Efficient Transmitter Research Articles

Heterojunction interface engineering enabling high transmittance and record efficiency in Sb2S3 semitransparent solar cell

Antimony sulfide (Sb2S3) is an auspicious contender for semitransparent and tandem solar cells owing to its exceptional optoelectronic characteristics. Yet, complex bulk and heterojunction defects hinder achieving optimal power conversion efficiency (PCE). Although CdS is an established electron transport layer (ETL) in Sb-chalcogenide solar cells benefitting from its exceptional electron mobility (350 cm2V–1s−1) and energy level alignments, its potential contribution has been deplorably overlooked in Sb2S3 semitransparent photovoltaics (STPV). Herein, an optimized TiO2/CdS double ETL strategy is embraced to counteract CdS absorption loss and mitigate the “deep cliff” conduction band off-set at TiO2/Sb2S3 heterojunction. Subsequently, an evolved chemical bath deposition strategy is proposed to deposit a uniform, faster, and comparatively more transparent Sb2S3 absorber layer. A systematic investigation of the absorber layer and in-depth analysis of carrier dynamics at heterojunctions advocate for the mitigation of charge accumulation and recombination at the interface, thereby pledging superior carrier transport. The advantageous gradient energy band alignment of TiO2/CdS/Sb2S3 realized a record PCE of 5.61 % for STPV. Furthermore, the semitransparent device is innovatively employed as a window, enabling transmitted light to be harvested by subsequent Sb2S3 solar cells. It maintains 18 % of its standalone PCE, thereby setting new benchmarks for its practical submissions.

Innovations and Challenges in Semi-Transparent Perovskite Solar Cells: A Mini Review of Advancements Toward Sustainable Energy Solutions

Amid the shift away from fossil fuels, third-generation perovskite solar cells (PSCs) have become pivotal due to their high efficiency and low production costs. This review concentrates on semi-transparent perovskite solar cells (ST-PSCs), highlighting their power conversion efficiency (PCE) and average visible transmittance (AVT). We address strategies to optimize ST-PSC performance, tackling inherent challenges, such as optical losses from reflection, parasitic absorption, and thermalization loss, which impact the operational efficiency under variable environmental conditions. ST-PSCs are distinguished by their lightweight, flexible, and translucent properties, allowing for diverse applications in urban building integration, agricultural greenhouses, and wearable technology. These cells integrate seamlessly into various settings, enhancing energy harnessing without compromising on aesthetic or structural elements. However, the scalability of ST-PSCs involves challenges related to stability and efficiency in large-scale deployments. The tropical urban landscape of Singapore provides a unique case study for ST-PSC application, blending architectural aesthetics with high solar irradiance to optimize energy efficiency. While the potential for ST-PSCs to contribute to sustainable urban development is immense, significant technological hurdles must be overcome to realize their full potential. Continued advancements in material science and engineering are essential to address these challenges, ensuring the scalability and long-term deployment of ST-PSCs in global energy solutions.

Optimizing Exciton Diffusion and Carrier Transport for Enhanced Efficiency in Q‐PHJ and BHJ Organic Solar Cells

AbstractExciton diffusion and carrier transport are two critical factors that determine the efficiency of organic photovoltaics (OPVs). However, the relationship between these two factors has not been extensively studied. Designing non‐fullerene acceptors (NFAs) with efficient diffusion coefficients and high electronic transmittance is a key area of focus. In this study, materials for bulk‐heterojunction (BHJ) and quasiplanar‐heterojunction (Q‐PHJ) devices are synthesized to validate the desired differences in crystallinity. The single crystal of BOBO4Cl‐βδ demonstrated the most compact packing structure, with an improved planar configuration and closer π···π distances, resulting in higher electron mobility and superior exciton diffusion coefficient. Consequently, BOBO4Cl‐βδ‐based devices achieved a power conversion efficiency (PCE) of 17.38% in Q‐PHJ, compared to a lower PCE of 14.75% in BHJ devices. Furthermore, incorporating BOBO4Cl‐βδ into the D18/L8‐BO Q‐PHJ system increased the PCE from 17.98% to 18.81%, one of the highest values recorded for Q‐PHJ devices. This improvement is attributed to strong crystallinity of BOBO4Cl‐βδ, which enhances the packing arrangement and improves the exciton diffusion coefficient. Our work highlights the importance of molecular design with tunable exciton diffusion and carrier transport for BHJ and Q‐PHJ OPV architectures and reveals the relationship between them, which contributes to the achievement of high‐performance NFAs.

Ultra-broadband achromaticity of metalens with low-relative phase enabled by wide-band fusion

Metalenses have a high design degree of freedom in controlling the light field and excellent performance in chromatic aberration elimination. However, in designing ultra-broadband achromatic metalenses, integrating multiple types of unit structures is necessary to compensate for phase differences caused by different incident wavelengths. Here, we propose an ultra-broadband achromatic metalens composed only of a single type of square nano-pillar. which controls the entire operating band by utilizing three wide-band fusions, and have characteristics depending on the phase coverage and relative phase. In the operational range of 2–5 μm, the achromatic metalens demonstrates a maximum focal shift of 2.1 μm. The average focal shift is 0.98 %, the average NA value is 0.35, with an average relative phase of 0.77π. The average transmittance and focus efficiency are 94.17 % and 58.7 %, respectively. This broad-spectrum fusion design strategy simplifies manufacturing complexity while maintaining high focusing efficiency and transmittance levels throughout the entire operational bandwidth. This design approach can improve image resolution and quality by minimizing chromatic aberration.

Heliostat Field Optical Efficiency Calculation

Abstract The solar power tower technology has the advantages of green pollution-free and stable power generation, which has gradually attracted extensive attention from researchers in recent years. The quick computation of the solar heliostat field’s optical efficiency carries substantial potential for refining the design of the heliostat field, thereby enhancing the efficiency of power generation. Based on the parallel light hypothesis, we propose a fast algorithm designed to compute the optical efficiency of heliostat field. The algorithm takes into account various optical loss terms such as mirror reflectivity, cosine efficiency, shadowing and blocking efficiency, atmospheric transmittance efficiency and truncation efficiency. When calculating the shadowing and blocking efficiency, the “judgment rectangle” is used to quickly screen the candidate heliostat that may produce shadowing and blocking to the target heliostat. When calculating the truncation efficiency of the receiver surface, the strip discrete method and geometric projection method are used to quickly judge whether the reflected light is intercepted by the receiver, thus improving the calculation speed of optical efficiency. Consider a surrounding heliostat field as a test case, the proposed algorithm is compared with the conventional ray tracing, and the effectiveness and efficiency of the new algorithm are verified. The algorithm proposed in this paper has the advantages of accurate results and high calculation efficiency, and provides valuable insights that can be utilized for optimizing the design of heliostat field and improving the efficiency of tower solar thermal power generation.

On the value of Fano resonance in wave energy converters

The article evaluates the potential of the Fano resonance operational principle in wave energy converters (WECs), using a 2-body loosely moored self-referenced WEC as an illustrative example. By leveraging Fano resonance, the point absorber buoy can remain relatively stationary with low loading on mooring lines, serving as an efficient wave energy transmitter while concurrently achieving resonance within the internal power take-off (PTO) system. This arrangement reduces the motion of the point absorber hull, thereby decreasing loads on the WEC structure, mooring lines, and anchors. As a result, operational and structural costs are minimised, further reducing the levelised costs of generated energy. Additionally, by ensuring minimal fluctuations in the WEC, confidence in using traditional linear mathematical models is increased, as commonly employed for WEC performance assessment and control design.The article presents a resonance study and introduces newly derived solutions in the frequency domain for the proposed operational concept. It analytically demonstrates the viability of employing the Fano resonance operational strategy for WECs, suggesting that this strategy has the potential to compete with traditional methods of wave energy transformation. Furthermore, the insights gained from the study contribute to identifying optimal parameters for a PTO system, as well as optimising the design of the heaving buoy.

Investigating the Balance between Power Conversion Efficiency and Average Visible Transmittance for Semitransparent Perovskite Solar Cells

Investigating the Balance between Power Conversion Efficiency and Average Visible Transmittance for Semitransparent Perovskite Solar Cells

TiO2-catalyzed photodegradation of methylene blue in a helical FEP tubing reactor: modeling and optimization using response surface methodology

A novel photocatalytic reactor was developed to degrade methylene blue in water using titanium dioxide (TiO2) as a catalyst and fluorinated ethylene propylene (FEP) tubing as a transmitter for ultraviolet (UV) radiation. The reactor was operated by continuously flowing the solution through narrow tubes that were exposed to UV radiation. The efficiency of the reactor was evaluated by comparing it to a previous study that used quartz glass tubing. The study also investigated the effects of flow rate, initial concentration, pH, TiO2 dose and UV radiation without a catalyst on the degradation of methylene blue. The results showed that the FEP tubing was a more efficient UV transmitter than quartz glass. The efficiency of the reactor was also affected by the flow rate and pH of the solution. The highest degradation efficiency was achieved at a flow rate of 10 mL/min and a pH of 7.0. The use of TiO2 as a catalyst also significantly improved the degradation efficiency, with an almost doubling of the degradation rate when compared to the case without a catalyst. This study demonstrates the potential of the FEP tubing-based photocatalytic reactor for the degradation of methylene blue in water. The reactor is easy to operate and can be scaled up for industrial applications.

Generalized Huygens' Condition as the Fulcrum of Planar Nonlocal Omnidirectional Transparency: From Meta‐Atoms to Metasurfaces

AbstractFresnel reflection has been known for centuries to fundamentally impede efficient transmittance across planar interfaces, especially at grazing incidence. In this work, the generalized Huygens' condition (GHC) is introduced to resolve such intricacies in metasurface (MS) designs and allow omnidirectional transparency. Compared to common numerical metamaterial approaches, the analytical framework herein yields surprisingly simple closed‐form conditions, carefully leveraging the natural nonlocal mechanisms endowed in planar electromagnetic structures. At the meta‐atom level, the GHC is met by balancing traditional tangential susceptibilities of Huygens' MSs with their unconventional normal counterparts; the latter facilitates the key requisite of vanishing backscattering at the challenging grazing incidence scenario. At the MS level, this central insight is sheerly utilized to engineer realistic all‐angle transparent printed‐circuit‐board (PCB) cascaded admittance sheets. Thoroughly validated in simulation and experiment, this universal GHC demonstrates a resourceful venue for practical implementation of advanced nonlocal devices, e.g., flat optical components, optical analog computers, and spaceplates.

Enhancing Light Utilization Efficiency of Semi‐Transparent Perovskite Solar Cells via Tailored Interfacial Engineering

AbstractSemi‐transparent perovskite solar cells (ST‐PSCs) are promising for their application in building integrated photovoltaics (BIPVs). For BIPVs, a light utilization efficiency (LUE) > 2.5 is required which is multiplication of average visible transmittance (AVT) and power conversion efficiency (PCE). Generally, semitransparency is achieved by reducing film thickness which increases AVT but decreases PCE resulting in lower LUE. Here, an interface engineering strategy is employed on a wide bandgap perovskite thin absorber layer to increase PCE and LUE. The study employs three different alkylamine hydrochlorides molecules with varied alkyl chain length, viz., 2‐chloroethylamine‐hydrochloride, 3‐chloropropylamine‐hydrochloride, and 4‐chlorobutyalamine‐hydrochloride at perovskite/electron transport layer (ETL) interface and investigates their effect on perovskite crystallization. Further, it is demonstrated that 4‐chlorobutyalamine‐hydrochloride can strongly interact with perovskite and suppress non‐radiative recombination facilitating charge transport at the perovskite/ETL interface. Devices post‐treated with 4‐chlorobutyalamine‐hydrochloride interfacial layer, demonstrate a higher LUE of 3.45% (PCE 14.11%) and AVT of ≈25% (400–800 nm), with Voc of 1.23 V. Moreover, the unencapsulated devices retain ≈89% of the initial efficiency after storage for 1500 h under a relative humidity of ≈35–40%. This study provides an efficient approach to improve LUE and stability of ST‐PSCs for the application in energy‐efficient smart windows.

A flexible and breathable ammonium polyphosphate/chitosan/MWCNT doped PEDOT:PSS coating decorated carbon cloth for high-efficiency flame retardancy and electromagnetic interference shielding applications

There is an urgent need for versatile textiles for different applications due to the rapid development of flexible and wearable electronic devices. However, the poor breathability, high cost, and complex manufacturing processes are still urgent issues to be addressed. In this work, a breathable and flexible carbon cloth (CC) decorated multifunctional coatings (ACMPP) is developed through a facile and scalable coating technology for flame retardancy and electromagnetic interference (EMI) shielding applications. The ACMPP are constructed by incorporating the ammonium polyphosphate/chitosan/multi-walled carbon nanotubes (ACM) composites with core-multi-shell structure into PEDOT:PSS (PP). The low-cost ACM composites demonstrate the promising potential to substitute complex manufacturing processes with an easy electrostatic self-assembly. The as-obtained ACMPP/CC composites display favorable air permeability (69.65 mm·s-1), efficient water vapor transmittance (273.17 kg·m-2·d-1), and high-efficiency flame retardancy (36.8 % of limiting oxygen index), coupled with excellent EMI shielding capacity (59.36 dB in the X band) and shielding stability. The simplicity and scalability of the approach in this work offers a highly cost-performance paradigm to construct next generation flexible textiles for flame retardancy and electromagnetic interference shielding applications.

System for delivering radio interference transmitters to receiving devices of ground-based radio electronic means of satellite radio communication and radio navigation systems

Formulation of the problem. The method of delivering radio jamming transmitters to the area where a radio-electronic device is located, based on dropping transmitters from an unmanned aerial vehicle, is characterized by a number of disadvantages: high complexity of the equipment and, accordingly, the high cost of the UAV; low efficiency of radio interference transmitters in suppressing ground-based radio electronics of satellite radio communication and radio navigation systems. Purpose. Consider the possibility of increasing the efficiency of radio-electronic suppression of ground-based radio electronics of satellite radio communication and radio navigation systems by autonomous radio jamming transmitters delivered to the work area using UAVs, while reducing the complexity of the equipment and the cost of UAVs - carriers of radio jamming transmitters. Results. A delivery system for radio interference transmitters is proposed. The system uses an uncontrolled free aerostat (balloon) filled with gas as a UAV. The volume of gas depends on the given flight altitude. The balloon, together with the transmitter and battery, is launched from a starting position placed on the earth's surface, taking into account the known direction of the wind and the known location of the suppressed weapon. The balloon is delivered to the electronic jamming work zone by moving air masses. The calculations showed that the use of the proposed system provides a gain in the required transmitter EIRP of at least 7 dB compared to a ground-based transmitter. To suppress a Starlink user terminal at a range of up to 4 km, a transmitter with an EIRP of no more than 13 dBW (20 W) is required. Practical significance. The results obtained can be used to increase the efficiency of electronic jamming of ground-based satellite radio communication and radio navigation systems.

Methodology for substantiating the parameters of navigation signals with double meander modulation for local navigation systems based on land pseudo-satellites

Formulation of the problem. The development of local navigation systems based on land pseudo-satellites in order to solve the problem of insufficient noise immunity of global navigation satellite systems determines the relevance of the improvement of the theory of multicriteria synthesis of new types of navigation signals. Purpose. Ensuring high accuracy and continuity of navigation-time definitions with the level of out-of-band radiation reduced to compliance with electromagnetic compatibility requirements and an acceptable decrease in the energy efficiency of transmitters by developing a methodology for substantiating the parameters of navigation signals with double meander modulation for local navigation systems based on land pseudo-satellites. Results. The use of navigation signals with double meander modulation in local navigation systems based on land pseudo-satellites is proposed, and their advantages over currently used signals are shown. A methodology of multi-criteria substantiating of navigation signal parameters has been developed, taking into account spectral, correlation characteristics, as well as the effect of reducing the level of out-of-band radiation of land radio transmitting devices in order to ensure electromagnetic compatibility requirements on the time characteristics of the signal. Practical significance. The obtained results can be used by specialists in the field of local and global radio navigation systems when considering the introduction of new types of navigation signals that ensure high quality indicators of tracking their parameters, as well as the application of new and existing navigation signals in local navigation systems based on land pseudo-satellites.

The Efficiency and Power Utilization of Current-Scaling Digital Transmitters

The Efficiency and Power Utilization of Current-Scaling Digital Transmitters

A novel optical management layer with flexible color tunability and high transmittance in organic solar cells

The evaluation of colored semi-transparent organic solar cells (ST-OSCs) relies on the power conversion efficiency (PCE) and peak transmittance across the visible light spectrum. However, it is a significant challenge to enhance both parameters simultaneously. In this study, we investigate the impact of different film systems for the Ag electrode on transmittance enhancement using an optical interference formula derived for anti-reflective films. As a result, a novel ZnS/WO3 double-layer anti-reflective film is introduced as an optical management layer. The ZnS/WO3/Ag structure achieves a peak transmittance exceeding 75 % across the visible light spectrum while also offering customizable color attributes. Upon electrical simulation, the power conversion efficiency (PCE) of organic solar cells with 15 nm Ag and 80 nm PM6:Y6 reached to 11.72 %, and an ideal PCE value of 14.53 % is achieved by reducing non-radiative recombination. Through optical simulations, it has been demonstrated that the integration of a ZnS/WO3 double-layer anti-reflective film with organic solar cells enables the generation of OSCs in vibrant purple, blue, cyan, and green hues. Notably, these OSCs exhibit their highest peak transmittance at blue light (452.5 nm), reaching an impressive value of 50.49 %. These remarkable findings not only showcase exceptional performance but also highlight significant potential in applications involving colored OSCs utilizing the new optical management layer composed of ZnS/WO3 double-layer anti-reflective films.

WITHDRAWN: Cross polarization converter with high transmittance and near unity polarization conversion efficiency for visible light based on bilayer all-dielectric metasurface

It is highly desired to achieve high efficiency polarization converters in visible wavelength region for ultra-compact optical systems which have shown potential applications in optical sensing, communication and imaging. Due to the intrinsic property of low loss, all dielectric metasurfaces are more competitive candidates to be utilized for fabrication of polarization converters than the counterparts based on metals. In this paper, we design a bilayer all dielectric metasurface polarization converter composed of a Si double-rod resonator placed on the top of a glass block with a polymer substrate for linearly polarized visible light. The proposed bilayer metasurface structure can convert linearly polarized light to the cross-polarized light efficiently within the visible region from 542 nm to 563 nm in the transmission mode with high transmittance and near unity polarization conversion efficiency. The transmittance is larger than 0.8 in the mentioned wavelength range with a maximum transmission of 0.86 at 556 nm and polarization conversion ratio is larger than 90% in the same wavelength range with a maximum polarization conversion ratio of 99.01% at 556 nm. The underline physical mechanisms of high conversion efficiency and high transmittance are analyzed in detail with simulated distributions of surface current, electrical field distributions and the calculated multipole decompositions of the scattering power.

Improved performance of ternary organic solar cells based on both bulk and pseudo-planar heterojunction active layer

The high photovoltaic conversion efficiency (PCE) of ternary organic solar cells (OSCs) based on PTB7-Th, PC71BM and IEICO-4F material is obtained, the short-circuit current density (J SC), fill factor (FF), and open-circuit voltage is 25.90 mA cm−2, 73.20% and 0.71 V, respectively. PCE is as high as 13.53%. It is the highest PCE of ternary OSCs based on PTB7-Th, PC71BM and IEICO-4F materials for all we know. The narrow bandgap material of IEICO-4F is deposited on PTB7-Th:PC71BM bulk heterojunction (BHJ) by layer-by-layer process. We constructed the dual bandgap active layer both BHJ and pseudo-planar heterojunction (P-PHJ), it could be defined as ternary BHJ/P-PHJ of OSCs. This type of OSCs is not only the complementary bandgap material of the active layer, but also increasing the donor/acceptor (D/A) interface. The excitons generation and collection of the device are increased leading a higher J SC and FF. The semitransparent OSCs (ST-OSCs) is prepared by varying the thickness of Ag electrode and PCE can reach 9.70%, and the average visible light transmittance and light use efficiency of ST-OSCs are improved effectively.

Sustainable kiwi fruit derived carbon dots architected WO3 (KF-CDs@WO3) thin films based flexible electrochromic devices with improved stability for next generation smart windows applications

The design and development of new advanced materials or technologies are essential for the construction of high performance smart windows for the next generation of energy efficient buildings. Tungsten trioxide (WO3) based flexible electro-chromic devices f-ECDs have received extensive attention for the development of next generation f-ECDs. Here, we demonstrated the design and fabrication of kiwi fruit peel derived carbon dots (KF-CDs) decorated WO3 films under benign approaches. Furthermore f-ECDs were developed and their performance have been examined in terms of transmittance and coloration efficiency. The amount of KF-CDs in to the WO3 was varied and optimized f-ECDs exhibited the excellent optical contrast (ΔT) of 83.74 %, coloration efficiency of 86.2 cm2/C. The optimized f-ECDs exhibited excellent cyclic stability of 25000th cycles and retained more than 80 % optical contrast compared to the initial performance. This improved stability may be attributed to the presence of strong hydrogen bonding between the functional groups of KF-CDs and WO3.

Design and simulated characterization of the dual-band polarizer based on metasurface structure

Dual-band polarizers must simultaneously exhibit high transmittance and bandwidth efficiency in fields such as polarization navigation and efficient detection. However, in most studies, the detection of dual bands is inefficient. To address this issue, we designed a dual-band polarizer similar in structure to the Roman numeral II, and it allows transmission of two different linear polarizations within different frequency bands. The interaction of the dual-band nano-polarizer with the polarization state of the incident light was analyzed through simulation experiments on the material, height, duty cycle, and other parameters of the periodic structure of the polarizer unit. The simulation results show that the proposed dual-band polarizer could achieve a polarization degree above 0.75 in the visible range and above 0.8 in the near-infrared (NIR) range. In addition, the transmittance was above 80% for x-polarization light in most of the visible wavelengths and reached 97.7% for y-polarization light in the NIR region, where NIR bandwidth accounted for 83.3% of the NIR wavelengths. The proposed design can achieve high transmittance and can be applied to ultrawide single-band polarization detection or dual-band vertical polarization detection.

High data rate and energy efficient configurable IR-UWB transmitter with an integrated balun

This paper presents a novel, digitally configurable, switching oscillator-based impulse radio ultra-wideband (IR-UWB) transmitter that is robust to process variations. The pulse width and pulse position properties of the output waveform are configurable to ensure operation for the desired bandwidth and output pulse energy values. The architecture is based on a cross-coupled LC voltage-controlled oscillator (LC VCO) implemented with a custom-designed on-chip balun at a center frequency of 2.4 GHz. With the usage of this on-chip balun, the need for an extra buffer stage is eliminated, and the highest possible efficiency is achieved with the proper turns ratio selected. The generated digital control pulse signals are also used to ensure fast start-up and UWB operation while maintaining low power consumption with an implemented on/off tail switching scheme. The presented IR-UWB transmitter that occupies a total area of 0.35 mm2 is fabricated in the United Microelectronics Corporation (UMC) 180-nm mixed-mode/radio frequency (RF) CMOS process. The measured output voltage swing of the fabricated transmitter is 0.812 V on a 50-Ω load for the 200 Mb/s data rate, and the bandwidth is measured as 902 MHz. The achieved frequency tuning range is 1 GHz and the fabricated transmitter can drive 50 Ω, 75 Ω and 100 Ω loads with measured efficiency values 4.16%, 5.76%, and 4.05%, respectively. Compared to other works in the literature, this design achieves a higher output pulse energy at a higher data rate while maintaining low power consumption and, thus, high efficiency.