Large Modulation Research Articles

Testing Cosmic-Ray Propagation Scenarios with AMS-02 and Voyager Data

AMS-02 on board the International Space Station provides precise measurements of cosmic rays (CR) near Earth, while Voyager measures CRs in the local interstellar medium, beyond the effects of solar modulation. Based on these data, we test and revise various CR propagation scenarios under standard assumptions: pure diffusion, diffusion with convection, diffusion with reacceleration, and diffusion with reacceleration and convection. We report on the scenarios’ performance against CR measurements, aiming to limit the number of model parameters as much as possible. For each scenario, we find parameters that are able to reproduce Voyager and AMS-02 data for the entire energy band for all the CR species tested. Above several GV, we observe a similar injection spectral index for He and C, with He harder than H. Some scenarios previously disfavored are now reconsidered. For example, contrary to usual assumptions, we find that the pure diffusion scenario does not need an upturn in the diffusion coefficient at low energy, while it needs the same number of low-energy breaks in the injection spectrum as diffusive-reacceleration scenarios. We show that scenarios differ in modeled spectra of one order of magnitude for positrons at ∼1 GeV and of a factor of 2 for antiprotons at several GV. The force-field approximation describes well the AMS-02 and Voyager spectra analyzed, except antiprotons. We confirm the ∼10 GeV excess in the antiproton spectrum for all scenarios. Also, for all scenarios, the resulting modulation should be stronger for positrons than for nuclei, with reacceleration models requiring much larger modulation.

Effectiveness of Telemedicine Interventions in Chronic Obstructive Pulmonary Disease (COPD) Management: A Randomized Controlled Trial Comparing Yoga Therapy and Pulmonary Rehabilitation Over Three Months.

Background Pulmonary rehabilitation (PR) is an integral part of non-pharmacological therapy in chronic obstructive pulmonary disease (COPD). Yoga therapy (YT) has been shown to be beneficial in COPD, but the lack of large well-designed trials and standardized modules restricts its acceptability. This randomized control trial compares these two modalities in COPD patients via supervised tele-intervention. Objectives The primary objective of the study is to compare a 45-minute, five-days-per-week series of tele-YT (T-YT) with tele-PR (T-PR) for three months in terms of exercise capacity (6-Minute Walk Distance (6MWD)) in COPD patients. Methods COPD patients were randomly assigned (1:1) to T-YT or T-PR groups in a parallel-arm single-blinded controlled trial. The primary outcome is 6MWD recorded at baseline and after three months and secondary outcomes were symptom scores, Forced expiratory volume in the first second (FEV1), health-related quality of life (HrQoL), and depression and anxiety scores. Assessments were conducted at baseline and at the end of the three-month study period with a sample size of 75 in each group. Results A total of 150 consecutive patients with COPD were randomly assigned to either the T-YT (n = 75) or T-PR (n = 75) group. Their mean ± SD ages was 62.5 ± 7.0 years. The T-YT group had 55.5% males and 34.47% females, whereas the T-PR group had 44.5% males and 61.53% females. The trial was completed by 123 patients; 88% in the T-YT group and 76% in the T-PR group. Pre-intervention, the median (range)of 6MWD in T-YT and T-PR groups was 240 (120-600) m and 240 (120-660) m, respectively. There was statistically significant improvement in both groups respectively (p<0.001) post intervention from baseline but no significant intergroup difference (p = 0.486). A similar trend was seen in secondary outcomes with significant intragroup improvements and non-significant inter-group differences except FEV1%, which showed neither intragroup nor intergroup significant improvement. Conclusion Using a validated module, a three-month T-YT improves exercise capacity, symptom scores, HrQoL, and depression and anxiety scores similar to T-PR. T-YT is an acceptable alternative toT-PR in the management of COPD.

Tuning exciton dynamics by the dielectric confinement effect in quasi-two-dimensional perovskites

The dielectric confinement effect plays an essential role in optoelectronic devices. Existing studies on the relationship between the dielectric confinement and the photoelectric properties are inadequate. Herein, three organic spacers with different dielectric constants are employed to tune the exciton dynamics of quasi-two-dimensional (quasi-2D) Ruddlesden–Popper perovskite films. Femtosecond transient absorption spectroscopy reveals that the small dielectric constant ligand enables a weak dynamic disorder and a large modulation depth of the coherent phonons, resulting in a more complete energy transfer and the inhibition of a trap-mediated nonradiative recombination. Additionally, the increase in the bulk-ligand dielectric constant reduces the corresponding exciton binding energy and then suppresses the Auger recombination, which is beneficial for high-luminance light-emitting diodes. This work emphasizes the importance of dielectric confinement for regulating the exciton dynamics of layered perovskites.

Transfer of disulfide bond formation modules via yeast artificial chromosomes promotes the expression of heterologous proteins in Kluyveromyces marxianus.

Kluyveromyces marxianus is a food-safe yeast with great potential for producing heterologous proteins. Improving the yield in K. marxianus remains a challenge and incorporating large-scale functional modules poses a technical obstacle in engineering. To address these issues, linear and circular yeast artificial chromosomes of K. marxianus (KmYACs) were constructed and loaded with disulfide bond formation modules from Pichia pastoris or K. marxianus. These modules contained up to seven genes with a maximum size of 15 kb. KmYACs carried telomeres either from K. marxianus or Tetrahymena. KmYACs were transferred successfully into K. marxianus and stably propagated without affecting the normal growth of the host, regardless of the type of telomeres and configurations of KmYACs. KmYACs increased the overall expression levels of disulfide bond formation genes and significantly enhanced the yield of various heterologous proteins. In high-density fermentation, the use of KmYACs resulted in a glucoamylase yield of 16.8 g/l, the highest reported level to date in K. marxianus. Transcriptomic and metabolomic analysis of cells containing KmYACs suggested increased flavin adenine dinucleotide biosynthesis, enhanced flux entering the tricarboxylic acidcycle, and a preferred demand for lysine and arginine as features of cells overexpressing heterologous proteins. Consistently, supplementing lysine or arginine further improved the yield. Therefore, KmYAC provides a powerful platform for manipulating large modules with enormous potential for industrial applications and fundamental research. Transferring the disulfide bond formation module via YACs proves to be an efficient strategy for improving the yield of heterologous proteins, and this strategy may be applied to optimize other microbial cell factories.

Development and Challenges of Large‐Area All‐Perovskite Tandem Solar Cells and Modules

The efficiency of all‐perovskite tandem solar cells has recently surpassed that of single‐junction perovskite solar cells, showing great potential as a future photovoltaic technology due to its low manufacturing cost and high power conversion efficiency potential, yet the size of these cells is still at the laboratory level. It is highly required to develop scalable preparation methods to fabricate large‐area all‐perovskite tandem solar modules for commercial applications. Herein, the key challenges encountered in the laboratory of all‐perovskite tandem solar cells and the existing solutions are summarized and some views on the preparation of large areas and modules are given.

All-optical ultrafast polarization switching with nonlinear plasmonic metasurfaces.

Optical switching has important applications in optical information processing, optical computing, and optical communications. The long-term pursuit of optical switch is to achieve short switching time and large modulation depth. Among various mechanisms, all-optical switching based on Kerr effect represents a promising solution. However, it is usually difficult to compromise both switching time and modulation depth of a Kerr-type optical switch. To circumvent this constraint, symmetry selective polarization switching via second-harmonic generation (SHG) in nonlinear crystals has been attracting scientists' attention. Here, we demonstrate SHG-based all-optical ultrafast polarization switching by using geometric phase controlled nonlinear plasmonic metasurfaces. A switching time of hundreds of femtoseconds and a modulation depth of 97% were experimentally demonstrated. The function of dual-channel all-optical switching was also demonstrated on a metasurface, which consists of spatially variant meta-atoms. The nonlinear metasurface proposed here represents an important platform for developing all-optical ultrafast switches and would benefit the area of optical information processing.

Full-Color "Off-On" Thermochromic Fluorescent Fibers for Customizable Smart Wearable Displays in Personal Health Monitoring.

Responsive thermochromic fiber materials capable of miniaturization and integrating comfortably and compliantly onto the soft and dynamically deforming human body are promising materials for visualized personal health monitoring. However, their development is hindered by monotonous colors, low-contrast color changes, and poor reversibility. Herein, full-color "off-on" thermochromic fluorescent fibers are prepared based on self-crystallinity phase change and Förster resonance energy transfer for long-term and passive body-temperature monitoring, especially for various personalized customization purposes. The off-on switching luminescence characteristic is derived from the reversible conversion of the dispersion state and fluorescent emission by fluorophores and quencher molecules, which are embedded in the matrix of a phase-change material, during the crystallizing/melting processes. The achievement of full-color fluorescence is attributed to the large modulation range of fluorescence colors according to primary color additive theory. These thermochromic fluorescent fibers exhibit good mechanical properties, fluorescent emission contrast, and reversibility, showing their great potential in flexible smart display devices. Moreover, the response temperature of the thermochromic fibers is controllable by adjusting the phase-change material, enabling body-temperature-triggered luminescence; this property highlights their potential for human body-temperature monitoring and personalized customization. This work presents a new strategy for designing and exploring flexible sensors with higher comprehensive performances.

A semi-solid, polychromatic dual-band electrochromic smart window: Visualizing sunlight and solar heat transmission

In this paper, a novel semi-solid, polychromatic dual-band electrochromic smart window was constructed by organically assembling monoclinic WO3-x nanowires (m-WO3-x NWs), AlCl3-polyvinyl alcohol (PVA) and polyaniline (PANI). The device not only presented the independent regulation of “bright”, “cool” and “dark”, but also exhibited excellent comprehensive performance, including large optical modulation (74.9 % and 79.1 % at 700 and 2000 nm, respectively.), short coloring/bleaching times (7.6/2.7 and 6.7/3.9 s at 700 and 1200 nm, respectively), and good stability and reversibility (the capacity decreased by 4.3 % and the coulombic efficiency stabled at 99.2 % after 1000 cycles). In addition, the multi-colored PANI endowed the window with the ability to visually monitor modulation modes, as well as indoor sunlight and thermal transmittance. The transparent, green, and blue represented “bright”, “cool”, and “dark” modes, and the depth of the color stood for the control effect in a certain mode. Moreover, the dual-band modulation and polychromatic conversion mechanisms of individual electrodes and the smart window prototype were also elucidated in detail. The modulation of near-infrared light mainly comes from the localized surface plasmon resonance (LSPR) absorption and the phase transition of m-WO3-x NWs, as well as the generated polarons and bipolarons of PANI. While the selective absorption of visible light was related to the bandgap transition of m-WO3-x NWs and the electronic transition of the quinone unit. Surprisingly, the smart window could achieve a maximum decrease of 4.3 °C by controlling the “bright-dark” mode transition in real application simulations, significantly boosting the process of low carbon environmental protection and the construction of energy-saving buildings.

Lateral junctions of transition metal dichalcogenides as ballistic channels for straintronic applications

In the context of advanced nanoelectronics, two-dimensional semiconductors such as transition metal dichalcogenides (TMDs) are gaining considerable interest due to their ultimate thinness, clean surface and high carrier mobility. The engineering prospects offered by those materials are further enlarged by the recent realization of atomically sharp TMD-based lateral junctions, whose electronic properties are governed by strain effects arising from the constituents lattice mismatch. Although most theoretical studies considered only misfit strain, first-principles simulations are employed here to investigate the transport properties under external deformation of a three-terminal device constructed from a MoS2/WSe2/MoS2 junction. Large modulation of the current is reported owing to the change in band offset, illustrating the importance of strain on the p–n junction characteristics. The device operation is demonstrated for both local and global deformations, even for ultra-short channels, suggesting potential applications for ultra-thin body straintronics.

Photoinduced Puffing with Large Volume Expansion and Photomechanical Motions induced by Topochemical [4+4] Reactions in Molecular Crystal Solvates.

In this work, we report the first example of two crystal solvates of an anthracene-benzhydrazide based molecule (Ant) that display very distinct photo-responsive behaviour when 365 or 405 nm or visible light is illuminated. For the first time, the crystal hydrate that has water molecule in the lattice (hereafter named as Ant-H2O) display fascinating puffing behavior with large volume expansion upto 50 % accompanied with surface modulation when illuminated with 405 nm light, a phenomenon very much similar to the rice or popcorn puffing by thermal treatment. Utilizing the properties of photoconverted Ant-H2O crystals, we have demonstrated their application in photoinduced enhanced liquid absorption using various liquids/solutions. The other crystal solvate having DMF in the crystal lattice (hereafter named as Ant-DMF) responds to 405 nm light by bending, twisting, chopping, jumping or splitting etc. The chopping of Ant-DMF crystal was also observed under ambient/white light but at a slower rate compared to 405 nm light. Single crystal X-ray diffraction study reveals that the photoinduced puffing and photomechanical effects of these materials are rooted to the topochemical [4+4] cycloaddition reaction between the anthracene moieties that facilitate molecular packing change assisted by the reconfiguration of intermolecular non-covalent interactions involving lattice trapped solvent molecules.

The Bi–O edge wavefront sensor

Context. Direct detection of exoplanets around nearby stars requires advanced adaptive optics (AO) systems. High-order systems are needed to reach a high Strehl ratio (SR) in near-infrared and optical wavelengths on future giant segmented-mirror telescopes (GSMTs). Direct detection of faint exoplanets with the European Southern Observatory (ESO) Extremely Large Telescope (ELT) will require some tens of thousands of correction modes. The resolution and sensitivity of the wavefront sensor (WFS) are key requirements for this science case. We present a new class of WFSs, the bi-orthogonal Foucault knife-edge sensors (or Bi–O edge), that is directly inspired by the Foucault knife-edge test. The idea consists of using a beam-splitter producing two foci, each of which is sensed by an edge with a direction orthogonal to the other focus. Aims. We describe two implementation concepts: The Bi–O edge sensor can be realised with a sharp edge and a tip-tilt modulation device (sharp Bi–O edge) or with a smooth gradual transmission over a grey edge (grey Bi–O edge). A comparison of the Bi–O edge concepts and the four-sided classical pyramid wavefront sensor (PWS) gives some important insights into the nature of the measurements. Methods. We analytically computed the photon noise error propagation, and we compared the results to end-to-end simulations of a closed-loop AO system. Results. Our analysis shows that the sensitivity gain of the Bi–O edge with respect to the PWS depends on the system configuration. The gain is a function of the number of control modes and the modulation angle. We found that for the sharp Bi–O edge, the gain in reduction of propagated photon noise variance approaches a theoretical factor of 2 for a large number of control modes and small modulation angle, meaning that the sharp Bi–O edge only needs half of the photons of the PWS to reach similar measurement accuracy. In contrast, the PWS is twice more sensitive than the Bi–O edge in the case of very low order correction and/or large modulation angles. Preliminary end-to-end simulations illustrate some of the results. The grey version of the Bi–O edge opens the door to advanced amplitude filtering, which replaces the need for a tip-tilt modulator while keeping the same dynamic range. We show that an additional factor of 2 in reduction of propagated photon noise variance can be obtained for high orders, such that the theoretical maximum gain of a factor of 4 in photon efficiency can be obtained. A diffractive Fourier model that accurately includes the effect of modulation and control modes shows that for the extreme AO (XAO) system configuration of the ELT, the overall gain will well exceed one magnitude in guide-star brightness when compared to the modulated PWS. Conclusions. We conclude that the Bi–O edge is an excellent candidate sensor for future very high order Adaptive Optics systems, in particular on GSMTs.

Experimental demonstration of a nanobeam Fano laser.

Microscopic single-mode lasers with low power consumption, large modulation bandwidth, and ultra-narrow linewidth are essential for numerous applications, such as on-chip photonic networks. A recently demonstrated microlaser using an optical Fano resonance between a discrete mode and a continuum of modes to form one of the mirrors, i.e., the so-called Fano laser, holds great promise for meeting these requirements. Here, we suggest and experimentally demonstrate what we believe is a new configuration of the Fano laser based on a nanobeam geometry. Compared to the conventional two-dimensional photonic crystal geometry, the nanobeam structure makes it easier to engineer the phase-matching condition that facilitates the realization of a bound-state-in-the-continuum (BIC). We investigate the laser threshold in two scenarios based on the new nanobeam geometry. In the first, classical case, the gain is spatially located in the part of the cavity that supports a continuum of modes. In the second case, instead, the gain is located in the region that supports a discrete mode. We find that the laser threshold for the second case can be significantly reduced compared to the conventional Fano laser. These results pave the way for the practical realization of high-performance microlasers.

Design and fabrication of indium tin oxide for high performance electro-optic modulators at the communication wavelength

In recent years, transparent conductive oxides(TCO) based electro-optic modulators has garnered significant attention due to its epsilon-near-zero(ENZ) effect to enhance the local optical field and produce a large refractive index change in the vicinity of ENZ wavelength, thereby enabling substantial optical field modulation at micrometer size. The modulators manipulate the light field by altering the carrier concentration in TCO through an electric field. Therefore, the modulator's performance is closely related to the TCO's material behavior. In this paper, the effect of carrier concentration and mobility of indium tin oxide(ITO) on the modulation efficiency, depth and bandwidth was analyzed and it is found that ITO with the carrier concentration near 1 × 1020 cm−3 and mobility as high as 80 cm2/Vs is beneficial to the electro-optic modulators with large modulation depth and bandwidth. Specifically, our research shows that the carrier concentration and mobility of ITO films can be tunned over a wide range from 2.2 × 1019cm−3 to 7.7 × 1020cm−3 and 7.2 cm2/Vs to 82.3 cm2/Vs respectively, by changing doping concentration, deposition conditions and annealing parameters. As a result, ITO film integrated on a 3.5-μm-long silicon waveguide with an MOS structure can achieves a high modulation bandwidth of over 40 GHz at the optical communication wavelength.

Scalable large area perovskite solar cell modules fabricated with high humidity tolerance by vacuum deposition

Vacuum deposition is promising for large-area, high-throughput production of perovskite solar cells (PSCs). However, the strict low humidity control increases the costs for manufacturing facilities and hinders the large-scale production of PSCs. In this work, a sequential deposition method was used to prepare the perovskite intermediate phase, and the impact of ambient humidity was studied during the annealing process. It is shown that proper humidity has a positive effect on the perovskite layer, which is conducive to accelerate the reaction between organic salts and PbI2 and improve the surface morphology of the film. The perovskite annealing under 55 % relative humidity exhibits fewer defects and faster carrier transport kinetics. The resulting PSCs, with all layers fabricated adopting vapor deposition, yield a power conversion efficiency (PCE) of 15.01 % for the large area modules of 100 cm2 (active area 64.8 cm2). More impressively, the PCE of the unpackaged cell modules remained above 80 % after being placed in ambient air for 1200 h. The results open a promising way for scalable fabrication of humidity-tolerant large-area perovskite solar cell modules and shed light on the industrial production of PSCs.

A Highly Efficient and Energy Saving Electrochromic Platform for Adaptive Visible and Near-Infrared Light Modulation

Dual-band electrochromic devices (DBEDs) with reversible optical properties in visible (VIS) and near-infrared (NIR) spectral ranges are highly desirable for intelligent technologies (e.g. electrochromic smart windows, adaptive and military camouflages). However, most available DBEDs only have two optical states - namely the bleached and colored states, and efforts are committed to increasing the optical modulation between them, while durability of cycling is rarely reported. Herein, we report a novel multicolored rocking-chair DBED based on Prussian blue (PB) thin films as electrochromic layers and a conductive carbon cloth (CC) frame as the counter electrode. During the electrochromic process, cations from the electrolyte migrate back and forth between PB and CC, and electrolysis of aqueous electrolyte can be effectively avoided to extend device longevity. The PB-CC DBED exhibits superior dual-band electrochromic performance with a wide range of switchable colors, including transparent, blue, green and yellow, large optical modulation in VIS-NIR ranges, fast response speed, high coloration efficiency and long-term durability. Based on the diverse color change in the VIS range and thermal control in the NIR range, the camouflage ability of the device is also described. Finally, an adaptive optical modulation platform is demonstrated, obtained by connecting the PB-CC device to a voltage-controlled circuit module to realize intelligent and autonomous color switching of the device.

Three‐Dimensional Ordered Macroporous Amorphous WO3 Arrays for Zinc‐Based Electrochromic Device with Large Light Modulation and Fast Switching

AbstractElectrochromic devices have important applications in building energy conservation, next‐generation displaying, and security encryption, while durable and high‐performance electrochromic materials are highly desirable. Herein, a Zn‐based electrochromic smart window by using 3D ordered macroporous amorphous WO3 (a‐WO3) arrays as cathode is reported. Benefiting from a 3D ordered macroporous structure with a high specific surface area that accelerates the ion diffusion and migration, and the oxygen vacancy modulated a‐WO3 providing abundant zinc ion insertion channels, the as‐fabricated zinc‐based a‐WO3 inverse opal (a‐WO3‐IO) device exhibits excellent electrochromic properties, including large light modulation (83% optical contrast at 700 nm), fast response time (5.3 s for coloring and 3.2 s for bleaching), and robust cycling stability. Moreover, a solid‐state a‐WO3‐IO prototype electrochromic smart window is demonstrated for light modulation, electronic display, and power supply. Furthermore, experimental results and theoretical calculations reveal that 3D macroporous amorphous WO3 with rich oxygen vacancies can enhance the zinc ion absorption and diffusion, leading to the enhancement of electrochromic performance.

Tunable and super-wide angle defocusing lens large phase modulator

Traditional terahertz wavefront modulators exhibit significant limitations in controlling optical wavefronts. In order to address the adjustability issues of terahertz wavefront modulators, we have developed a novel optical device based on the tunability of Fermi energy levels. Structurally, we find the ability to modulate the Fermi energy levels of graphene by modulating the carrier concentration. We can also change the phase of the light, causing the transmission path of the light as it passes through the graphene array to change, affecting the position of the backfocusing focal point, thus realizing a dynamically adjustable backfocusing effect. Theoretically, employing Dirac notation and Matrix analyze, reveals the corresponding relationship between Fermi level and phase shift. Specifically, one group Fermi levels induces a set of modulated phase changes. Experimental results demonstrate that the proposed modulator offers a large phase modulation range, enabling 2π phase adjustments. Moreover, it accurately focuses on a predefined focal point located at 400 um, with a numerical aperture of 0.882, a resolution of 30.39, and a full-width at half-maximum of 38. The substantial numerical aperture and small full-width at half-maximum imply that the lens can focus more light while maintaining high resolution, enhanced optical efficiency, and concentrated light focusing. At the same time, by adjusting the position of the Fermi energy level, we have succeeded in realizing a wide-angle focusing effect up to 90°. This capability extends the terahertz wave’s focusing within a wide range, expanding the application scope of traditional focusing devices.

Porous NiMoO4 Nanosheet Films and a Device with Ultralarge Optical Modulation for Electrochromic Energy-Storage Applications.

Reducing building energy consumption, improving aesthetics, and improving occupant privacy as well as comfort by dynamically adjusting solar radiation are important application areas for electrochromic (EC) smart windows. However, the current transition metal oxides still cannot meet the requirements of neutral coloration and large optical modulation. We report NiMoO4 nanosheet films directly grown on fluorine-doped tin oxide glasses. The as-grown NiMoO4 film not only achieves neutral coloration from transparent to dark brown but also shows an ultralarge optical modulation (86.8% at 480 nm) and excellent cycling stability (99.4% retention of maximum optical modulation after 1500 cycles). Meanwhile, an EC device demonstrating good EC performance was constructed. These results will greatly promote the research and development of binary transition metal oxides for both EC and energy-storage applications, and NiMoO4 films may be an excellent candidate to replace NiO films as ion-storage layers in complementary EC devices with WO3 films as EC layers.

Scaling of inverted PTB7-Th: PC71BM organic solar cell for large area organic photovoltaic modules

Abstract Performance studies of large area inverted organic photovoltaic (OPV) modules of configuration ITO/ZnO/PTB7-Th: PC71BM/MoO3/Ag are performed. At a laboratory of scale 0.06 cm2, this device configuration repeatedly demonstrates the power conversion efficiency (PCE) of ∼9%, which is within the range of PCE normally achieved for this configuration. The OPV modules with active area of 9.25 cm2 and 63 cm2 are fabricated employing spin coating techniques comprising a total area 25 cm2 (5 cm × 5 cm) and 144 cm2 (11 cm × 11 cm), respectively. The 25 cm2 module, composed of five cells connected in series show PCE of 3.256%, with short-circuit current (Jsc), open circuit voltage (Voc), and fill factor (FF), 3.210 mAcm−2, 3.20 V, and 31.719%. However, The 144 cm2 modules, composed of 10 cells connected in series show PCE 1.019, Jsc, Voc, and FF, 0.87 mAcm−2, 4.20 V, and 27.877%. The PCE dropped by 63.89% for modules of active area of 9.25 cm2 and 88.68% of modules of active area of 63 cm2. The PCE of the modules is decreased sharply due to loss in FF, and Jsc of the modules. These losses are exhibits due to quality of layer morphology, layer interfaces, and design of module. The PCE could be potentially improved up to the desired value by the further optimization of layer morphology, layer interfaces, design of module geometry, and film deposition/printing methods. The results showed that PTB7-Th: PC71BM is a splendid structure for future organic solar modules due to its high performance and compatibility with large area coatings.

Surface plasmon-cavity hybrid state and its graphene modulation at THz frequencies

Abstract Fabry–Pérot (F–P) cavity and metal hole array are classic photonic devices. Integrating F–P cavity with holey metal typically enhances interfacial reflection and dampens wave transmission. In this work, a hybrid bound surface state is found within rectangular metal holes on a silicon substrate by merging an extraordinary optical transmission (EOT) mode and a high-order F–P cavity mode both spatially and spectrally. Transmission, Q-factor, and bandwidth can be enhanced significantly with respect to the classical EOT and F–P interference by simply sweeping the cavity length. This state can provide EOT properties and ten times broader EOT bandwidth well below the effective plasma frequency of the periodic metal holes, where the metal holes typically show evanescent properties and do not support EOT in theory. Furthermore, a large modulation range of 25 % and 39 % is demonstrated with various graphene patterns for the transmittance of this hybrid state at 500 and 582 GHz, respectively.