Solar Harvesting Research Articles

Energy harvesting techniques for sustainable underwater wireless communication networks: A review

The emergence of various underwater wireless communication systems has been on the rise due to increasing human activities in the marine environment. In underwater wireless communication networks (UWCNs), several communication devices, such as sensors and autonomous underwater vehicles (AUV) are interconnected to expand communication coverage, monitoring, information gathering, and surveillance. These devices operate on batteries, making their replacement and recharging difficult. Consequently, sustaining the operational lifetime of UWCNs is deemed a major challenge. This leads to the development of various energy harvesting (EH) techniques to perpetuate the power supply to underwater devices. In this paper, we present a review of various energy sources and EH techniques applicable to UWCNs. To achieve this, we classify the energy sources into various categories in order to establish the peculiarities of each source and the type of harvester applicable to each category. Based on this classification, we present discussions on various contributions of articles related to applications of EH techniques in UWCNs. In addition to various insights gained from the presented papers, we establish that energy harvesters based on triboelectric effect, piezoelectric effect, sediment microbial fuel cell, acoustic, and optical power transfer are suitable for low-power (milliwatt-order) consuming devices such as sensors. Also, for devices with high power consumption requirement, such as AUV, solar and inductive power transfer-based harvesters should be employed. Furthermore, we identify several technical challenges that should be taken into consideration during the planning and system design phases. Finally, we highlight open research areas that could further improve the EH and communication processes in UWCNs.

Energy and exergy analyses of a solar PV/T driving hybrid reverse osmosis-thermal distillation system

Solar desalination holds significant promise for providing freshwater to remote and off-grid areas, which includes solar thermal distillation (STD) and solar photovoltaic reverse osmosis (PV-RO). To achieve higher efficiency via full-spectrum utilization of solar energy, this paper proposes a hybrid reverse osmosis-thermal distillation system driven by a solar photovoltaic-thermal collector (PV/T-RO-TD). To evaluate the conversion of solar energy, electrical energy, thermal energy and chemical energy in these three systems, both the first-law and second-law based analyses are adopted. Results show that while PV/T-RO-TD systems only have moderate energy and exergy efficiencies in the desalination process, it achieves better utilization of solar energy. Meanwhile, the energy and exergy efficiencies are 83%, 81%, 13%, and the exergy efficiencies are 20%, 3%, 13% in the solar harvesting process of PV/T-RO-TD, STD, and PV-RO, respectively. In addition, the specific water productivity under one-sun of 26.94–73.92 L/m2 h in the PV/T-RO-TD system surpasses it in STD and PV-RO systems, which are 3.79–9.89 L/m2 h and 22.74–69.63 L/m2 h, respectively. With better performance, the PV/T-RO-TD system can be regarded as an effective choice for boosting the water productivity of solar desalination.

A “Green” Reaction Cycle Pathway for Synthesizing Metal Oxide Quantum Dots

Synthesis of highly stable quantum dots (QDs) is always a challenge for researchers in nanomaterial community because of involved complexities of the process time and steps. In the past few years, we have demonstrated a simple and single step synthesis process for a range of metal oxide (MO) QDs using plasma-induced non-equilibrium electrochemistry (PiNE).1 , 2 , 3 PiNE is a new and emerging technique based on electrochemical process taking place in liquids from plasma interaction.4 This method is rapid and produces highly stable QDs starting from a metal foil and ethanol as electrolyte. As MO QDs semiconductors in general are a promising candidate for energy harvesting application mainly from their nanoscale effects.5 , 6 In this work, we will present the general applicability of this method for a range of metal oxides and the provide more an in-depth case study for CuO QDs providing details of the reaction mechanisms. An extensive analysis of the solution along with the quantum dots was carried out with nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass (GC-MS) spectroscopy, Fourier transform infra-red spectroscopy (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy, pH and the plasma-ethanol interface using optical emission spectroscopy. Thus, the study discloses important aspects of plasma interactions with a non-aqueous medium particularly the trace products and QD purity shows the entire process is a ‘green’ synthesis cycle.7 Reference (1) Ni, C.; Carolan, D.; Rocks, C.; Hui, J.; Fang, Z.; Padmanaban, D. B.; Ni, J.; Xie, D.; Maguire, P.; Irvine, J. T. S.; Mariotti, D. Microplasma-Assisted Electrochemical Synthesis of Co 3 O 4 Nanoparticles in Absolute Ethanol for Energy Applications. Green Chem. 2018, 20 (9), 2101–2109. https://doi.org/10.1039/C8GC00200B.(2) Ni, C.; Carolan, D.; Hui, J.; Rocks, C.; Padmanaban, D.; Ni, J.; Xie, D.; Fang, Z.; Irvine, J.; Maguire, P.; Mariotti, D. Evolution of Anodic Product from Molybdenum Metal in Absolute Ethanol and Humidity Sensing under Ambient Conditions. Cryst. Growth Des. 2019, 19 (9), 5249–5257. https://doi.org/10.1021/acs.cgd.9b00646.(3) Chakrabarti, S.; Carolan, D.; Alessi, B.; Maguire, P.; Svrcek, V.; Mariotti, D. Microplasma-Synthesized Ultra-Small NiO Nanocrystals, a Ubiquitous Hole Transport Material. Nanoscale Adv. 2019. https://doi.org/10.1039/C9NA00299E.(4) Mariotti, D.; Patel, J.; Švrček, V.; Maguire, P. Plasma-Liquid Interactions at Atmospheric Pressure for Nanomaterials Synthesis and Surface Engineering. Plasma Process. Polym. 2012, 9 (11–12), 1074–1085. https://doi.org/10.1002/ppap.201200007.(5) Velusamy, T.; Liguori, A.; Macias-Montero, M.; Padmanaban, D. B.; Carolan, D.; Gherardi, M.; Colombo, V.; Maguire, P.; Svrcek, V.; Mariotti, D. Ultra-Small CuO Nanoparticles with Tailored Energy-Band Diagram Synthesized by a Hybrid Plasma-Liquid Process. Plasma Process. Polym. 2017, 14 (7), 1600224. https://doi.org/10.1002/ppap.201600224.(6) McGlynn, R.; Chakrabarti, S.; Alessi, B.; Moghaieb, H. S.; Maguire, P.; Singh, H.; Mariotti, D. Plasma-Induced Non-Equilibrium Electrochemistry Synthesis of Nanoparticles for Solar Thermal Energy Harvesting. Sol. Energy 2020, 203 (April), 37–45. https://doi.org/10.1016/j.solener.2020.04.004.(7) Padmanaban, D. B.; McGlynn, R.; Byrne, E.; Velusamy, T.; Swadźba-Kwaśny, M.; Maguire, P.; Mariotti, D. Understanding Plasma–Ethanol Non-Equilibrium Electrochemistry during the Synthesis of Metal Oxide Quantum Dots. Green Chem. 2021, 23 (11), 3983–3995. https://doi.org/10.1039/D0GC03291C.

Quantum Inspired Broadband Photonic Absorber: Potential Application as Solar Sail along with Mobility Analysis

Electromagnetic wideband absorption is still perceived as a critical and formidable challenge to address with an unambiguous photonic absorber. Subwavelength metamaterial (MM) unit cells with unique and controlled features have recently gained considerable interest. However, meta‐atoms, generated using a quantum‐inspired pattern distribution, are underwhelming in existing literature to design photonic absorbers and their potential application to manufacture solar sails is still quite uncommon. In this article, to create a flexible, polarization‐insensitive, ultrathin, and broadband MM absorber, quantum interference pattern‐inspired design is utilized. Herein, a novel approach to fabricating solar sails for the space exploration incorporates the proposed broadband photonic absorber rather than conventional reflectors. The quantum‐inspired meta‐absorber (QIMA) exhibits an absorption of over 91% for the visible domain, i.e., 380–800 nm under a conventional plane‐polarized source. It is shown in the study that broadband absorbers are almost equivalent to excellent reflectors to design the solar sails in terms of the time‐averaged force calculated by utilizing the Maxwell stress tensor method. Thus, the QIMA has the potential to be a viable alternative to reflectors in the design of futuristic solar sails for space exploration. The interference theory model is also utilized to assure the dependability of calculated data, and additionally, the standard AM1.5 solar spectrum is utilized to demonstrate the QIMA's solar‐harvesting potentiality.

Significance of anchoring group design on light harvesting efficiency of dye-sensitized solar cells and non-linear optical response

Dye-sensitizers designed from coumarin backbone are widely utilized in solar light harvesting due to their versatile performance in dye-sensitized solar cells (DSSC). They are well-known as non-linear optical (NLO) materials. In this case study, we have designed coumarin-based sensitizers containing thiophene as a common spacer with the different acceptor-anchoring groups, ethyl-2-cyanoacrylate (SPDSSC 1) and 2-cyanoacrylic acid (SPDSSC 2). Density functional theory (DFT) and time-dependent- DFT (TD-DFT) computational calculations of these molecules predict superior light harvesting capability and NLO properties. The calculated HOMO–LUMO energy gap of these dyes showed an inverse relation with chemical potential and electrophilicity index and was directly related to hardness and hyperhardness. It was also seen β0 and γ and PCE follow a similar trend. Further, computations of sensitizers@TiO2 indicated sensitizers with ethyl-2-cyanoacrylate bonded with TiO2 cluster via unidentate linkage, whereas 2-cyanoacrylic acid containing sensitizer involved bidentate bonding with TiO2. Apart from this, sensitizers with 2-cyanoacrylic acid anchors showed much planer geometry. Also, the quantitative analysis of the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) and MEP plots showed that more electron clouds shifted to the TiO2 cluster in the sensitizer with 2-cyanoacrylic acid (SPDSSC 2) than ethyl-2-cyanoacrylate (SPDSSC 1). Further, both molecules were taken as sensitizers in the DSSC device. SPDSSC 2 showed higher power conversion efficiency than SPDSSC 1. Overall, results disclosed that sensitizers with ethyl-2-cyanoacrylate having two oxygen atoms in their anchoring part could bind with only carbonyl oxygen. And this monodentate binding of ethyl-2-cyanoacrylate with TiO2 leads to poor charge transfer in the semiconductor's conduction band, resulting in poor DSSC performance.

Ultraviolet and visible light active photothermal copper bismuth oxide nanostructures for solar steam generation

The CuBi2O4 (CBO) microspheres comprising 1D nanostructures crystallized in a tetragonal crystal system with P4/ncc space group. The Cu and Bi ions in the CBO photothermal harvesters remained in stoichiometric 2+ and 3+ oxidation states, respectively. The CBO showed excellent absorption in the entire ultra-violet (UV) and visible spectrum, covering the prominent solar spectrum. The CBO microsphere formed by assembling 1D CBO nanorods possessed a specific surface area of 1.45 m2/g, and the temperature-dependent contact angle of water over CBO surface decreases upon increasing temperature, making it an excellent choice in solar steam generation (SSG) process. Thus, the presence of CBO-loaded cellulose paper at the air-water interface has demonstrated three times accelerated evaporation rate of 1.7 kg/m2h. Notably, the CBO-loaded cellulose paper delivered high stability with no change in evaporation rate even after consecutive cycles. The CBO exposed to the natural sunlight in the customized desalination setup provided >50 % CR/ER ratio for the salinity of 3.5, 10, and 20 wt % salty waters. Our findings establish that CBO is a highly desirable photo-material for SSG and has the potential to act as a solar light harvester for photovoltaic systems.

Sun-powered CO2 transformation: TBE-Y photocatalyst's remarkable selectivity for solar-induced HCOOH

Carbon dioxide, one of the primary greenhouse gasses leading to global warming, ocean acidification, and climate change is an obnoxious concern. Human dependency on fossil fuels not only spikes the CO2 level but also depletes the limited energy resources. The horrendous impact of carbon footprint has made the reduction of CO2 into solar fuel an indispensable task. The photocatalyst-enzyme integrated artificial system has emerged as a benchmark for CO2 fixation solving both the energy crisis and carbon emission simultaneously. Herein a TBE-Y photocatalyst designed by coupling triptycene (T) with eosin-Y (EY) through Friedel Craft reaction shows excellent solar light harvesting property, high molar extinction coefficient, and appropriate band-gap. The as-synthesized 3D polymeric TBE-Y photocatalyst exhibits high NADH regeneration (78.77%) which when consecutively coupled with enzyme (formate dehydrogenase) via electron mediator produces HCOOH (189.34 μmol) from CO2 in high yield in 2 h.

Selective aerobic coupling of amines to imines using solar spectrum-responsive flower-like Nen-graphene quantum dots (GQDs) decorated with 2, 4-dinitrophenylhydrazine (PH) as a photocatalyst

Indeed, the development of ecologically benign molecular fabrication methods for highly efficient graphene quantum dots-based photocatalysts is of great significant. Graphene quantum dots-based photocatalysts have promising applications in various field, including environmental remediation, energy conversion, and splitting of water. However, ensuring resource reusability and minimizing the environmental impact are crucial considerations in the development. From this perspective, attention has also been paid to the creation of easy to make solar light harvesting graphene quantum dots-based photocatalysts for synthesising pharmaceuticals and functional imines compounds. Imines are excellent significant building blocks in pharmaceutical chemistry and excellent examples of these valuable compounds' synthetic intermediates, and the environmentally friendly oxidative synthesis of imines from amines. Therefore, herein, we designed a facile and efficient condensation route to synthesize the Nen-GQDs@PH photocatalyst. This route involves coupling of 2,4-dinitrophenylhydrazine (PH) with nitrogen-enriched graphene quantum dots (Nen-GQDs). The Nen-GQDs@PH as photocatalyst functions in a highly selective and efficient manner, leading to high amines conversion efficiency to imines (95%). Our results highlight a novel and environmentally safe approach for generating highly selective imines from various types of amines, setting a new benchmark in the current research field.

Bioinspired Antireflection Double‐Layer Coatings Design Method and Light Management to Realize Radiative Sky Cooling in Photovoltaic Module

Recent research on combining photovoltaic (PV) modules with radiative sky cooling (RSC) technology has elicited much interest. Such cross‐disciplinary technology coupling provides a feasible approach to solar cells’ nighttime applications. However, current commonly used radiative sky cooling materials’ (RSCMs) conflict with the solar light harvesting and utilizing of PV module. The spectral selectivity characteristics of the strong transmission in the solar spectrum range (0.3–1.1 μm) and the enough emissivity within the atmosphere transparency window (8–13 μm) are the essential to develop the PV module‐usable RSC coating. Herein, antireflection (AR) structure optimize method and RSC coating design method are proposed to achieve nighttime RSC capacity with high solar radiation transmission property via the RSCM selection and light management, in the visible, near‐infrared, and midinfrared wavelength range, originating from the subwavelength optical effects of bioinspired AR design. A kind of double‐layer coating consisting of the PDMS substrate layer and SiO2 close‐packed hexagonal rotating parabolic body‐bioinspired moth‐eye structure cover layer is designed in this research. The coating has 0.997 average transmissivity characteristic in solar spectrum and can lower the PV cell temperature over 10.5 K than ambient at night.

A near-perfect metamaterial selective absorber for high-efficiency solar photothermal conversion

High-efficiency solar metamaterial selective absorbers are indispensable technologies for new renewable energy, with significant application prospects in realizing high-efficiency solar photothermal and photoelectric conversion and desalination. Although various solar selective absorbers have been achieved, there are generally problems such as low efficiency, complex structure, and poor spectral selectivity. Herein, we propose a dual-dielectric-layer metamaterial selective absorber (DDMSA) that achieves near-perfect absorption in the entire solar spectrum while having low thermal radiation in the mid-infrared region. The proposed DDMSA can achieve strong absorption with an absorbance of above 90% over a wide spectrum from ultraviolet to near-infrared (i.e., from 280 to 2280 nm). This broadband strong absorption is attributed to several mechanisms, including interference effects, localized surface plasmon resonance (LSPR), propagating surface plasmon resonance (PSPR), and intrinsic losses of tungsten. An impressive solar photothermal efficiency surpassing 90% has been achieved spanning a broad temperature range from 100 to 1000 °C. Notably, it possesses superior performance in polarization-independent and wide-angle incidence behaviors. Therefore, the proposed metamaterial selective absorber has great potential in applications related to solar photothermal harvesting.

Hierarchical Tantalum Oxide Composite for Efficient Solar-Driven Water Purification.

Applying solar energy to generate drinking water is a clean and low-energy exhaust route to address the issue of water purification. The current challenge with solar vapor generation is constructing nano/micro-hierarchical structures that can convert solar irradiation into exploitable thermal energy with high efficiency. Although various structures and material designs have been reported in recent years, solar vapor conversion can be improved by integrating light harvesting, thermal concentration, and water diffusion. Because of the optimized solar harvesting, enhanced heat capacity, and specified diffusive path endowed by the hierarchical composite structure, amorphous tantalum oxide/carbon-based yolk-shell structures (α-Ta2O5/C YS) for highly efficient solar vapor generation under 1 sun illumination are applied in this study. As a result, the α-Ta2O5/C YS realized a water evaporation rate of 3.54 kg m-2 h-1 with a solar-thermal conversion efficiency of 91% under one sun irradiation (1 kW m-2) with excellent evaporation stability. The collected water from seawater meets the World Health Organization drinking water standard. Importantly, reactive oxygen species enabled by α-Ta2O5 could be produced for water sterilization, exhibiting a facile way for application in various scenarios to acquire drinkable water.

Solar-light-driven photocatalytic conversion of monosaccharide by oxygen-doped graphitic carbon nitride/artificial steel converter slag composite

The development of high performance, low-cost and resource-efficient photocatalysts with improved solar light harvesting capabilities can significantly enhance the practicability and viability of photocatalytic conversion of biomass-based substances to value-added chemicals. This work reports the construction of heterojunction between oxygen-doped graphitic carbon nitride and artificial steel converter slag (OCN/artCS) as efficient photocatalysts for conversion of biomass-derived monosaccharide to lactic acid under the simulated solar light. The OCN/artCS composites were facilely fabricated by the thermal polymerization of the mixtures of dicyanamide (DA) and oxalic acid (OA), which are precursors of OCN. The artCS acts as photocatalyst support for OCN to grow on its surface and can provide Ca2Fe2O5 semiconductor to possibly form the OCN/Ca2Fe2O5-containing artCS heterojunction. Compared with pristine OCN, the OCN/artCS composites exhibited higher photocatalytic performance for selective production of lactic acid, possibly due to the effective separation of photogenerated charge carriers after creation of OCN/artCS heterojunction. At the optimal content of artCS in the composites, the OCN/5%artCS delivered 99% glucose conversion and 90% lactic acid yield within 60 min at 50 °C under the simulated sunlight irradiation. This work can be a platform for the efficient utilization of industrial solid wastes for production of high-performance photocatalysts, enabling their promising applications in photobiorefinery and other photocatalytic processes.

Simulation of a floating solar farm in waves with a novel sun-tracking system

The awareness of the energy and climate crisis has accelerated the development of renewable energy sources. Photovoltaic (PV) solar power plants harvest clean solar energy and convert it to electricity, which will be one of the most promising alternatives to the power industry in the context of a low-carbon society. Due to its low power density, the traditional deployment of PV systems on land or inland rivers requires much space. Therefore, industries are increasingly interested in expanding offshore Floating PhotoVoltaics (FPV) to oceans, where FPV has less influence on the marine environment and does not occupy precious space for land resources and human activities. This study performs a hydrodynamics-based structural response analysis for a novel FPV system in OpenFOAM. The wave-proof FPV platform is newly designed for this work, which integrated breakwater technologies to sustain the system’s survivability in harsh ocean-wave environments. Firstly, the rational mooring types for FPVs installed close to the island are studied considering seabed effects. Subsequently, extensive parametric studies have been conducted to determine a rational design strategy for the mitigation of wave impact. Several potential effects of the proposed platforms on the hydrodynamics in a coastal sea are evaluated for the first time.

TiO2–x@C/MoO2 Schottky junction: Rational design and efficient charge separation for promoted photocatalytic performance

Limited solar light harvesting, sluggish charge transfer kinetics, and inferior affinity for adsorbed hydrogen species (H*) severely restrict the photocatalytic hydrogen generation activity of TiO2 photocatalysts. Herein, we present a novel TiO2–x@C/MoO2 Schottky junction prepared via a simple one-step in situ phase-transition-regulation strategy. Crucially, the abundant oxygen vacancies in TiO2–x@C/MoO2 narrow the bandgap and introduce defects to improve the photoresponse. The strongly bonded carbon layer not only serves as a fast charge-transport channel to improve the interlayer charge transfer efficiency but also protects oxygen vacancies from oxidation. Moreover, the Schottky barrier effectively impairs the recombination of electrons and holes and promotes the utilization of photogenerated electrons. Furthermore, the MoO2 cocatalyst optimizes the Gibbs free energy for H2 evolution. As a result of the favorable synergy, the resulting TiO2–x@C/MoO2 presents a significantly enhanced photocatalytic H2 production rate of 506 μmol g−1 h−1 compared to those of TiO2–x and TiO2–x@C (125.5- and 15.8-times larger, respectively). Moreover, outstanding stability over 27 h was achieved because of the protection provided by the surface carbon layer. This ingenious design and facile synthetic strategy offer exciting avenues for the design of strongly coupled Schottky junction photocatalysts for efficient solar-to-chemical conversions.

Design, implementation and performance assessment of a low-cost dual-axis solar tracker

As the demand for energy increases and the cost of non-renewable resources continues to rise, many nations are working to find alternative sources of electricity before a crisis arises. This effort is focused on transitioning away from conventional energy sources and towards non-conventional ones. Energy from the sun is clean and available in natural quantities, which can reduce our dependence on fossil fuels on a large scale along with providing low-carbon solutions. By tracking the sun’s radiations, the photovoltaic (PV) panels could be directed in such a way that they collect high levels of sunlight. This article presents the design and performance assessment of a low-cost dual-axis solar tracking system based on Arduino. The main objective of this study is to show that the proposed solar-tracking system performs better a non-tracking system. A light sensor and two servo motors are also employed to move the solar panel toward a high-intensity light source. The software domain code was created using the C programming language using the Arduino IDE, which interacts with the Arduino board and its other connected devices. The performance of the prototype was assessed and compared to that of a stationary solar panel of the same rating. In this paper, the authors have highlighted the necessary techniques to build a low-cost solar tracker for extracting maximum photovoltaic energy using real-time data. In terms of power output, the results reveal that the tracking system surpasses the fixed solar panel, indicating increased performance at a reasonable cost. Therefore, the solar tracker has been proven to be very effective in capturing significant solar energy for solar harvesting applications.

MIL-101(Fe)/BiOBr S-scheme photocatalyst for promoting photocatalytic abatement of Cr(VI) and enrofloxacin antibiotic: Performance and mechanism

The development of highly active, economical, and robust bifunctional photocatalysts is a priority for sustainable photocatalytic water remediation. Inadequately available reactive sites and sluggish interface photocarrier transfer and separation remain significant challenges in the photoreaction progress. In this study, the Fe-containing metal-organic framework (MOF) MIL-101(Fe) was integrated with BiOBr microspheres to form a competent S-scheme heterostructure for the photocatalytic mitigation of Cr(VI) and enrofloxacin (ENR) antibiotics. The optimal MIL-101(Fe)/BiOBr exhibited the highest photoactivity, with 99.4% of Cr(VI) and 84.4% of ENR eliminated upon visible-light illumination in a single-pollutant system. The photoactivity of MIL-101(Fe)/BiOBr in the decontamination of the Cr(VI)-ENR co-existence system exhibited a substantial enhancement when compared to that in a single system, owing to the improved utilization of electrons and holes resulting from the synergism between Cr(VI), ENR, and the photocatalyst. The enhanced photoactivity is attributed to two aspects: (1) the incorporation of MIL-101(Fe) results in an increased number of available reactive sites and improved solar harvesting properties; and (2) the S-scheme mechanism enables the effective spatial disassociation of photoexcited carriers and optimization of the photo-redox capability of the system. Through scavenging experiments, electron spin resonance characterization, liquid chromatography-tandem mass spectrometry analysis, and T.E.S.T. theoretical estimation, the catalytic mechanism, antibiotic degradation process, and biotoxicities of the degraded products were analyzed and confirmed. This study provides a viable strategy for building competent MOF-inorganic semiconductor S-scheme photocatalysts with superior photocatalytic decontamination performance.

An Efficient Routing Awareness Based Scheduling Approach in Energy Harvesting Wireless Sensor Networks

Wireless sensor networks (WSNs) have emerged as a promising technology for various Internet of Things (IoT)-based sensing applications. Generally, sensor nodes are powered by non-rechargeable and low-capacity batteries; they only last for a small amount of time. Due to their dispersed nature, sensor nodes cannot have their batteries replaced or maintained locally. The energy harvesting (EH) concept shows commitment as a method for addressing the current energy shortage. Another problem is the intra-energy control of various network load functions, including coverage preservation, routing, clustering, etc. This study proposes an ERAS (efficient routing awareness scheduling) algorithm to address the abovementioned issues. The ERAS method employs a solar harvesting system as a hierarchical clustering-based routing protocol. The presented scheme dynamically alters nodes between states and adjusts to new states based on the insides of sensed data packets. Synchronization-based scheduling ensures proper coordination between the cluster head (CH) and cluster members (CMs). It selects the CH based on both remaining and harvested energy and the number of active nodes to improve throughput. Surprisingly proposed EASR algorithm performs efficiently while considering various performance matrices, including network lifetime, packet delivery ratio, energy consumption, and network sustainability. Extensive simulation results exhibit the network lifetime of the proposed ERAS technique (79.8%) compared to ERA, SEED and CREST methods as 67.3%, 73.8%, and 75.2%, respectively.

Understanding and Suppressing Non-Radiative Recombination Losses in Non-Fullerene Organic Solar Cells.

Organic solar cells benefit from non-fullerene acceptors (NFA) due to their high absorption coefficients, tunable frontier energy levels, and optical gaps, as well as their relatively high luminescence quantum efficiencies as compared to fullerenes. Those merits result in high yields of charge generation at a low or negligible energetic offset at the donor/NFA heterojunction, with efficiencies over 19% achieved for single-junction devices. Pushing this value significantly over 20% requires an increase in open-circuit voltage, which is currently still well below the thermodynamic limit. This can only be achieved by reducing non-radiative recombination, and hereby increasing the electroluminescence quantum efficiency of the photo-active layer. Here, current understanding of the origin of non-radiative decay, as well as an accurate quantification of the associated voltage losses are summarized. Promising strategies for suppressing these losses are highlighted, with focus on new material design, optimization of donor-acceptor combination, and blend morphology. This review aims at guiding researchers in their quest to find future solar harvesting donor-acceptor blends, which combine a high yield of exciton dissociation with a high yield of radiative free carrier recombination and low voltage losses, hereby closing the efficiency gap with inorganic and perovskite photovoltaics.

Environmental Effects on the Performance of Quantum Dot Luminescent Solar Concentrators.

Luminescent solar concentrators (LSCs) are all-photonic, semitransparent solar devices with great potential in the emerging fields of building-integrated photovoltaics and agrivoltaics. Over the past decade, particularly with the advent of quantum dot (QD) LSCs, tremendous progress has been made in terms of photovoltaic efficiency and device size by increasing solar spectral coverage and suppressing reabsorption losses. Despite these advances in LSC design, the effects of environmental conditions such as rain, dust, and dirt deposits, which are ubiquitous in both urban and agricultural environments, on LSC performance have been largely overlooked. Here, we address these issues by systematically investigating the environmental effects on the solar harvesting and waveguiding capability of state-of-the-art QD-LSCs, namely, the presence of airborne pollutants (dust), water droplets, and dried deposits. Our results show that dust is unexpectedly insignificant for the waveguiding of the concentrated luminescence and only reduces the LSC efficiency through a shadowing effect when deposited on the outer surface, while dust accumulation on the inner LSC side increases the output power due to backscattering of transmitted sunlight. Water droplets, on the other hand, do not dim the incident sunlight, but are detrimental to waveguiding by forming an optical interface with the LSC. Finally, dried deposits, which mimic the evaporation residues of heavy rain or humidity, have the worst effect of all, combining shading and waveguide losses. These results are relevant for the design of application-specific surface functionalization/protection strategies real LSC modules.

Luminescent Solar Concentrators with Dual Functions of Photovoltaic and Piezoelectric Properties for Wireless Self‐Powered Speed Measurement

AbstractThe solar‐only response nature limits the luminescent solar concentrators (LSCs) to solar harvesting rather than responding to other stimuli, which restricts the role of LSCs to energy supply in self‐powered internet of things (IoT) systems, and the application potential of LSCs in self‐powered devices has been seriously overlooked. In this work, LSCs with photovoltaic and piezoelectric features are proposed for the first time, extending the application scenario of LSCs to self‐powered sensors with pressure responsiveness. The luminescent layer of perovskite‐polymer composite film is prepared via in situ blade coating with the piezoelectric polymer matrix of poly(vinylidenefluoride‐trifluoroethylene) (P(VDF‐TrFE)). P(VDF‐TrFE) possesses stronger DMF adsorption capacity and higher electroactive phase content than a conventional piezoelectric matrix of poly(vinylidene fluoride) (PVDF), which not only reduces the residual‐solvent‐induced defects in perovskite luminophores, but also brings a sensitive pressure response to LSCs. The dual‐functional LSCs achieve a power conversion efficiency of 1.01% and a output piezoelectric voltage of 0.95 V can be obtained even at a low pressure of 0.16 kPa. A self‐powered speed measurement system is demonstrated, and the actual speed measurement is carried out. Such dual‐functional LSCs show great potential in self‐powered electrical devices, which can be applied to low‐energy‐consumption IoT systems and other commercial smart home products.