerardot
Summary: Quantum photonics based on 2D materials offers an integrated and scalable approach to quantum information processing and communication. This article summarizes the current state, fundamental properties, and challenges of coherent quantum photonic devices using 2D layered materials. It also provides an outlook on future prospects in this rapidly advancing field.
NATURE REVIEWS PHYSICS
(2022)