Photonic Band Gap in 1D Multilayers Made by Alternating SiO2 or PMMA with MoS2 or WS2 monolayers

Atomically thin molybdenum disulphide (MoS2) and tungsten disulphide (WS2) are very interesting two dimensional materials for optics and electronics. In this work we show the possibility to obtain one-dimensional photonic crystals consisting of low-cost and easy processable materials, as silicon dioxide (SiO2) or poly methyl methacrylate (PMMA), and of MoS2 or WS2 monolayers. We have simulated the transmission spectra of the photonic crystals using the transfer matrix method and employing the wavelength dependent refractive indexes of the materials. This study envisages the experimental fabrication of these new types of photonic crystals for photonic and light emission applications.Comment: 8 pages, 5 figure

Control of the chemiluminescence spectrum with porous Bragg mirrors

Tunable, battery free light emission is demonstrated in a solid state device that is compatible with lab on a chip technology and easily fabricated via solution processing techniques. A porous one dimensional (1D) photonic crystal (also called Bragg stack or mirror) is infiltrated by chemiluminescence rubrene-based reagents. The Bragg mirror has been designed to have the photonic band gap overlapping with the emission spectrum of rubrene. The chemiluminescence reaction occurs in the intrapores of the photonic crystal and the emission spectrum of the dye is modulated according to the photonic band gap position. This is a compact, powerless emitting source that can be exploited in disposable photonic chip for sensing and point of care applications.Comment: 8 pages, 3 figure

Phosphorimetric Characterization of Solution-Processed Polymeric Oxygen Barriers for the Encapsulation of Organic Electronics

We describe the use of a modified Stern-Volmer photokinetic model for the determination of the oxygen-permeation coefficient (PO2) of materials that can be used as barriers against oxygen permeation in organic electronic applications. The model is applied on photophysical data collected based on the use of the optical technique of phosphorimetry for the oxygen-sensing organometallic complex (2,3,7,8,12,13,17,18-octaethylporphyrinato)platinum(II) (PtOEP). PtOEP is used as a phosphorescent probe encapsulated by a set of model solution-processed transparent oxygen-barrier layers made by the polymers of poly(norbornene), poly(methyl methacrylate), poly(styrene), and Zeonex. For each barrier system the oxygen-induced quenching of the PtOEP phosphorescence is monitored with the study of the time-integrated and time-resolved PtOEP phosphorescence intensity, as a function of the partial pressure of oxygen. The advantage of utilizing the presented photokinetic model is based on the consideration of the fractional accessibility of the excited triplet states to the permeant oxygen. The extracted values of PO2 are in excellent agreement with the previous literature, confirming the validity of the modified Stern-Volmer model employed in the analysis of the photophysical data. The results suggest that phosphorimetric characterization is a simple and inexpensive methodology for the fast screening of next-generation barrier materials for organic electronic devices. The high sensitivity of the phosphorimetric technique is shown in the successful characterization of a commonly used glass/epoxy barrier system for which PO2 = 39 × 10-16 cm3 (STP) ·cm·cm -2·s-1·Pa-1 is found. The findings of the phosphorimetric characterization are in qualitative agreement with a preliminary shelf lifetime stability test of organic solar cell devices that were encapsulated with some of the barrier materials of the study. © 2014 American Chemical Society

Phosphorimetric Characterization of Solution-Processed Polymeric Oxygen Barriers for the Encapsulation of Organic Electronics

We describe the use of a modified Stern-Volmer photokinetic model for the determination of the oxygen-permeation coefficient (PO2) of materials that can be used as barriers against oxygen permeation in organic electronic applications. The model is applied on photophysical data collected based on the use of the optical technique of phosphorimetry for the oxygen-sensing organometallic complex (2,3,7,8,12,13,17,18-octaethylporphyrinato)platinum(II) (PtOEP). PtOEP is used as a phosphorescent probe encapsulated by a set of model solution-processed transparent oxygen-barrier layers made by the polymers of poly(norbornene), poly(methyl methacrylate), poly(styrene), and Zeonex. For each barrier system the oxygen-induced quenching of the PtOEP phosphorescence is monitored with the study of the time-integrated and time-resolved PtOEP phosphorescence intensity, as a function of the partial pressure of oxygen. The advantage of utilizing the presented photokinetic model is based on the consideration of the fractional accessibility of the excited triplet states to the permeant oxygen. The extracted values of PO2 are in excellent agreement with the previous literature, confirming the validity of the modified Stern-Volmer model employed in the analysis of the photophysical data. The results suggest that phosphorimetric characterization is a simple and inexpensive methodology for the fast screening of next-generation barrier materials for organic electronic devices. The high sensitivity of the phosphorimetric technique is shown in the successful characterization of a commonly used glass/epoxy barrier system for which PO2 = 39 × 10-16 cm3 (STP) ·cm·cm -2·s-1·Pa-1 is found. The findings of the phosphorimetric characterization are in qualitative agreement with a preliminary shelf lifetime stability test of organic solar cell devices that were encapsulated with some of the barrier materials of the study. © 2014 American Chemical Society

Phosphorimetric Characterization of Solution-Processed Polymeric Oxygen Barriers for the Encapsulation of Organic Electronics

We describe the use of a modified Stern–Volmer photokinetic model for the determination of the oxygen-permeation coefficient (<i>P</i>^O₂) of materials that can be used as barriers against oxygen permeation in organic electronic applications. The model is applied on photophysical data collected based on the use of the optical technique of phosphorimetry for the oxygen-sensing organometallic complex (2,3,7,8,12,13,17,18-octaethylporphyrinato)­platinum­(II) (PtOEP). PtOEP is used as a phosphorescent probe encapsulated by a set of model solution-processed transparent oxygen-barrier layers made by the polymers of poly­(norbornene), poly­(methyl methacrylate), poly­(styrene), and Zeonex. For each barrier system the oxygen-induced quenching of the PtOEP phosphorescence is monitored with the study of the time-integrated and time-resolved PtOEP phosphorescence intensity, as a function of the partial pressure of oxygen. The advantage of utilizing the presented photokinetic model is based on the consideration of the fractional accessibility of the excited triplet states to the permeant oxygen. The extracted values of <i>P</i>^O₂ are in excellent agreement with the previous literature, confirming the validity of the modified Stern–Volmer model employed in the analysis of the photophysical data. The results suggest that phosphorimetric characterization is a simple and inexpensive methodology for the fast screening of next-generation barrier materials for organic electronic devices. The high sensitivity of the phosphorimetric technique is shown in the successful characterization of a commonly used glass/epoxy barrier system for which <i>P</i>^O₂ = 39 × 10^–16 cm³ (STP) ·cm·cm^–2·s^–1·Pa^–1 is found. The findings of the phosphorimetric characterization are in qualitative agreement with a preliminary shelf lifetime stability test of organic solar cell devices that were encapsulated with some of the barrier materials of the study

Structural color tuning in a Ag/TiO2 nanoparticle one-dimensional photonic crystal induced by electric field

We present the electric field-induced tuning of the light transmission in a photonic crystal device. The device, with alternating layers of Silver and Titanium dioxide nanoparticles, shows a shift of around 10 nm for an applied voltage of 10 V. An accumulation of charges at the Silver/TiO2 interface due to electric field leads to an increase of the number of charges contributing to the plasma frequency in Silver. This results in a blue shift of the Silver plasmon band, with concomitant blue shift of the photonic band gap as a result of the decrease in the Silver dielectric function

PET Imaging of the Neurotensin Targeting Peptide NOTA-NT-20.3 Using Cobalt-55, Copper-64 and Gallium-68

Introduction: Neurotensin receptor 1 (NTSR1) is an emerging target for imaging and therapy of many types of cancer. Nuclear imaging of NTSR1 allows for noninvasive assessment of the receptor levels of NTSR1 on the primary tumor, as well as potential metastases. This work focuses on a the neurotensin peptide analogue NT-20.3 conjugated to the chelator NOTA for radiolabeling for use in noninvasive positron emission tomography (PET). NOTA-NT-20.3 was radiolabeled with gallium-68, copper-64, and cobalt-55 to determine the effect that modification of the radiometal has on imaging and potential therapeutic properties of NOTA-NT-20.3. Methods: In vitro assays investigating cell uptake and subcellular localization of the radiolabeled peptides were performed using human colorectal adenocarcinoma HT29 cells. In vivo PET/CT imaging was used to determine the distribution and clearance of the peptide in mice bearing NTSR1 expressing HT29 tumors. Results: Cell uptake studies showed that the highest uptake was obtained with [55Co] Co-NOTA-NT-20.3 (18.70 ± 1.30%ID/mg), followed by [64Cu] Cu-NOTA-NT-20.3 (15.46 ± 0.91%ID/mg), and lastly [68Ga] Ga-NOTA-NT-20.3 (10.94 ± 0.46%ID/mg) (p 55Co] Co-NOTA-NT-20.3 (20.28 ± 3.04) outperformed [64Cu] Cu-NOTA-NT-20.3 (6.52 ± 1.97). In conclusion, our studies show that enhanced cell uptake and increasing tumor to blood ratios over time displayed the superiority of [55Co] Co-NOTA-NT-20.3 over [68Ga] Ga-NOTA-NT-20.3 and [64Cu] Cu-NOTA-NT-20.3 for the targeting of NTSR1

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

An electric field is employed for the active tuning of the structural colour in photonic crystals, which acts as an effective external stimulus with an impact on light transmission manipulation. In this work, we demonstrate structural colour in a photonic crystal device comprised of alternating layers of silver nanoparticles and titanium dioxide nanoparticles, exhibiting spectral shifts of around 10 nm for an applied voltage of only 10 V. The accumulation of charge at the metal/dielectric interface with an applied electric field leads to an effective increase of the charges contributing to the plasma frequency in silver. This initiates a blue shift of the silver plasmon band with a simultaneous blue shift of the photonic band gap as a result of the change in the silver dielectric function (i.e. decrease of the effective refractive index). These results are the first demonstration of active colour tuning in silver/titanium dioxide nanoparticle-based photonic crystals and open the route to metal/dielectric-based photonic crystals as electro-optic switches