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Light-driven anisotropy of 2D metal-organic framework single crystal for repeatable optical modulation
Structural transformations offer a route to control functional properties but it is difficult to design metal-organic frameworks with multiple and fast transformations. Here, a 2D metal-organic framework was designed with continuous structural transformations driven by light and used for optical modulation.
- Yuliya A. Kenzhebayeva
- , Nikita K. Kulachenkov
- & Valentin A. Milichko
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| Open Access
Activation of telecom emitters in silicon upon ion implantation and ns pulsed laser annealing
Defected silicon has uses in optically active telecom emitters. Here, nanosecond pulsed laser annealing is demonstrated as a non-invasive, localized method to activate the defects in high-purity silicon substrates.
- Greta Andrini
- , Gabriele Zanelli
- & Jacopo Forneris
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| Open Access
History-dependent nano-photoisomerization by optical near-field in photochromic single crystals
Memory structures are key components of any functional computing device, but achieving persistent storage of information in the form of light is extremely difficult. Here, the authors demonstrate the sequential formation of multiple memory pathways in photochromic crystals via optical near-field interactions.
- Yuji Arakawa
- , Kazuharu Uchiyama
- & Hirokazu Hori
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| Open Access
Deeply subwavelength mid-infrared phase retardation with α-MoO3 flakes
Polarization rotation is key for modern optics but achieving it at mid-infrared frequencies is challenging and requires very thick phase retarders. Here, α-MoO3 flakes provide mid-infrared phase retardation and 90 degrees polarization rotation within one micrometer of material, a thickness ten times thinner than the operational wavelength.
- Michael T. Enders
- , Mitradeep Sarkar
- & Georgia T. Papadakis
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| Open Access
Enhanced luminescence efficiency in Eu-doped GaN superlattice structures revealed by terahertz emission spectroscopy
A superlattice structure in Eu-doped GaN is known to improve the power output of red LEDs, though the mechanism behind this needs to be further established. Here, terahertz emission spectroscopy is used to understand the role played by potential barriers and carrier confinement in determining power output.
- Fumikazu Murakami
- , Atsushi Takeo
- & Masayoshi Tonouchi
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| Open Access
Band gap predictions of double perovskite oxides using machine learning
Tuning the band gap of perovskite oxides is key for achieving tailored electronic properties in transistors, LEDs, photovoltaics, and scintillators. Here, by exploring all chemical combinations of 68 elements, machine learning is used to identify and predict stable synthesizable cubic perovskites with desired band gap values.
- Anjana Talapatra
- , Blas Pedro Uberuaga
- & Ghanshyam Pilania
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| Open Access
Structural and optical properties of gold nanosponges revealed via 3D nano-reconstruction and phase-field models
Accurate predictions of nanosponge properties are challenging as it requires detailed knowledge of their chaotic structure. Here, a procedure for their accurate 3D reconstruction is presented using focused ion beam tomography with simulations to create models with adjustable geometric properties.
- Malte Grunert
- , Sebastian Bohm
- & Peter Schaaf
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Article
| Open Access
Dynamic spatio-temporal control of naturally sourced soft photonic crystals
Controlling the dynamics of natural soft photonic systems is challenging due to difficulties in sourcing and stimulating them. Here, natural bovine tapetum is used to investigate soft biophotonic crystals and dynamically control their response, providing insight into the development of displays and dynamic light management.
- Giulia Guidetti
- , Chris Pirie
- & Fiorenzo G. Omenetto
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Triplet sensitization via charge recombination at organic heterojunction for efficient near-infrared to visible solid-state photon upconversion
A near-infrared to visible photon upconversion device was previously shown to increase external quantum efficiency by up to 2.3%. Here, the upconversion mechanism is studied by time-resolved spectroscopy, revealing that 67% of incident photons are utilized.
- Yuji Sakamoto
- , Seiichiro Izawa
- & Yasunari Tamai
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| Open Access
Doped semiconducting polymer nanoantennas for tunable organic plasmonics
Optical nanoantennas based on organic plasmonics are promising for their higher degree of tunability over metallic nanostructures. Here, nanodisks of polythiophene-based semiconducting polymers provide nanooptical antennas with resonances that are tunable over a 1000 nm wavelength range and can be switched off or on by doping modulation.
- Akchheta Karki
- , Yu Yamashita
- & Magnus P. Jonsson
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Controlling triplet–triplet upconversion and singlet-triplet annihilation in organic light-emitting diodes for injection lasing
Losses induced by triplet excitons are a major obstacle for electrically pumped organic lasers. Here, a combination of enhanced triplet-triplet upconversion and suppressed singlet-triplet annihilation is demonstrated as a route towards lasing in organic light emitting diodes.
- Atul Shukla
- , Monirul Hasan
- & Ebinazar B. Namdas
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Article
| Open Access
Growth of α-Sn on silicon by a reversed β-Sn to α-Sn phase transformation for quantum material integration
α-Sn and SnGe alloys are a promising new class of quantum materials, but device integration requires they be grown on silicon. Here, germanium-doped α-Sn is grown on a native oxide on a silicon substrate via a reversed β-Sn to α-Sn phase transformation.
- Shang Liu
- , Alejandra Cuervo Covian
- & Jifeng Liu
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Organic photostimulated luminescence associated with persistent spin-correlated radical pairs
Materials that display photostimulated luminescence are attractive for multiple applications. Here, photostimulated luminescence is demonstrated in an all-organic blend film, in which a dopant molecule functions as both an electron trap and a light emitter.
- Manabu Sakurai
- , Ryota Kabe
- & Takashi Tachikawa
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Effect of chemically induced permittivity changes on the plasmonic properties of metal nanoparticles
Studying the bonding of organic molecules onto the surface of metal nanomaterials is important for understanding their plasmonic properties. Here, changes in the electron density of states at the metal-ligand interface of Ag nanoparticles are linked to variations in localized dipole moments and interface permittivity.
- Noboru Saito
- , Sou Ryuzaki
- & Kaoru Tamada
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| Open Access
Out-of-plane trion emission in monolayer WSe2 revealed by whispering gallery modes of dielectric microresonators
Out-of-plane photon emission in 2D semiconductors is rare but crucial for efficient light manipulation in planar optoelectronic devices and photonic chips. Here, an out-of-plane dipolar component of trions in monolayer WSe2 is revealed by exciting the whispering gallery modes of SiO2 microspherical resonators.
- Daniel Andres-Penares
- , Mojtaba Karimi Habil
- & Juan F. Sánchez-Royo
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Electro-absorption modulation in GeSn alloys for wide-spectrum mid-infrared applications
Silicon-based electronic-photonic integrated circuits are promising for various applications, but their mid-infrared optical modulation is elusive. Here, tunable mid-infrared electro-absorption modulation, with broadband operation range >140 nm, is achieved in GeSn alloys on Si by controlling the Sn content.
- Yun-Da Hsieh
- , Jun-Han Lin
- & Guo-En Chang
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| Open Access
Interrogating helical nanorod self-assembly with fractionated cellulose nanocrystal suspensions
Aligning cholesteric liquid crystal nanorods is key to their optical properties, yet challenging to achieve in artificial systems. Here cellulose nanorods are fractionated from suspension, revealing that nanorod length correlates with helical twist, allowing uniformly violet films to be created.
- Camila Honorato-Rios
- & Jan P. F. Lagerwall
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| Open Access
Lithium-doped two-dimensional perovskite scintillator for wide-range radiation detection
Two-dimensional lead halide perovskites have shown great potential as X- and γ-ray scintillators due to their high light yield, fast decay rate, and low fabrication cost. Here, their versatility is expanded by achieving, via Li-doping, α-particle/γ-ray discrimination and thermal neutron detection.
- Aozhen Xie
- , Chathuranga Hettiarachchi
- & Cuong Dang
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| Open Access
Imaging shape and strain in nanoscale engineered semiconductors for photonics by coherent x-ray diffraction
Coherent x-ray diffractive imaging is a powerful technique for determining strain on the nanometer scale. Here, it is used to image semiconducting GaAs1-yNy structures on a GaAs substrate and to measure strain, demonstrating its potential for studying highly strained interfaces in devices.
- Felisa Berenguer
- , Giorgio Pettinari
- & Gianluca Ciatto
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| Open Access
Signatures of complex optical response in Casimir interactions of type I and II Weyl semimetals
The ubiquitous Casimir interaction arises from electromagnetic fluctuations exchanged between objects. Here, by determining the optical conductivity components for type I and II Weyl semimetals, it is found that the Casimir interaction has strong similarities to metals, while the nontrivial topology plays a secondary role.
- Pablo Rodriguez-Lopez
- , Adrian Popescu
- & Lilia M. Woods
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| Open Access
Active spatial control of terahertz plasmons in graphene
Controlling spatial conductivity in graphene is important for plasmonic devices, yet conductivity patterning typically changes the electromagnetic environment. Here, teraherz plasmons in graphene are confined to specific regions via a patterned zinc oxide gate, reducing electromagnetic coupling.
- Ngoc Han Tu
- , Katsumasa Yoshioka
- & Norio Kumada
Superlattice assembly strategy of small noble metal nanoparticles for surface-enhanced Raman scattering