Limited Conversion Efficiency Research Articles

Insight into the synergistic effects of surface microstructures and wall peristalsis on glucose production in a bionic microreactor

The enzymatic hydrolysis stage is regarded as a key step in the production of biofuels derived from lignocellulosic biomass, but the elevated production expenses and limited conversion efficiency are still not favorable for practical applications. In this study, inspired by the efficient degradation of cellulose in the termite gut, a cellulase-loaded flexible microreactor model with bionic surface structures was first proposed for the production of fermentable glucose. In such a system, the fold-like structures can provide more enzyme loading sites, and villus-like structures can not only increase enzyme loading but also improve radial transfer in the microreactor. These two structures synergized well and resulted in a 58.5% increase in glucose production compared to the control. Applying peristalsis can further enhance mass transfer by the formation of backflow and vortex, and reducing the peristaltic period is more effective than increasing the peristaltic amplitude for glucose production enhancement. The glucose concentration obtained by the synergistic enhancement of peristalsis and surface structure was 2.3 times of the control. Moreover, for reactions with higher intrinsic reaction rates, the system is in a mass transfer-limited state and peristaltic enhancement is more effective. These results give insight into the design of the bionic flexible microreactor for efficient glucose production.

Effect of Ni Doping on the Thermoelectric Properties of YbCo2Zn20.

Thermoelectric devices are both solid-state heat pumps and energy generators. Having a reversible process without moving parts is of high importance for applications in remote locations or under extreme conditions. Yet, most thermoelectric devices have a rather limited energy conversion efficiency due to the natural competition between high electrical conductivity and low thermal conductivity, both being essential conditions for achieving a high energy conversion efficiency. Heavy-fermion compounds YbT2Zn20 (T = Co, Rh, Ir) have been reported to be potential candidate materials for thermoelectric applications at low temperatures. Motivated by this result, we applied chemical substitution studies on the transition metal site in order to optimize the charge carrier concentration as well as promote more efficient phonon scatterings. Here, we present the latest investigation on the Ni-doped specimens YbCo2-xNixZn20, where enhanced thermoelectric figure of merit values have been obtained.

Simulation of Extreme Ultraviolet Radiation and Conversion Efficiency of Lithium Plasma in a Wide Range of Plasma Situations

Based on the detailed term accounting approach, the relationship between extreme ultraviolet conversion efficiency and plasma conditions, which range from 5 to 200 eV for plasma temperature and from 4.63 × 1017 to 4.63 × 1022 cm−3 for plasma density, is studied for lithium plasmas through spectral simulations involving very extended atomic configurations, including a benchmark set of autoionizing states. The theoretical limit of the EUV conversion efficiency and its dependence on sustained plasma time are given for different plasma densities. The present study provides the necessary understanding of EUV formation from the perspective of atomic physics and also provides useful knowledge for improving EUV conversion efficiency with different technologies.

Ultrahigh power factor and excellent solar efficiency in two-dimensional hexagonal group-IV–V nanomaterials

The mesmerizing physical properties of two-dimensional (2D) nanomaterials have resulted in their enormous potential for high-power solar energy conversion and long-term stability devices. The present work systematically investigated the fundamental properties of monolayered 2D group-IV–V materials using a combined approach of first-principles calculations and Boltzmann transport theory, specifically the thermoelectric and optical properties, for the first time. The structural and lattice dynamics analysis disclosed the energetic, dynamical, and mechanical stabilities of 17 out of 25 considered materials. The electronic properties’ calculation shows that all the stable materials exhibit a semiconducting nature. Additionally, the energy–momentum relation in a few systems reveals the quartic Mexican-hat-like dispersion in their valence band edges. Owing to the larger depth of Mexican-hat dispersion and the larger height of density step function modes, the hole carrier mobilities of SnN (761.43 m2/Vs), GeN (422.80 m2/Vs), and SiN (108.90 m2/Vs) materials were found to be significantly higher than their electron mobilities at room temperature. The achieved high Seebeck coefficient and electrical conductivity at room temperature result in excellent thermoelectric power factors for GeN (3190 mW/mK2), SiN (1473 mW/mK2), and CAs (774 mW/mK2) materials, manifesting their potential for thermoelectric devices. Further, the calculated optical and solar parameters demonstrate an exceptionally high value (27.25%) of theoretical limits of power conversion efficiency for the SnBi material, making it a suitable candidate as a light-absorbing material in solar cell devices. The present theoretical work filters out the potential 2D group-IV–V materials for solar and heat energy-harvesting devices.

Optimal Selection for Redox Couples and Enhanced Performance through Magnetic Nanofluid Electrolyte in Solar Flow Batteries

The limited photoelectric conversion efficiency poses one of the critical constraints on commercializing solar flow batteries (SFBs). This study compares the chemical and photoelectrochemical properties of three commonly used redox couples. Additionally, magnetic Fe3O4 nanoparticles, for the first time, are introduced to optimize the electrolyte, and they are compared with the original electrolyte. Across different redox couples, the variations in semiconductor flat-band potentials and carrier concentrations result in changes in photoelectric current density. Notably, FeCl2/FeCl3 redox coupled with TiO2 photoelectrodes exhibits the highest photoelectric current density, reaching 75.7 µA cm−2. However, the trade-off of this electrolyte, i.e., providing high photocurrent while being unable to supply sufficient open-circuit voltage, imposes limitations on the practical application of SFBs. Alternatively, for TEMPO and 4-OH-TEMPO electrolytes, which can provide a higher open-circuit voltage, the electrochemical activity is enhanced, and the solution ohmic resistance is reduced by introducing magnetic nanoparticles to form a magnetic nanofluid. As a result, the photoanode’s photocurrent density increases by 36.6% and 17.0%, respectively, in the two electrolytes. The work reported here effectively addresses the current issue of low photocurrent density in SFBs and presents new optimization strategies for SFBs.

Energy Generation Intensity (EGI) of Solar Updraft Tower (SUT) Power Plants Relative to CSP Plants and PV Power Plants Using the New Energy Simulator “Aladdin”

The current investigation provides information about solar updraft tower power plants, SUTPPs (also called solar chimney power plants, SCPPs), which form a unique method of solar-powered electricity production through a ducted wind turbine driven by induced airflow as a result of solar heating. The investigation is conducted using numerical modeling via the system-level simulation tool Aladdin (developed and released freely by the Institute for Future Intelligence, IFI) for solar energy systems, wind energy systems, or the built environment. The Aladdin energy simulator is first evaluated here by comparison with published experimental and numerical results corresponding to the historical 50 kW prototype SUTPP that was successfully tested in Manzanares (Spain) between 1982 and 1989. This prototype has a height of about 195 m for the chimney (the updraft tower) and a radius of about 122 m for the solar heat absorber (the solar air collector or the greenhouse). Next, various climate and performance characteristics are investigated and contrasted for nine different locations around the world with a similar latitude of 24°, which is within the sunbelt, assuming that the same Manzanares SUTPP prototype geometry is employed in these locations. These nine locations are Muscat (Oman), Al Jawf (Libya), Riyadh (Saudi Arabia), Karachi (Pakistan), Ahmedabad (India), Havana (Cuba), Culiacán (Mexico), Dhaka (Bangladesh), and Baise (China). The energy generation intensity (EGI) for the Manzanares-type solar updraft tower power plant in these nine examined locations was between 0.93 kWh/m2 per year (in Baise) and 2.28 kWh/m2 per year (in Muscat). Also, Muscat had the smallest seasonality index (maximum-to-minimum monthly electric output) of 1.90, while Baise had the largest seasonality index of 4.48. It was found that the main limitation of the overall SUTPP energy conversion efficiency is the chimney efficiency (the process of accelerating the air after entering the chimney). This study concludes that solar updraft towers (SUTs) cannot compete with existing mature and modular renewable energy alternatives, particularly photovoltaic (PV) panels, if the aimed use is commercial utility-scale electricity generation. Instead, SUTs may become attractive and achievable if viewed as hybrid-use projects by serving primarily as a large-scale greenhouse area for agricultural applications while secondarily allowing energy harvesting by generating clean (emissions-free) electricity from the incoming solar radiation heat.

Second Harmonic Generation Control in 2D Layered Materials: Status and Outlook

AbstractSecond harmonic generation (SHG) as an essential nonlinear optical effect, has gradually shifted its research trend toward the integration and miniaturization of photonic and optoelectronic on‐chip devices in recent years. 2D layered materials (2DLMs) open up a new research paradigm of nonlinear optics due to their large second‐order susceptibility, atomically thin structure, and perfect phase‐matching. However, 2DLMs are facing a bottleneck of weak SHG conversion efficiency limit caused by short light–matter interaction lengths at a nanoscale. Moreover, advances in integrated on‐chip SHG devices based on 2DLMs rely on the continuing development of novel strategies with tunable and efficient SHG responses. Here, this review provides a comprehensive overview of recent progress in exploring highly efficient and tunable SHG responses in 2DLMs. Various modulation and enhancement strategies for the SHG response of 2DLMs are extensively studied and systematically discussed, which can be classified into two categories: symmetry breaking and light‐matter interaction enhancement. Moreover, remaining challenges and outlooks toward further extending and realizing the practical applications of 2DLMs in nonlinear on‐chip integrated devices with SHG modulation and enhancement characteristics are discussed.

Recent progress in monolithic two-terminal perovskite-based triple-junction solar cells

Monolithic perovskite-based triple junction solar cells have the potential to surpass the power conversion efficiency (PCE) limits of single and dual-junction solar cells.

Modelling recycling for the life cycle assessment of perovskite/silicon tandem modules

With the massive growth of the global capacity of photovoltaics (PV) over the last decade, the PV waste is expected to increase dramatically in the near future. Having potential to reduce the use of raw materials and preserve natural resources, PV recycling is attracting more and more attention. This being said, the environmental impacts over the life cycle of PV technologies, including the end-of-life (EoL) stage, should be evaluated carefully. Life cycle assessment (LCA) is currently the most common methodology to assess the potential environmental impacts of a product throughout its entire life cycle. However, the modelling of recycling in LCA has always been a challenge and no consensus has yet been reached, since the treatment of recycling does not only involve an EoL management of waste, but also the production of recycled material. Perovskite on silicon tandem is a widely investigated emerging PV technology having the potential to overcome the power conversion efficiency (PCE) limit of the single-junction crystalline silicon technology. The EoL modelling seems more challenging in the case of emerging technologies for which the EoL is more uncertain than for established technologies. In this article, six common and important approaches of EoL modelling in LCA were applied to future perovskite/silicon tandem modules to analyze the effect of the different EoL modelling approaches on the LCA results. The aim was to identify the most suitable methodological approaches to account for recycling, when modelling the life cycle of PV modules. The environmental performance of perovskite/silicon tandem modules was assessed over their life cycle and expressed in terms of impacts per m2 of module. After testing the six EoL modelling approaches and comparing the LCA results, the EoL modelling choice was found to lead to non-negligible differences. For example, in terms of climate change, the impact of the tandem modules ranges from 45 to 59 kg CO2-eq/m2. Among the six EoL modelling options, the approaches of simple cut-off and cut-off with economic allocation are more oriented towards the promotion of high rates of recycled material integrated as an input to the assessed product among industrial actors, while the approach of closed-loop allocation provides incentives to maximize the ratio of recycling at the EoL, regardless the initial ratio of recycled content within the product. Some approaches such as the circular footprint formula (CFF) tend to provide both incentives to increase the content of recycled input material in the manufacturing of the product and the recycling ratio at the EoL of such product. After applying the different alternatives, a set of recommendations to select the relevant EoL modelling approaches are provided: 1) the CFF is recommended as a representative approach due to its wide applicability, tending to provide an intermediate result and reflecting the characteristics of materials; 2) sensitivity analysis should be applied to check the robustness of the results, 3) the cut-off approach and the closed-loop allocation should be used at least for the sensitivity analysis.

First-principles investigation of photovoltaic material based on lanthanide metals

Searching for photovoltaic materials with high efficiency conforms to the goal for accessing low carbon and sustainable energy. This work explores the properties of RA3X3 compounds (R = La, Sm, Gd, Tb, Dy, Ho, Er; A = Cd, Zn; X = As, P) through a screening process, focusing on the huge potential of RCd3P3 series for further investigation in photovoltaic applications. Results show that RCd3P3 series with a direct or quasi-direct bandgap have an ultra-low exciton binding energy, which is favorable for separating electron and hole pairs. Moreover, these candidates possess high optical absorption in the visible light regions, and the power conversion efficiency limit of RCd3P3 series can be as high as 24.5 % at the thickness of 4 μm. These results could enrich the database of potential solar cells based on lanthanide materials.

Performance improvement of perovskite/CIGS tandem solar cell using barium stannate charge transport layer and achieving PCE of 39 % numerically

The way to overperform the Shockley-Quisser limit of power conversion efficiency (PCE) for single junction solar cell is tandem device. In this work, a perovskite solar cell (PSC) and Copper Indium Gallium Selenide (CIGS) based solar cell (CSC) are individually optimized and implemented as PSC/CSC tandem (PSSC) device in SCAPS-1D. The perovskites which are highly stable and optically fit for PSSC, consists of triple or quadruple mixed cations, lead (Pb) and halides and the most popular perovskite of this kind is Cs0.15MA0.15 FA0.70Pb(I0.85Br0.15)3 which is used as absorber material in the PSC presented in this work. Another important aspect of PSC is selection of suitable material for charge transport layers. For the first time, a never explored before the oxide perovskite namely the barium stannate (BaSnO3) is used as electron transport layer (ETL) along with NiO as hole transport layer (HTL) in the reported PSC which provides impressive short circuit current density (JSC), open circuit voltage (VOC), fill-factor (FF) and PCE of 23.89 mAcm−2, 1.48 V, 88.92 %, 31.53 % respectively. Moreover, a comprehensive analysis of the PSC without HTL but with BaSnO3 as ETL is carried out and improved records are observed. Finally, the optimized PSSC which consists of HTL free PSC and CSC can deliver a PCE as high as 39 % which is the highest ever predicted value and is attributed to the well-matched energy band alignment of BaSnO3 with the absorber. This work can be a potential contributor to the high efficiency solar cell fabrication roadmap.

Magnetic-linkage nonlinear piezoelectric energy harvester with time-varying potential wells: Theoretical and experimental investigations

Energy harvesting has emerged as a prospective solution for powering wireless sensors on the Internet of Things (IoT). However, the limited energy conversion efficiency remains a significant challenge, thereby hindering the feasibility of self-powered sensing in IoT. To address this issue, this paper proposes a magnetic-linkage nonlinear piezoelectric energy harvester (PEH) capable of effectively operating over a wide frequency bandwidth, particularly under low-level base excitations. The proposed PEH comprises one vertical and two horizontal piezoelectric beams, which are coupled by the magnetic force to realize the magnetic-linkage effect and create time-varying potential wells. A comprehensive theoretical model has been developed to reveal the working mechanisms of the magnetic-linkage effect and corresponding time-varying potential wells. Based on these foundations, theoretical results indicate that the magnetic configuration parameters have a significant impact on the magnetic-linkage effect and potential barriers. In addition, experimental investigations indicate that the magnetic-linkage effect broadens the effective frequency bandwidth, leading to a significant improvement in energy harvesting efficiency of up to 400% compared to the PEH without magnetic-linkage effect. Furthermore, the proposed PEH enables the realization of self-powered sensing in experiments. In summary, by exploiting the magnetic-linkage effect to create the time-varying potential wells, this innovative approach holds a great promising application for achieving high-efficiency energy harvesting from low-level environmental vibrations.

Feasibility study on energy harvesting with thermoelectric generators in a photovoltaic-ground source heat pump system

Thermoelectric generators (TEGs) harness temperature differences to produce electricity and hold promise for diverse industrial applications. However, their limited conversion efficiency casts doubt on their role in achieving energy independence. This study introduces an advanced technique that exploits temperature gradients in water pipes, utilizing supplementary TEGs to augment power generation. This method maintains a stable temperature gradient for TEG operation. Additionally, TEG power output can be efficiently modulated via flow control. In the feasibility evaluation for residential settings, the temperature fluctuations across each system unit were analyzed. In the active system, the chosen sites for TEG integration were units equipped to manage heat transfer using working fluids. The inlet and outlet temperatures were calculated for photovoltaic-thermal (PVT) systems, ground heat exchangers (GHEs), and heat storage tanks (HSTs). The electricity produced by the TEGs was benchmarked against their conversion efficiency, zT. The results indicated that the TEGs yielded 10.95 kWh of electricity when systematically implemented in each unit. To realize a zero-energy building, an area of 64.5 m2 per unit is necessitated for TEG deployment, given a zT value of 1.

Optical–electrical simulation and optimization of an efficient lead-free 2T all perovskite tandem solar cell

The characteristics of a lead-free all perovskite tandem solar cell (P-TSC) are studied in this study. All P-TSCs were developed with the goal of breaking through the theoretical power conversion efficiency (PCE) limit for single-junction (SJ) perovskite solar cells (PSCs) established by Shockley and Queisser. Solving the toxicity problem in lead-containing sub-cells is essential for the continued growth of all P-TSCs. Here, we first present a coupled three-dimensional (3D) optical–electrical simulation of two lead-free SJ MAGeI3(Eg=1.9eV) and MASnI3(Eg=1.3eV) PSCs. The results showed that the PCE of the SJ-wide bandgap (WBG) and SJ-narrow bandgap (NBG) PSCs is 19.59% and 15.57%, respectively. Next, a two-terminal (2T) eco-friendly all P-TSC with combines these two solar cells has been designed, where the MAGeI3-PSC serves as the top sub-cell and the MASnI3-PSC serves as the bottom sub-cell. By establishing the current matching condition between two sub-cells in the 2T structure, the matched short-circuit current density (Jsc) and PCE are obtained 12.30mA/cm2 and 28.46%, respectively. Herein, a 299 nm-thick NBG-absorber layer and a 200 nm-thick WBG-absorber layer are required. In order to increase the matched Jsc and PCE and decrease the required NBG-absorber layer thickness, the parasitic absorption and reflection losses are minimized by selecting the best materials for the transparent conductive oxide (TCO) front contact and interconnecting (IC) layers, as well as the addition of an anti-reflection (AR) layer at the air/device interface as light management strategies. The results indicate that, under the current matching condition, improving the structure would lead to in a 76 nm reduction in the NBG-absorber layer’s required thickness and a 16.44% increase in PCE. Finally, we suggested the optimized 2T non-Pb all P-TSC with a high PCE of 33.14% that is environmentally safe.

Practical efficiency limit of laser power converters based on lead halide perovskite

An ideal laser power converter (LPC) has a power conversion efficiency (PCE) limit of 100%; however, in a real device, additional losses degrade the PCE limit appreciably. We developed an approach to estimate the PCE of perovskite LPCs based on the state-of-the-art perovskite solar cells with a variety of losses. The practical PCE limit is found to be 60.2% under a 785 nm laser with power density of 50 mW/cm2, which result is corroborated by our experimentally measured PCE of 58.6%. Despite a comparable PCE to that of GaAs LPCs, the power output of current perovskite LPC is much lower due to the series resistance, which may be low enough for solar cells but needs to be reduced by one order of magnitude for LPCs. Moreover, the PCE can be further improved by confining emission angle and resorting to wider bandgap perovskite. Finally, a power output over 7 W/cm2 with PCE over 80% is estimated to be within reach for perovskite LPCs.

Performance enhancement of the combined power-refrigeration cycle using a liquid-gas-gas ejector for ocean thermal energy conversion

The practical implementation of ocean thermal energy conversion technology faces constraints due to the low temperature differentials, resulting in limited energy conversion efficiency. This research introduces a novel combined power-refrigeration cycle that utilizes a hybrid liquid-gas-gas ejector to amplify the conversion efficiency. The gas extracted from the turbine is employed as auxiliary fluid within the liquid-gas-gas nozzle, effectively countering the low ejection coefficient associated with conventional liquid-gas ejectors. To elucidate the mechanism behind the liquid-gas-gas ejection process involving an ammonia-water-based absorption working fluid, a comprehensive fluid flow model for ejector is developed. This model facilitates the clarification of the non-equilibrium phase transition process occurring within the ejector. Parametric analysis was conducted to assess cycle performance under various operating conditions. The results show the innovative cycle can attain power/refrigeration efficiencies of 1.58 %/17.45 % while maintaining a refrigeration temperature of −18 °C. Performance comparisons indicate that the proposed liquid-gas-gas ejector based cycle reduces the minimum refrigeration temperature by 20.5 % in contrast to the cycle employing only the liquid-gas ejector, all while preserving power output. Furthermore, despite a mere 26 °C temperature difference, the refrigeration capacity of this cycle significantly outperforms those operating at greater temperature differentials. These findings demonstrate a substantial enhancement in the refrigeration and power capabilities of ocean thermal energy conversion.

High‐Speed Deposition of Large‐Area Narrow‐Bandgap Perovskite Films for All‐Perovskite Tandem Solar Mini‐Modules

AbstractDeveloping all‐perovskite tandem solar cells is an effective approach to extend the limit of power conversion efficiency. However, fast preparation of large‐area and high‐quality narrow‐bandgap Sn‐based perovskite films still remains a major challenge in fabricating all‐perovskite tandem modules. Here high‐crystalline and compact narrow‐bandgap perovskite films with an area over 100 cm2 are well prepared by combining compositional, solvent and additive engineering. The use of 2‐methoxyethanol as a solvent enables the fast deposition of narrow‐bandgap perovskite films. Adding proper amounts of dimethyl sulfoxide and surfactant L‐α‐phosphatidylcholine into the narrow‐bandgap perovskite precursor effectively enhances the crystallinity and coverage of the resulting perovskite films, respectively. Based on these studies, narrow‐bandgap perovskite and all‐perovskite tandem mini‐modules with an aperture area of 10.4 cm2 are constructed and exhibit high efficiencies of 13.2% and 16.4%, respectively. This study provides an option for fast deposition of high‐quality narrow‐bandgap perovskite films, which is beneficial for the scalable production of all‐perovskite tandem solar modules.

Optically pumped Milliwatt Whispering-Gallery microcavity laser

Whispering-gallery-mode microcavity lasers possess remarkable characteristics such as high Q factors and compact geometries, making them an essential element in the evolution of microlasers. However, solid-state whispering-gallery-mode lasers have previously suffered from low output power and limited optical conversion efficiency, hindering their applications. Here, we present the achievement of milliwatt laser emissions at a wavelength of 1.06 µm from a solid-state whispering-gallery-mode laser. To accomplish this, we construct a whispering-gallery-mode microcavity (with a diameter of 30 µm) using a crystalline Nd: YAG thin film obtained through carbon-implantation enhanced etching of a Nd: YAG crystal. This microcavity laser demonstrates a maximum output power of 1.12 mW and an optical conversion efficiency of 12.4%. Moreover, our unique eccentric microcavity design enables efficient coupling of free-space pump light, facilitating integration with a waveguide. This integration allowed for single-wavelength laser emission from the waveguide, achieving an output power of 0.5 mW and an optical conversion efficiency of 6.18%. Our work opens up new possibilities for advancing solid-state whispering-gallery-mode lasers, providing a viable option for compact photonic sources.

Synergistic Effect of Size-Tailored Structural Engineering and Postinterface Modification for Highly Efficient and Stable Dye-Sensitized Solar Cells.

Despite significant progress in device performance, dye-sensitized solar cells (DSSCs) continue to fall short of their theoretical potential. Moreover, research in recent years needs to pay more attention to improving the device fabrication process. To achieve the theoretical efficiency limit, it is crucial to optimize the interface between the dye and TiO2 nanoparticles in the entire device stack. Our study indicates that optimizing the structure or size of the coadsorbents and implementing a monolayer adsorption process can be an effective strategy to reduce charge recombination and enhance light-harvesting properties. Our research aims to develop a surface-coating adsorbent plan that controls the TiO2 nanoparticle interface to achieve the radiative limit of power conversion efficiency (PCE). Specifically, we utilized 2-thiophenecarboxylic acid (THCA) or chenodeoxycholic acid (CDCA) as postinterfacial surface-coating adsorbents. Our results demonstrate that this approach effectively achieves the desired PCE limit. Combined with the coadsorbent structure engineering and interface optimization, the device increased the packing area on the TiO2 nanoparticles' surface, reaching an improved PCE of over 13.17% under simulated sunlight (1.5G), which is the highest efficiency of a porphyrin single dye-based DSSC. In particular, this practical approach was also applied to a large-area DSSC with an area of 3 cm2, yielding a remarkable PCE of 9.04%. Furthermore, when applied to a polymer gel electrolyte, this novel approach recorded the highest PCE of 11.16% with a long-term operational stability of up to 1000 h for the quasi-solid-state DSSCs. Our research findings provide a promising avenue for achieving high-performance DSSCs with ease of access and demonstrate practical applications as alternatives to conventional power sources.

Synergy of Light Trapping and Water Management in Interconnected Porous PEDOT:PSS Hydrogels for Efficient Solar-Driven Water Purification

Interfacial solar water purification is emerging as a sustainable and environmental-friendly approach for solar energy harvesting and clean water production. Currently, the limited photothermal conversion efficiency restricts its practical applications. Developing evaporators with porous structures has been proposed as a promising way toward boosting solar-thermal-vapor conversion by enhancing energy utilization and evaporation area. However, effective collaboration between light capture and water management of porous evaporators is the main challenge for efficient freshwater production. Here, we reported a pure poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrene sulfonate (PSS) hydrogel by in situ polymerization as a solar evaporator for water purification from saline water or wastewater. The interconnected and microporous structure of the PEDOT:PSS hydrogel (PPH) can dramatically trap light throughout broad incident angles as well as increase the active water content simultaneously, which is highly controlled by the PSS content. The PPH could efficiently convert the absorbed solar energy and wastewater into fresh water, thus leading to an excellent photothermal conversion efficiency of 96.4% and an evaporation rate of 2.43 kg·m–2·h–1 during purification of 3.5 wt % NaCl brine under one sun irradiation. This PPH exhibits sustainable and stable performance in 88 h when purified with 3.5 wt % simulated saline water, with an evaporation rate of ∼2.32 kg·m–2·h–1. What is more, this PPH performs satisfied performance in water purification (with the concentration of all ions dropping below 1 mg·L–1) from saline water, dye, and heavy metal wastewater. These results demonstrate that high evaporation performance could be achieved if effective light trapping and water management are ensured simultaneously. Thus, this study provides a new possibility for long-term, stable, and efficient water purification from wastewater.