Full Spectrum Of Visible Light Research Articles

Multifunction fluorescence open source in vivo/in vitro imaging system (openIVIS).

The widespread availability and diversity of open-source microcontrollers paired with off-the-shelf electronics and 3D printed technology has led to the creation of a wide range of low-cost scientific instruments, including microscopes, spectrometers, sensors, data loggers, and other tools that can be used for research, education, and experimentation. These devices can be used to explore a wide range of scientific topics, from biology and chemistry to physics and engineering. In this study, we designed and built a multifunction fluorescent open source in vivo/in vitro imaging system (openIVIS) system that integrates a Raspberry Pi with commercial cameras and LEDs with 3D printed structures combined with an acrylic housing. Our openIVIS provides three excitation wavelengths of 460 nm, 520 nm, and 630 nm integrated with Python control software to enable fluorescent measurements across the full visible light spectrum. To demonstrate the potential applications of our system, we tested its performance against a diverse set of experiments including laboratory assays (measuring fluorescent dyes, using optical nanosensors, and DNA gel electrophoresis) to potentially fieldable applications (plant and mineral imaging). We also tested the potential use for a high school biology environment by imaging small animals and tracking their development over the course of ten days. Our system demonstrated its ability to measure a wide dynamic range fluorescent response from millimolar to picomolar concentrations in the same sample while measuring responses across visible wavelengths. These results demonstrate the power and flexibility of open-source hardware and software and how it can be integrated with customizable manufacturing to create low-cost scientific instruments with a wide range of applications. Our study provides a promising model for the development of low-cost instruments that can be used in both research and education.

Biochemical and molecular characterization of the SBiP1 chaperone from Symbiodinium microadriaticum CassKB8 and light parameters that modulate its phosphorylation.

The coding and promoter region sequences from the BiP-like protein SBiP1 from Symbiodinium microadriaticum CassKB8 were obtained by PCR, sequenced and compared with annotated sequences. The nucleotides corresponding to the full sequence were correctly annotated and the main SBiP1 features determined at the nucleotide and amino acid level. The translated protein was organized into the typical domains of the BiP/HSP70 family including a signal peptide, a substrate- and a nucleotide-binding domain, and an ER localization sequence. Conserved motifs included a highly conserved Thr513 phosphorylation site and two ADP-ribosylation sites from eukaryotic BiP's. Molecular modeling showed the corresponding domain regions and main exposed post-translational target sites in its three-dimensional structure, which also closely matched Homo sapiens BiP further indicating that it indeed corresponds to a BiP/HSP70 family protein. The gene promoter region showed at least eight light regulation-related sequences consistent with the molecule being highly phosphorylated in Thr under dark conditions and dephosphorylated upon light stimuli. We tested light parameter variations that could modulate the light mediated phosphorylation effect and found that SBiP1 Thr dephosphorylation was only significantly detected after 15-30 min light stimulation. Such light-induced dephosphorylation was observed even when dichlorophenyl dimethyl urea, a photosynthesis inhibitor, was also present in the cells during the light stimulation. Dephosphorylation occurred indistinctly under red, yellow, blue or the full visible light spectra. In additon, it was observed at a light intensity of as low as 1 μmole photon m-2 s-1. Our results indicate that: a) SBiP1 is a chaperone belonging to the BiP/HSP70 family proteins; b) its light-modulated phosphorylation/dephosphorylation most likely functions as an activity switch for the chaperone; c) this light-induced modulation occurs relatively slow but is highly sensitive to the full spectrum of visible light; and d) the light induced Thr dephosphorylation is independent of photosynthetic activity in these cells.

Bio-Inspired Hydrogel-Elastomer Actuator with Bidirectional Bending and Dynamic Structural Color.

In nature, some creatures can change their body shapes and surface colors simultaneously to respond to the external environments, which greatly inspired researchers in the development of color-tunable soft actuators. In this work, we present a facile method to prepare a smart hydrogel actuator that can bend bidirectionally and change color simultaneously, just like an octopus. The actuator is fabricated by elastomer/hydrogel bilayer and the hydrogel layer was decorated with thermoresponsive microgels as the photonic crystal blocks. Compared with the previously reported poly(N-isopropylacrylamide) hydrogel-based bilayer hydrogel actuators, which are generally limited to one-directional deformation, the elastomer/hydrogel bilayer actuator prepared in our work exhibits unique bidirectional bending behavior in accordance with the change of structural color. The bending degrees can be changed from -360° to 270° in response to solution temperatures ranging from 20 °C to 60 °C. At the same time, the surface color changes from red to green, and then to blue, covering the full visible light spectrum. The bending direction and degree of the hydrogel actuator can easily be adjusted by tuning the layer thickness ratio of the elastomer/hydrogel or the composition of the hydrogel. The color-tunable hydrogel-elastomer actuator reported in this work can achieve both programmable deformations and color-changing highly resembling the natural actuating behaviors of creatures.

Wet‐Chemical Etching and Delamination of MoAlB into MBene and Its Outstanding Photocatalytic Performance

AbstractMBenes are post‐MXene materials that contain boron in their structure instead of carbon and nitrogen. This unique composition offers an opportunity to explore the role of boron in the performance of 2D materials. However, wet‐chemical etching and delamination of the starting MoAlB phase are challenging due to the persistent bonding of aluminum atoms with their neighboring elements. Herein, it is overcome by processing MoAlB for 24, 48, and 72 h with an aqueous HCl/H2O2 solution. The time‐wise etching and delamination delivers individual single‐to‐few layered 48‐MBene flakes. The theoretical‐to‐experimental XRD analysis revealed the best‐delaminated 48‐MBene having Mo2B2 orthorhombic lattice arrangement. The presence of Mo oxide allows direct 1.2 eV and indirect 0.2 eV optical band gaps and outstanding photocatalytic activity in decomposing methylene blue as a model organic contaminant. The 48‐MBene photocatalyst achieves about 90% of MB decomposition under ultraviolet and simulated white light irradiation with three times faster kinetics outperforming even hybridized MXenes. In addition, 48‐MBene appeared best suited to utilize the full spectrum of visible light into reactive oxygen species. Conversely, 24‐MBene and 72‐MBene shows incomplete delamination or oxidation, hampering their photocatalytic activity. The obtained results open an experimental pathway to apply MBenes in environmental remediation.

Cobalt quantum dots as electron collectors in ultra-narrow bandgap dioxin linked covalent organic frameworks for boosting photocatalytic solar-to-fuel conversion

Photocatalysis offers a sustainable paradigm for solar-to-fuel conversion because it conflates the merits of renewable solar energy and reusable catalysts. However, the seek for robust photocatalysts that can utilize the full visible light spectrum remains challenging. Herein, cobalt quantum dots (Co QDs) were integrated into ultra-narrow bandgap dioxin linked covalent organic frameworks (COF-318) for photocatalytic solar-to-fuel conversion under full spectrum of visible light irradiation. The optimal Co10-COF exhibited superior photocatalytic CO2 reduction performance, affording a CO yield of 4232 µmol∙g−1∙h−1 and H2 evolution of 6611 µmol∙g−1∙h−1. Specifically, Co QDs played a crucial role in boosting the photocatalytic performance, which acted as electron collectors to capture the photoinduced electrons and then conveyed them to CO2 molecules. Moreover, the Co QDs modification significantly improved the CO2 adsorption and activation capacity, as well as prolonging the lifetime of photogenerated carriers. This work reveals an operable pathway for fabricating promising photocatalyst for visible-light-driven solar-to-fuel generation and provides insight into the impact of the integration of Co QDs on COF-based photocatalysts.

Construction of a novel supramolecular self‐assembly photocatalyst for full visible light spectrum photooxidation of phenol

AbstractThe sluggish full visible light response of organic supramolecular catalysts is a challenge that greatly restricts their development in the photocatalytic field. Herein, we successfully fabricated a K, Cl‐codoped Bi2WO6/perylene‐diimide(PDI) catalyst with a novel, general, and facile ultrasound assisted water bath heating method. The UV adsorption onset of K, Cl‐codoped Bi2WO6/PDI is redshifted from 750 to 760 nm compared with that of the heterojunction of Bi2WO6/PDI. Under visible light, the phenol is thoroughly mineralized into CO2 and H2O, and the phenol degradation rate was three times higher than that of pure Bi2WO6/PDI. The electrons transfer from PDI to K‐ and Cl‐codoped Bi2WO6/PDI according to the charge density difference calculation. The built‐in potential of K‐ and Cl‐codoped Bi2WO6/PDI could increase from 2.09 to 5.54 eV. The excellent full visible light spectrum photooxidation of phenol is attributed to the suitably strong built‐in potential at the heterojunction between PDI and K, Cl‐codoped Bi2WO6.

Thermal-stability resonators for visible light full-spectrum perfect absorbers

Perfect light absorption is desirable for applications in the devices related to photo-electrical effects, photo-thermal process and photo-chemical/catalysis solutions, etc. In this work, we propose and demonstrate a feasible way to achieve broadband perfect absorption in the full visible range based on the refractory material resonators. This structure shows excellent absorption efficiency with the average absorption up to 94% in the wavelength range from 380 nm to 760 nm (the visible region), suggesting the impressive capability of energy harvesting. The photonic cavity mode and the dipolar plasmon resonance by the half-cylinder cavity structure are the main contributions for the broadband absorption. The full-spectrum visible light absorption is observed to be maintained in a wide angle range under the oblique illumination. The high absorption is also retained under different polarization states. Moreover, the resonant materials such as titanium dioxide (TiO2) and titanium nitride (TiN) have impressive thermal stability due to their high melting points. These findings pave new insights on the refractory perfect visible light absorber for nano-scale photo-thermal process, micro-fluidic thermal disinfect and local high-temperature process, etc.

Multiwavelength-Steerable Visible-Light-Driven Magnetic CoO-TiO2 Microswimmers.

While current light-driven microswimmers require high-intensity light, UV light, or toxic fuels to propel them, powering them with low-intensity UV-free visible light without fuels is essential to enable their potential high-impact applications. Therefore, in this study, a new material for light-driven microswimmers in the form of CoO is introduced. Janus CoO–TiO2 microswimmers powered with low-intensity, UV-free visible light inside water without using any toxic fuels like H2O2 is proposed. The microswimmers show propulsion under full spectrum of visible light with 17 times lower intensity than the mean solar intensity. They propel by breaking down water into oxygen and oxide radicals, which enables their potential applications for photocatalysis and drug delivery. The microswimmers are multiwavelength responsive, from the ultraviolet to the infrared region. The direction of swimming changes with the change in the illumination from the visible to UV light. In addition to being responsive, they are wavelength steerable and exhibit inherent magnetic properties enabling magnetic steering control of the CoO–TiO2 microswimmers. Thus, these microswimmers, which are propelled under low-intensity visible light, have direction-changing capability using light of different wavelengths, and have steering control capability by external magnetic fields, could be used in future potential applications, such as active and local cargo delivery, active photocatalysis, and hydrogen evolution.

Efficient Hybrid Tandem Solar Cells Based on Optical Reinforcement of Colloidal Quantum Dots with Organic Bulk Heterojunctions

AbstractWhile colloidal quantum dot photovoltaic devices (CQDPVs) can achieve a power conversion efficiency (PCE) of ≈12%, their insufficient optical absorption in the near‐infrared (NIR) regime impairs efficient utilization of the full spectrum of visible light. Here, high‐efficiency, solution‐processed, hybrid series, tandem photovoltaic devices are developed featuring CQDs and organic bulk heterojunction (BHJ) photoactive materials for front‐ and back‐cells, respectively. The organic BHJ back‐cell efficiently harvests the transmitted NIR photons from the CQD front‐cell, which reinforces the photon‐to‐current conversion at 350–1000 nm wavelengths. Optimizing the short‐circuit current density balance of each sub‐cell and creating a near ideal series connection using an intermediate layer achieve a PCE (12.82%) that is superior to that of each single‐junction device (11.17% and 11.02% for the CQD and organic BHJ device, respectively). Notably, the PCE of the hybrid tandem device is the highest among the reported CQDPVs, including single‐junction devices and tandem devices. The hybrid tandem device also exhibits almost negligible degradation after air storage for 3 months. This study suggests a potential route to improve the performance of CQDPVs by proper hybridization with NIR‐absorbing photoactive materials.

N-doped graphene-wrapped TiO2 nanotubes with stable surface Ti3+ for visible-light photocatalysis

Due to the merits of visible-light absorption and high conductivity, Ti3+ is a main focus among the modifications of TiO2. However, surface Ti3+ is unstable. Herein, surface-stable Ti3+ in an N-doped rGO-coated TiO2 nanotube sample is prepared. The N-doping introduced Ti-C bonds and an abundance of surface Ti3+, which produced several mid-gap states. These properties allow the composite to absorb nearly the full visible-light spectrum. Owing to the advantages of a broad visible-light absorption, short diffusion distance in the nanotube, and a good heterojunction, the composite exhibits a good photocatalytic activity. Under visible light and without Pt as a cocatalyst, methylene blue was degraded within 40 mins, and the H2 production rate is as high as 720 µmol g−1 h−1. Due to the synergistic effect of N doping and Ti-C bond formation, the configuration of surface Ti3+ is stabilized by a charge-transfer resonance mechanism. The tightly coated graphene also plays a vital role in protecting the surface Ti3+. Even after storage for one year, the photocatalytic activity and the EPR signal intensity from Ti3+ paramagnetic states remain unchanged within experimental error. It suggests that the surface Ti3+ concentration, and the properties of the composite are stable with time.

A general strategy for development of a single benzene fluorophore with full-color-tunable, environmentally insensitive, and two-photon solid-state emission.

We report here a single-benzene based fluorescent framework, amino-terephthalonitrile, denoted SB-Fluor. This scaffold displays versatile emission wavelength tunability via structure modification, covering the full visible light spectrum, both in the solution and solid state. Moreover, one molecule, SBF3, exhibits polymorphism-dependent reversible mechanochromic luminescence.

(Invited) Micro- and Nano-Structure p-n Junction Based Organophotochatalyst Film

The present paper describes organic semiconductor based photocatalyst with p-n junction. A typical material combination is phthalocyanine (H2Pc) and 3,4,9,10-perylenetetracarboxylic-bis-benzimidazole (PTCBI) without transition metal element. It responds full spectrum of visible light and reaching to near infrared region. The film type photocatalyst was prepared by vapor deposition technique with the thickness around 10 to 100 nm, which is relating to absorbance. Typical applicable reactions are downhill redox reaction such as mineralization of volatile organic molecules. The engineering quantum efficiency per incident photon number is high >10 %. When the combination is modified with noble metal nanoparticles or transition metal ion into phthalocyanine, water reduction and oxidation occurred in the presence of bias potential under visible light illumination. Due to the film structure, layering of the film is possible for a practical application, and it is useful to utilise natural sunlight. Under the weak light illumination, internal quantum efficiency becomes high which is merit for the layering use. By changing microstructure and nanostucture of p-n junction, interesting enhancements were observed, such as near infrared region response maybe due to charge transfer complex formation between H2Pc and PTCBI. A terrace bilayer (TB) of p-n junction exhibited potential structure at the interface and it was observed by the use of scanning Kelvin probe microscopy (SKPM). 1) K. Nagai et al. ChemSusChem, 4 (6), 727-730, (2011). 2) K. Nagai et al. ACS Sustainable Chem. Eng., 1, (8), 1033-1039, (2013). 3) M.-F. Ahmad et al. Electrochemistry ., 86, in press, (2018).

Solution Processable 1D Fullerene C60 Crystals for Visible Spectrum Photodetectors.

Visible spectrum photodetector devices fabricated using molecular crystals of carbon C60 are reported. The devices operate efficiently, extending over and beyond the full visible light spectrum (300-710 nm) with a bias voltage tunable responsivity of 4 mA-0.5 mA W-1 . Across this range of wavelengths, the noise equivalent power of these devices remains below 102 nW Hz-1/2 , providing a detectivity of 107 Jones. The noise current in these devices is found to have a strong dependence on both bias voltage and frequency, varying by 4 orders of magnitude from 1 nA Hz-1/2 to 0.1 pA Hz-1/2 . The devices also display a near-linear dependence of photocurrent on light intensity over 4 orders of magnitude, providing a dynamic range approaching 80 dB. The 3 dB bandwidth of the devices is found to be above 102 Hz, while the 18 dB bandwidth exceeds 1 kHz. The transient photocurrents of the devices have a rise time of ≈50 µs and a long fall time of ≈4 ms. The spectral photocurrent of the devices is found to quench gradually with a reduction in temperature from ≈300 K and is fully quenched at temperatures below T ≈ 100 K. Upon reheating, the device performance is fully recovered.

An Unusual Strong Visible-Light Absorption Band in Red Anatase TiO2 Photocatalyst Induced by Atomic Hydrogen-Occupied Oxygen Vacancies.

Increasing visible light absorption of classic wide-bandgap photocatalysts like TiO2 has long been pursued in order to promote solar energy conversion. Modulating the composition and/or stoichiometry of these photocatalysts is essential to narrow their bandgap for a strong visible-light absorption band. However, the bands obtained so far normally suffer from a low absorbance and/or narrow range. Herein, in contrast to the common tail-like absorption band in hydrogen-free oxygen-deficient TiO2 , an unusual strong absorption band spanning the full spectrum of visible light is achieved in anatase TiO2 by intentionally introducing atomic hydrogen-mediated oxygen vacancies. Combining experimental characterizations with theoretical calculations reveals the excitation of a new subvalence band associated with atomic hydrogen filled oxygen vacancies as the origin of such band, which subsequently leads to active photo-electrochemical water oxidation under visible light. These findings could provide a powerful way of tailoring wide-bandgap semiconductors to fully capture solar light.

Phosphorus quantum dots as visible-light photocatalyst for water splitting

The discovery and synthesis of phosphorene stimulate the exploration of other two-dimensional (2D) phosphorus allotropes as well as phosphorus nanostructures. The recent successful preparation of phosphorene quantum dots further broadens the application areas of this novel 2D material. Herein we propose, for the first time, to sculpture monolayer black and blue phosphorus into quantum dots for photocatalytic solar water splitting. The size dependency of electronic, optical and photocatalytic properties of monolayer phosphorus quantum dots are systematically investigated. According to our first-principles calculations, these nanostructures possess highly tunable energy gap and work function; their frontier molecular orbitals straddle the water redox potentials with reasonable oxidizing and reducing power; they can harvest the full spectrum of visible light. Therefore, monolayer phosphorus quantum dots are promising candidates of visible-light photocatalysts for water splitting.

Highly Efficient Organic Photocatalyst with Full Visible Light Spectrum through π-π Stacking of TCNQ-PTCDI.

Self-assembled TCNQ-PTCDI composite photocatalysts can not only degrade phenol at a rate of 0.154 h-1, which is 10.4 times higher than that of pure PTCDI, but also produce oxygen at a rate of ∼14 μmol·g-1·h-1 without cocatalysts. The π-π interactions between TCNQ and PTCDI result in fast transfer of carriers and reduced carrier recombination. The interaction lowers the valence band and narrows the band gap, thus leading to a stronger oxidizability and a broad spectral response (∼730 nm). Moreover, the presence of TCNQ stabilizes the composite to decrease the accumulation of negative charge, which results in an excellent stability of the composite. The high catalytic activity can potentially be utilized in the fields of environmental and energy applications.

Full Spectrum Visible LED Light Activated Antibacterial System Realized by Optimized Cu2O Crystals.

Assisted by three-dimensional printing technology, we proposed and demonstrated a full spectrum visible light activated antibacterial system by using a combination of 500 nm sized Cu2O crystals and light-emitting diode (LED) lamps. Further improved antibacterial ratios were achieved, for the first time, with pure Cu2O for both Gram-positive bacteria and Gram-negative bacteria among all of the six different color LED lamps. For practical antibacterial applications, we revealed that the nonwoven fabric could act as excellent carrier for Cu2O crystals and provide impressive antibacterial performance. Furthermore, integrated with our self-developed app, the poly(ethylene terephthalate) film loaded with Cu2O crystals also showed significant antibacterial property, thus making it possible to be applied in field of touch screen. The present research not only provided a healthier alternative to traditional ultraviolet-based sterilization but also opened an auto-response manner to decrease the rate of microbial contamination on billions of touch screen devices.

Laser-Modified Black Titanium Oxide Nanospheres and Their Photocatalytic Activities under Visible Light.

A facile pulse laser ablation approach for preparing black titanium oxide nanospheres, which could be used as photocatalysts under visible light, is proposed. The black titanium oxide nanospheres are prepared by pulsed-laser irradiation of pure titanium oxide in suspended aqueous solution. The crystalline phases, morphology, and optical properties of the obtained nanospheres are characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV-vis-NIR diffuse reflectance spectroscopy. It is shown that high-energy laser ablation of titanium oxide suspended solution benefited the formation of Ti(3+) species and surface disorder on the surface of the titanium oxide nanospheres. The laser-modified black titanium oxide nanospheres could absorb the full spectrum of visible light, thus exhibiting good photocatalytic performance under visible light.

The fluorescence detection of glutathione by ∙OH radicals’ elimination with catalyst of MoS2/rGO under full spectrum visible light irradiation

In this study, a new method for the detection of glutathione (GSH) was designed based on the ∙OH radicals’ elimination system due to the reducing ability of GSH for the first time. Fluorescence method with terephthalic acid (TA) as the probe was employed for the quantification of ∙OH radicals’ production and elimination. Experimental conditions of ∙OH radicals’ production were optimized in detail, and ∙OH radicals were found to be efficiently produced by the excellent catalysis performance of MoS2/rGO under full spectrum visible light irradiation. The introduction of GSH make fluorescent intensity decrease due to the elimination of ∙OH radicals. For the present fluorescence based GSH sensor, a wide detection range of 60.0–700.0µM and excellent selectivity have been achieved. Furthermore, it has been successfully employed for the determination of GSH in commercial drug tablets and human serum.

Red Phosphorus: An Earth-Abundant Elemental Photocatalyst for "Green" Bacterial Inactivation under Visible Light.

Earth-abundant red phosphorus was found to exhibit remarkable efficiency to inactivate Escherichia coli K-12 under the full spectrum of visible light and even sunlight. The reactive oxygen species (•OH, •O2(-), H2O2), which were measured and identified to derive mainly from photogenerated electrons in the conduction band using fluorescent probes and scavengers, collectively contributed to the good performance of red phosphorus. Especially, the inactivated-membrane function enzymes were found to be associated with great loss of respiratory and ATP synthesis activity, the kinetics of which paralleled cell death and occurred much earlier than those of cytoplasmic proteins and chromosomal DNA. This indicated that the cell membrane was a vital first target for reactive oxygen species oxidation. The increased permeability of the cell membrane consequently accelerated intracellular protein carboxylation and DNA degradation to cause definite bacterial death. Microscopic analyses further confirmed the cell destruction process starting with the cell envelope and extending to the intracellular components. The red phosphorus still maintained good performance even after recycling through five reaction cycles. This work offers new insight into the exploration and use of an elemental photocatalyst for "green" environmental applications.