Light Energy Research Articles

Boosted photoinduced charge separation in FeNi2S4@Cd0.9Zn0.1S Step-scheme heterojunction for photothermal assisted photocatalytic water splitting into hydrogen

Rational design of photocatalysts with photothermal effect to maximize light utilization is pivotal in achieving superior photocatalytic efficiency. In this work, by coating Cd0.9Zn0.1S (CZS) nanorods on hollow FeNi2S4 (FNS) microspheres with photothermal effect, a novel FeNi2S4@Cd0.9Zn0.1S (FNS@CZS) Step-scheme (S-scheme) heterojunction photocatalyst was constructed for efficient photothermal-assisted hydrogen (H2) evolution via simultaneously employing light and thermal energy. The hollow structure of FNS microsphere not only provides abundant reactive sites but also serves as a supportive substrate for CZS nanorods, effectively inhibiting their agglomeration. And the unique hollow structure of FNS allows for multiple reflections and refractions of visible light, enhancing the local temperature of the photocatalyst. This effectively minimizes thermal losses within the composite system, thereby enhancing the efficiency of light energy utilization. Furthermore, the formation of the S-scheme heterojunction facilitates the efficient separation of photogenerated charge carriers and enhances the activity of redox reactions, thereby boosting the overall photocatalytic activity. Experimental results reveal that the H2 production rate of the FNS@CZS heterojunction reaches 12.9 mmol·g−1·h−1, which is 25.1 times higher than that of pristine CZS. By controlling the experimental temperature, the impact of the photothermal effect on the photocatalytic H2 production rate has been clarified. According to relevant evidence from infrared thermography and DFT calculations, comprehensive analyses and discussions were conducted on the photothermal effect and S-scheme charge transfer mechanisms. This study offers guidance on designing photothermal-enhanced photocatalysts to achieve satisfactory H2 production activity.

Nickel-Induced Dual Carbon Networks Encapsulating Phase Change Materials for Photothermal Conversion and Storage.

Bifunctional phase change materials (PCMs) with efficient energy storage and photothermal conversion capabilities have tremendous potential to be applied in advanced thermal management. However, classical organic PCMs with high latent heat are challenged by poor light harvesting, low thermal conductivity, and leakage risks. Here, we design a unique dual-carbon network with Ni nanoparticles (NPs), confined carbon nanotubes (CNTs) shuttling in carbon honeycombs (CH), namely, CH@Ni-CNTs, to encapsulate paraffin wax (PW) that can facilitate the light capture and photothermal conversion dynamics. Benefiting from the physical adsorption of the hierarchical porous structure, the obtained PW/CH@Ni-CNTs composite PCMs show a high phase change enthalpy of 131.0 J g-1 and long-lasting thermal stability of up to 300 heating-cooling cycles. Moreover, an outstanding photothermal energy conversion efficiency of 96.9% is achieved due to the synergistic effect of the dual carbon network and confined Ni NPs. The CNTs shuttled CH network affords multiple reflection chambers and a thermal conductive pathway, while the localized surface plasmon resonance (LSPR) effects of Ni NPs concentrate the incident light energy to generate and accelerate the transport of active "hot electron", thus collectively contributing to the excellent photothermal properties of the composite PCMs. This study presents a bifunctional Ni-induced dual-carbon network system for the controllable preparation of composite PCMs, and it sheds light on the photothermal conversion mechanisms.

Light intensity moderates photosynthesis by optimizing photosystem mechanisms under high VPD stress

In recent decades, the global increase in vapor pressure deficit (VPD) has significantly inhibited plant growth and photosynthesis. Light intensity, a crucial environmental regulator, plays a vital role in stress response and photosynthetic adjustment. This study investigated whether increasing light intensity under high VPD conditions could optimise the photosystem and thereby enhance photosynthesis. We designed experiments using factorial combinations of two VPD levels (HVPD; high VPD, AVPD; appropriate VPD) and two irradiance gradients (L300; 300 μmol photons m−2 s−1, L600; 600 μmol photons m−2 s−1). Under high VPD, plants protect their photosystems by reducing light energy absorption and limiting photosynthetic electron flow, which results in reduced photosynthesis. However, when exposed to HVPD + L600, plants exhibited increased light energy absorption, as evidenced by elevated chlorophyll b and carotenoid levels, enhanced response to irradiance, and decreased NPQ and Y(NO). This regimen also enhanced photosynthetic electron transport by increasing the total driving force and plastoquinone pool, consequently improving the photochemical efficiency of the photosystem and ultimately boosting the net photosynthetic rate by 46.9%. This study confirmed that modulating light intensity under high VPD stress can improve photosynthesis by optimizing the photosystem. This novel approach can be utilized to enhance tomato production in arid regions.

Accelerating Charge: Add-Ons to Rest Mass and Field Energy

We present—in the framework of classical theory—a self-consistent derivation scheme which produces equations for the calculation of add-ons to the full field energy and to the effective mass of a charge moving with acceleration, which may be practically used for analyses in various scenarios. The charge is treated as a quasi-point-like charge; this helps to resolve the complications of the “infinite” electromagnetic energy, which are avoided by the procedure of slightly “spreading” the charge. As a result, the concept of the size of the particle takes a straightforward physical interpretation. Indeed, it is within the charge spread, at scales smaller than Compton’s length, where the quantum-field-mechanics approach to be applied. Beyond this region, no “infinite” tails of quantities accumulate. The seeming divergences of the integrals at the upper limits are not physical if one takes into account that the charge moves with acceleration only for a finite duration of time; every real physical process has its beginning and its end. The key focus of this paper is on the methodological aspects of the calculations.

Carbon monochalcogenides/graphene van der Waals heterostructures for sustainable energy harvesting

We constructed the van der Waals (vdW) heterostructures by stacking graphene (G) on top of carbon-based monochalcogenides (CX; X = S, Se, and Te) monolayer in two different patterns (I and II) and predicted various physical properties through first-principles calculations. Among the six heterostructures, three systems (CS/G in Pattern-I and II, and CSe/G in Pattern-II) were found to be most stable. Additionally, the calculated electronic properties confirmed that the CS/G and CSe/G heterostructures in Pattern II are indirect semiconductors with narrow band gap values of 0.49 and 0.30 eV, respectively. Notably, both heterostructures (CS/G and CSe/G) exhibit significantly larger electron carrier mobilities of 762.83 and 206.84 m2/Vs at room temperature, respectively. Furthermore, intrinsic and interface dipoles in both heterostructures were found to align along the +z axis, enhancing charge transfer at the interface and narrowing the band gap, particularly in CSe/G. This polarization effect contributes to the observed high electron mobility and thermoelectric performance. Electronic transport coefficients like the Seebeck coefficient, electrical conductivity, and thermoelectric power factor are predicted using the Boltzmann transport theory implemented in the BoltzTrap code. The highest power factor 249mW/mK2 was achieved for the CSe/G heterostructure at 300K, demonstrating its ability for good thermoelectric purposes. Besides, the computed optical properties revealed the potential of the CS/G heterostructure as a light absorber with an excellent solar light energy conversion efficiency (η) of 23.57 % for solar cell device applications. Our predictions show that the novel 2D CX/G vdW heterostructures could be promising candidates for designing new solar and heat energy harvesting devices.

MXene Hybridized Polymer with Enhanced Electromagnetic Energy Harvest for Sensitized Microwave Actuation and Self-Powered Motion Sensing

HighlightsAn alternative electromagnetic attenuation pathway is proposed in the MXene-polymer hybrid structure, distinct from conduction loss, for generalizing the results to a wider range of electromagnetic-thermal driven soft materials and devices.By efficiently harvesting and converting electromagnetic energy, the response time of the hybrid polymer to microwave exhibits 87% reduction with merely 0.15 wt% MXene.A new mode of self-powered motion sensing based on deformation-driven piezoelectric effect is developed, enhancing the material’s intelligence.

A “super-off” photoelectrochemical biosensor based on Cu-BTC nanozyme quenching strategy for the detection of dibutyl phthalate plasticizer

Ultrasensitive detection of phthalic acid (PAEs) is an extremely critical mission in environmental monitoring. We designed a “super-off” photoelectrochemical (PEC) biosensor by using MoO3/Bi2MoO6 as photoanode and copper(II) benzene-1,3,5-tricarboxylate (Cu-BTC) nanozyme as highly efficient signal quencher. It was found that the PEC signal of MoO3/Bi2MoO6 photoelectric material is very sensitive to the concentration of co-reactor H2O2. Therefore, a target-triggered endonuclease-assisted recycle was employed to convert the target DBP into amount of output DNA, which can trigger the assembly of DNA nanonet for the immobilization of Cu-BTC nanozyme. Thanks to the peroxidase-like activity of Cu-BTC, a “super off” photocurrent was observed due to the consumption of electron donor H2O2 in the electrolyte. Compared with the traditional quenching strategies such as steric hindrance and light energy competition, this enzymatic reaction on the electrode interfaces is more effective to induce the distinct decrease of photocurrent for analysis. Ultimately, the constructed PEC sensor exhibited a broad linear range from 1 fM to 100 nM and a detection threshold of 0.3 fM. This work highlights the significance of using peroxide-mimic enzyme as a signal amplifier in PEC sensing platform for environmental monitoring.

Regulation of electron density in Pt nanoparticles via bimetallic metal-organic frameworks for enhancing photothermal catalysis of toluene decomposition

Volatile Organic Compounds (VOCs) are omnipresent in the sphere of human industrial, harboring latent adverse consequences for health and the ecological system. The photothermal catalytic oxidation of VOCs is an advanced integrated technology that harnesses the combined effects of light and heat energy to enhance the efficiency of VOCs degradation. Herein, a bimetallic Metal-Organic Framework (MOF) was synthesized with the incorporation of Ce into the UiO-66-NH2(Zr) (i.e., UNH(Zr)), UiO-66-NH2(Zr2Ce) (i.e., UNH(Z2C)), which was achieved with Ce atom substituting for a portion of Zr atom within the Zr-oxo clusters. Pt nanoparticles (NPs) are integrated with MOFs to form composites using the dual-solvent method. Ce-oxo fulfills a bifunctional role: it not only facilitates the enhancement of the ligand-to-metal charge transfer (LMCT), but also establishes interaction with Pt NPs. Ce-oxo mediates an enhancement of electron density on Pt NPs. This phenomenon enhances the adsorption and activation of oxygen, significantly boosting the photocatalytic performance for toluene degradation, as demonstrated by a reduction of 30 ℃ for complete mineralization of toluene as compared to that of Pt@UiO-66-NH2(Zr) (i.e., PUNH(Zr)). This study potentially offers new insights into the relationship between electron transfer effects in bimetallic MOF-based catalysts and their efficient catalytic performance for VOCs degradation.

Improving Solar Cell Efficiency of Silicon and Silicon Tandem Structure by Using Surface Modification

Silicon heterojunction (SHJ) solar cells face challenges in maximizing energy capture due to limitations in light collection and surface passivation. To address this, the use of SHJ tandem solar cells in a back‐to‐back configuration is explored, allowing illumination from both sides to enhance light absorption and energy generation. This study aims to improve the stability and efficiency of these cells through Al2O3 and Nafion surface treatments. Al2O3 is deposited to enhance bifacial light collection, while Nafion is applied for surface passivation to increase the fill factor (FF). The method involves adding 0.1–0.6 units of incident light to the rear of the cells to evaluate the effects of these treatments. The results show a 2.06% increase in efficiency with Al2O3 and a 1.72% improvement with Nafion under standard illumination conditions. The optimized tandem SHJ with Al2O3 and Nafion achieves a Jsc of 62.01 mA cm−2, Voc of 650.63 mV, FF of 76.49%, and an efficiency of 30.86%. These findings demonstrate the significant potential of these surface treatments to enhance the overall performance of bifacial back‐to‐back tandem SHJ solar cells.

A typha orientalis-inspired 3D Janus solar evaporator with controllable wettability for highly efficient and stable solar desalination

Solar-powered interfacial evaporators, though promising for seawater desalination and wastewater treatment, but suffer from the problems of monolithic structure and complex preparation. It is of great importance to develop a multi-layered solar evaporator that possesses stable and high-efficiency photothermal performance. Our research employs simple liquid-phase polymerization and chemical deposition methods to achieve this. The objective of this study is to develop a highly efficient solar evaporator, designated as SA/MWCNTs@PPy/MWCNTs-NH2@PU (SMPMPU), by integrating stearic acid (SA), multi-walled carbon nanotubes (MWCNTs), polypyrrole (PPy), and aminated multi-walled carbon nanotubes (MWCNTs-NH2) within a polyurethane (PU) matrix. Inspired by typha orientalis, this evaporator boasts a highly antibacterial, self-floating Janus bilayer structure. This double-layered Janus solar evaporator utilizes the capillary adsorption effect to regulate the flow of water. It slows down heat transfer and significantly improves energy utilization efficiency. The resulting SMPMPU solar evaporator demonstrates a solar steam conversion efficiency with an evaporation rate of 2.40 kg·m−2·h−1, which is attributed to the material's efficient absorption of light energy. Its evaporation efficiency under one sun illumination reaches 92.76 %, which can be credited to the Janus interface facilitating the absorption and evaporation of water molecules. The Janus bilayer structured solar evaporator developed in this study holds great promise and is anticipated to find widespread applications in seawater desalination and other related fields.

Charged Dyson shells supported in curved spacetimes of spherically symmetric central compact objects

It is proved that charged thin shells (charged Dyson shells) can be supported in unstable static equilibrium states around spherically symmetric central compact objects. The regime of existence of the composed central-compact-object-static-charged-shell configurations is characterized by the inequalities m(m+2M)<|q|<M+M2+m2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{m(m+2M)}<|q|<M+\\sqrt{M^2+m^2}$$\\end{document}, where {m,q}\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\{m,q\\}$$\\end{document} are respectively the proper mass and the electric charge of the supported shell and M is the mass of the central compact object (a black hole or an horizonless compact star). We reveal the physically interesting fact that the supported charged shells become marginally-stable in the |q|/m(m+2M)→1+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|q|/\\sqrt{m(m+2M)}\\rightarrow 1^+$$\\end{document} limit, in which case the lifetime (instability timescale) of the composed system can be made arbitrarily large. Our analysis goes beyond the test shell approximation by properly taking into account the exact gravitational and electromagnetic self-interaction energies of the spherically symmetric shell in the curved spacetime. In particular, the existence of the composed compact-object-charged-shell static configurations in the Einstein–Maxwell theory is attributed to the non-linear electromagnetic self-energy of the supported shell.

Harnessing the power of targeted metal nanocarriers mediated photodynamic and photothermal therapy.

The treatment of cancer has become a profoundly intricate procedure. Traditional treatment methods, including chemotherapy, surgery and radiotherapy, have been utilized, while notable progress has been achieved in recent years. Among targeted therapies for cancer, folic acid (FA) conjugated metal-based nanoparticles (NP) have emerged as an innovative strategy, namely for photodynamic therapy (PDT) and photothermal therapy (PTT). These NP exploit the strong attraction between FA and folate receptors, which are excessively produced in several cancer cells, in order to enable precise administration and improved effectiveness of treatment. During PDT, metal-based NP functionalized with FA are used as photosensitizers which are activated by light, and produce reactive oxygen species that cause cancer cells to undergo apoptosis. Within the framework of PTT, these NP effectively transform light energy into concentrated heat, specifically targeting and destroying tumor cells. This review examines the fundamental mechanisms by which these NP improve the effectiveness of PDT and PTT while simultaneously presenting important findings that demonstrate the effectiveness of FA-functionalized MNP in laboratory and animal models. In addition, the paper also discusses the problems and potential directions for their clinical translation.

Compact highly sensitive photothermal RT-LAMP chip for simultaneous multidisease detection.

Developing instant detection systems with disease diagnostic capabilities holds immense importance for remote or resource-limited areas. However, the task of creating these systems-which are simultaneously easy to operate, rapid in detection, and cost-effective-remains a challenge. In this study, we present a compact highly sensitive photothermal reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) chip (SPRC) designed for the detection of multiple diseases. The nucleic acid (NA) amplification on the chip is achieved through LAMP driven by either LED illumination or simple sunlight focusing. SPRC performs sample addition and amplification within a limited volume and autonomous enrichment of NA during the sample addition process, achieving a limit of detection (LOD) as low as 0.2 copies per microliter. Through 120 clinical samples, we achieved an accuracy of 95%, with a specificity exceeding 97.5%. Overall, SPRC has achieved promising progress in the application of point-of-care testing (POCT) by using light energy to simultaneously detect multiple diseases.

Hetero‐Dimensional Micro‐Nano Architectures Toward Electromagnetic Devices and Hybrid Energy Transport

AbstractHuman spaceflight, lunar exploration projects, and interstellar travel are the grand visions of human exploration of the universe. However, the energy sustainability of these projects is a concern. Electromagnetic functional materials and devices are expected to fulfill their potential in electronic communication and energy utilization. Herein, hetero‐dimensional micro‐nano architectures composed of Cu3Se2 microspheres and reduced graphene oxide (rGO) sheets are fabricated for the first time by the sacrificial template method, anion substitution engineering, electrostatic adsorption, and reduction‐oxidation reaction. Based on the excellent electromagnetic response of the composites, they exhibit strong and ultra‐wide microwave absorption ability with the effective absorption bandwidth (EAB) reaching 8.24 GHz at a thickness of 2.2 mm. In addition, an electromagnetic metamaterial with an EAB to ≈13.5 GHz is proposed, exhibiting significant properties. More significantly, the composites can be used to construct a range of electromagnetic devices: a spiral antenna with adjustable return loss and gain, with a maximum gain of up to 2.5 dBi; a microstrip power divider that can efficiently split the input signal into four equal parts and output it; a hybridized energy transport device can convert and store electromagnetic energy. This work provides new inspiration for electromagnetic protection, electronic communication, and energy development.

Green synthesis of infrared controlled AgNP/graphite/polyvinylidene fluoride composite membranes for removal of organic pollutants

The effectiveness of light-sensitive particle-added composites as alternative materials in the treatment of waste water was investigated. Infrared responsive polyvinylidene membranes were prepared with anchoring the graphite supported silver particles reduced by quince seed extract. X-ray diffractometer, scanning electron microscope and Fourier transform infrared spectroscopy analysis were used to characterize physicochemical and structural properties of composites. Photoluminescence, surface area and contact angle measurements were carried out. The filtration performances of the membranes were tested under infrared light in a continuous flow system. Methyl orange and bovine serum albumin solutions were used as model pollutants. The silver-graphite additive acted as light absorber and energy converter. Owing to the photothermal effect, the water flux, rejection and roughness of the AgNP-G-P membrane improved significantly, and those were recorded as 74.7 L.m−2.h−1.bar−1, 54.6 % and, 75.0, respectively (32.5, 22 and 74.1 %, respectively, for PVDF). The composites almost retained their initial performance after repeated use and did not cause solution leaching. In this study photothermal particles, which are frequently used in medical applications, were successfully adapted to the filtration system. It has the ability to add a specific and new dimension to the protection of the environment by purifying wastewater.

A hybrid piezoelectric–electromagnetic body energy harvester: design and experiment validation

Abstract The rapid advancement of electronic devices and wireless sensors has heightened the demand for energy sustainability and portable power solutions. Traditional human energy harvesters have limitations in harvesting energy from ultra-low-frequency human motion due to issues related to unstable energy output and wearing comfort. To address this challenge, a piezoelectric–electromagnetic hybrid energy harvesting (HP-EEH) structure designed for the hip joint area. This innovative design employs magnetically coupled frequency boosting alongside electromagnetic energy capture to achieve high output power. Firstly, the structure and principle of the energy capture device are introduced, and the electromechanical coupling model of the energy harvester is derived using Hamilton’s principle. Furthermore, the system is numerically simulated, and the voltage output characteristics of the piezoelectric unit and the electromagnetic unit are analyzed by using the finite element analysis software. Finally, the experimental setup of the (HP-EEH) is constructed, and the voltage output characteristics are tested for different swinging angles and positions. The results show that two parts of energy can be captured simultaneously under ultra-low-frequency motion conditions. At a swing angle of 50 degrees, the piezoelectric and electromagnetic units achieved maximum output power values of 14.96 µW at 0.8 Hz and 10.4 µW at 1.2 Hz, respectively. Incorporating the output power of the electromagnetic unit aims to address the power consumption requirements of low-power devices better.

Photosynthesis Responses to the Infection with Plant Pathogens.

Photosynthesis, the remarkable process by which green plants synthesize nutrients using light energy, plays a crucial role in sustaining life on Earth. However, the effects of pathogens on photosynthesis are not widely understood. In general, a reduction of photosynthesis occurs upon the infection with pathogens. Two main scenarios are responsible for the reduction in photosynthetic capacity. In the first scenario, the pathogen attacks green aerial tissues such as caused by fungal and bacterial leaf spots and blights which affect photosynthesis by destroying green leaf tissue or causing defoliation. This leads to a decrease in the photosynthetic area, ultimately reducing photosynthesis. Interestingly, even when the overall chlorophyll content of leaves is significantly reduced due to pathogen invasion, the remaining chlorophyll-containing leaf area may maintain or even enhance its photosynthetic efficiency. This compensatory mechanism helps mitigate the loss of photosynthetic area. However, the overall yield of the plant is still affected. The second scenario is a reduction in chlorophyll content due to chlorosis, which is characterized by yellowing of leaves. It is a common symptom of plant diseases. It refers to a reduction in the amount of chlorophyll per chloroplast, rather than a decrease in chloroplast number. Diseases caused by viruses and phytoplasmas often exhibit chlorosis. While pathogens disrupt photosynthesis, plants exhibit significant adaptations to cope with these challenges. Understanding these interactions is essential for sustainable agriculture and ecosystem health. Thus, in this review, we discuss the effect of several pathogens on the photosynthesis processes and efficiency in detail.

Simultaneous enhancement of visible light absorption and energy storage performances of W5+ implanted WO3-x thin film electrodes

Herein, we report the implantation of oxygen vacancy dopants in electro-coated WO3 thin film electrodes for enhanced energy and environmental applications. The implantation method involved partial de-oxidation in sodium borohydride to introduce oxygen vacancies into the WO3 electrodes. The doped WO3-x demonstrated a significantly lowered average band energy of 2.11 eV, indicating its ability to absorb over 75 % of the visible light spectrum. Moreover, a thin film asymmetric supercapacitor assembled with WO3-x negatrode demonstrated an improved areal capacitance of 1.15 mFcm−2 and energy density of 0.33 μWhcm−2 while consuming power at 17.50 μWcm−2 when cycled at 25 μAcm−2. Our solution-processed technique allows for controllable vacancy implantation and binder-free coating of WO3-x on various substrates. It significantly reduces the processing time and requires low energy consumption, making it a practical and efficient method for enhancing the overall photo-conversion and energy storage performances of WO3-based electrodes.

Light-Triggered Droplet Gating Strategy Based on Janus Membrane Fabricated by Femtosecond Laser.

The characteristics of the directed transport of liquids based on Janus membranes play a crucial role in practical applications in energy, materials, physics, chemistry, medicine, biology, and other fields. Although extensive progress has been made, it is still difficult to realize the accurate controllability of liquid directional transmembrane transport. The current gating strategies for the directed transport of liquids based on Janus membranes still have some limitations: (a) using magnetic fluid may cause contamination due to the addition of new substances and (b) utilizing hydrophobicity/hydrophilicity conversion of titanium dioxide requires a long switching time (over 30 min). Herein, a strategy is proposed to precisely control liquid directional transport by altering the wettability of droplets on Janus films prepared by a femtosecond laser through photothermal effects. Infrared laser irradiation on Janus film coated with CNTs can effectively convert light energy into thermal energy, rapidly increase the surface temperature of Janus film, and change the wettability of the liquid on the film. Liquid transmembrane directional transport can be achieved within a few seconds without contaminating the transported liquid. The proposed gating strategy can enable the application of Janus membranes in various scenarios such as microchemical reactions, biological cell culture, and interface self-propulsion.

Efficiency Limits of Energy Conversion by Light-Driven Redox Chains.

The conversion of absorbed sunlight to spatially separated electron-hole pairs is a crucial outcome of natural photosynthesis. Many organisms achieve near-unit quantum yields of charge separation (one electron-hole pair per incident photon) by dissipating as heat more than half of the light energy that is deposited in the primary donor. Might alternative choices have been made by Nature that would sacrifice quantum yield in favor of producing higher energy electron/hole pairs? Here, we use a multisite electron hopping model to address the kinetic and thermodynamic compromises that can be made in electron transfer chains, with the aim of understanding Nature's choices and opportunities in bioinspired energy-converting systems. We find that if the electron-transfer coordinates are even weakly coupled to a high-frequency vibrational mode, substantial energy dissipation is necessary to achieve the maximum possible energy storage in an electron-transfer chain. Since high-frequency vibronic coupling is common in physiological redox cofactors, we posit that biological reaction centers have recruited a strategy to convert light energy into redox potential with the near-optimum energy efficiency that is possible in an electron-transfer chain. Our simulations also find that charge separation in electron-transfer chains is subject to a minimum intercofactor separation distance, beneath which energy-dissipating charge recombination is unavoidable. We find that high quantum yield and low energy dissipation can thus be realized simultaneously for multistep electron transfer if recombination pathways are uncoupled from high-frequency vibrations and if the cofactors are held at small-to-intermediate distances apart (ca. 3 to 8 Å edge-to-edge). Our analysis informs the design of bioinspired light-harvesting structures that may exceed 60% energy efficiency, as opposed to the ∼30% efficiency achieved in natural photosynthesis.