Conversion Efficiency Research Articles

Optimizing small-scale power generation: Exergetic and exergoeconomic evaluation of an integrated gasification system for sacha inchi residues

Biomass is the primary non-fossil energy source, especially in regions such as Central and South America, and holds immense potential for non-fossil energy. Utilizing waste biomass, mainly through gasification for syngas production, offers environmental advantages over direct combustion for electricity and heating. The sacha inchi seed shell (SIS), currently discarded, presents an untapped biomass resource. Hence, the significance of this work lies in assessing the gasification potential of SIS for decentralized power generation, targeting rural off-grid areas. Detailed modeling of mass, energy, and exergy flows was used to establish a self-sustaining 35 kW sacha inchi processing plant using Aspen Plus software. The best operational condition was identified at an equivalence ratio of 0.25, achieving 100 % carbon conversion efficiency and 73.5 % cold gas efficiency with a lower heating value of 6.126 MJ/kg. Exergetic analysis highlights heat exchangers and the power generator as the least efficient components (0.214 % to 27.85 %), contrasting with superior efficiencies in the gasifier, compressor, and cyclone (82.85 %, 85.5 %, and 96.13 %, respectively). Exergoeconomic assessment reveals an energy cost of 10.25 USD/GJ, notably lower than Colombian energy costs for equivalent power needs.

Analysis of efficiency and influencing factors of knowledge services in public libraries: the evidence from China

PurposeThe purpose of this study is to quantify and evaluate the efficiency of knowledge services public libraries (PLKS) in China and to analyze the factors affecting the efficiency of PLKS. The focus of this study is to explore the characteristics and changing trends of PLKS and how to improve the efficiency of PLKS. The conclusions drawn in this paper are expected to provide important references for academic research and practical exploration in related fields.Design/methodology/approachThis study constructs a three-stage process of PLKS. On this basis, the efficiency is analyzed by using the Super-NSBM model, and the influencing factors of PLKS are analyzed by using OLS. Finally, through the comprehensive interpretation of the measured data and the existing social development conditions, the authors put forward relevant recommendations.FindingsIn the first stage, the PLKS in China meets the basic requirements, but there is an obvious waste of resources in the second stage. In addition, China’s public libraries show obvious regional differences in knowledge service efficiency. Finally, it was found that economic and technological factors can increase the efficiency of PLKS, but the increase in the number of university students will reduce the efficiency of PLKS.Originality/valueIn this study, the authors provide an exhaustive deconstruction and explanation of PLKS, which leads to the proposal of a three-stage PLKS efficiency conversion process. Furthermore, the authors identify a diverse set of quantifiable metrics that are readily accessible for open collection. Notably, the authors correlated the efficiency of PLKS with the influencing factors, exploring PLKS from a new perspective and enriching the research related to PLKS.

Efficient conversion of distillers grains as feed ingredient by synergy of probiotics and enzymes

Efficient conversion of distillers grains as feed ingredient by synergy of probiotics and enzymes

Enhanced photothermoelectric conversion in self-rolled tellurium photodetector with geometry-induced energy localization

Photodetection has attracted significant attention for information transmission. While the implementation relies primarily on the photonic detectors, they are predominantly constrained by the intrinsic bandgap of active materials. On the other hand, photothermoelectric (PTE) detectors have garnered substantial research interest for their promising capabilities in broadband detection, owing to the self-driven photovoltages induced by the temperature differences. To get higher performances, it is crucial to localize light and heat energies for efficient conversion. However, there is limited research on the energy conversion in PTE detectors at micro/nano scale. In this study, we have achieved a two-order-of-magnitude enhancement in photovoltage responsivity in the self-rolled tubular tellurium (Te) photodetector with PTE effect. Under illumination, the tubular device demonstrates a maximum photovoltage responsivity of 252.13 V W−1 and a large detectivity of 1.48 × 1011Jones. We disclose the mechanism of the PTE conversion in the tubular structure with the assistance of theoretical simulation. In addition, the device exhibits excellent performances in wide-angle and polarization-dependent detection. This work presents an approach to remarkably improve the performance of photodetector by concentrating light and corresponding heat generated, and the proposed self-rolled devices thus hold remarkable promises for next-generation on-chip photodetection.

Size Dependence of Ultrafast Electron Transfer from Didodecyl Dimethylammonium Bromide-Modified CsPbBr3 Nanocrystals to Electron Acceptors.

Charge transfer efficiencies in all-inorganic lead halide perovskite nanocrystals (NCs) are crucial for applications in photovoltaics and photocatalysis. Herein, CsPbBr3 NCs with different sizes are synthesized by varying the ligand contents of didodecyl dimethylammonium bromide at room temperature. Adding benzoquinone (BQ) molecules leads to a decrease in the PL intensities and PL decay times in NCs. The electron transfer (ET) efficiency (ηET) increases with NC size in complexes of CsPbBr3 NCs and BQ molecules (NC-BQ complexes), when the same concentration of BQ is maintained, as investigated by transient photobleaching and photoluminescence spectroscopies. Controlling the same number of attached BQ acceptor molecules per NC induces the same ηET in NC-BQ complexes even though with different NC sizes. Our findings provide new insights into ultrafast charge transfer behaviors in perovskite NCs, which is important for designing efficient light energy conversion devices.

Activation of MOF Catalysts with Low Steric Hindrance via Undercoordination Chemistry for Efficient Polysulfide Conversion in Lithium–Sulfur Battery

AbstractLithium–sulfur (Li–S) batteries promise high theoretical energy density and cost‐effectiveness but grapple with challenges like the polysulfide shuttle effect and sluggish kinetics. Metal–organic framework (MOF) catalysts emerge as a leading solution, despite limited conductivity and high steric hindrance. This study employs undercoordination chemistry to modify Zn–Co bimetallic MOFs (D‐ZIF L), removing organic ligands from active centers. This process mitigates spatial hindrance, thereby promoting comprehensive contact between sulfur species and metal active centers, consequently enhancing the catalytic efficiency of MOFs. Moreover, undercoordination treatment of the metal active centers induces electron redistribution, augmenting electron density at the Fermi level of the metal elements, thereby ameliorating the intrinsic conductivity. Leveraging these advantages, fabricated Li–S batteries employing D‐ZIF L catalysts exhibited markedly mitigated shuttling effects and accelerated sulfur species conversion kinetics. Notably, a substantial reverse areal capacity of 5.0 mAh cm⁻2 is achieved after 100 cycles with an evaluated sulfur loading of 5.5 mg cm⁻2. Furthermore, a practical pouch cell demonstrated an initial capacity of 1.8 Ah at 85.8 mA with stable cycling for 50 cycles. This study underscores the potential of undercoordination chemistry in the development of highly conductive MOF catalysts with minimized steric hindrance, thereby advancing the prospects of Li–S battery technology.

Fully-Fused Indacenodithiophene-Centered Small Molecule n-Type Semiconductors for High-Performance Organic Electronics.

Developing novel n-type organic semiconductors is an enduring research endeavour, given their pivotal roles in organic electronics and their relative scarcity compared to p-type counterparts. In this study, a new strategy was employed to synthesize n-type organic semiconductors featuring fully-fused conjugated backbone. By attaching two sets of adjacent amino and formyl groups to the indacenodithiophene-based central cores and triggering a tandem reaction of Knoevenagel condensation-intramolecular cyclization, DFA1 and DFA2 were realized. The solution-processed organic field effect transistors based on DFA1 exhibited unipolar n-type transport character with a decent electron mobility of ca. 0.10 cm2 V-1 s-1 (ca. 0.038 cm2 V-1 s-1 for DFA2 based devices). When employing DFA1 as a third component in organic solar cells, a high power conversion efficiency of 19.2% can be achieved in ternary devices fabricated with PM6:L8-BO:DFA1. This work paves a new pathway in the molecular engineering of n-type organic semiconductors, propelling relevant research forward.

Catalytic Dechlorination of Three Organochlorides by Recyclable Nano-Palladium-Engineered Natural Sponge with Formic Acid

Catalytic dechlorination of organic chlorides by palladium (Pd) with HCOOH represents one of the most effective and promising techniques for environmental remediation. In this study, we adopted alkaline-modified porous natural sponge as support of a Pd nanocatalyst (Pd@M-Sponge) and HCOOH as a hydrogen source for the hydrodechlorination of florfenicol (FF), o-chlorophenol (o-CP), and p-chlorophenol (p-CP). Favorable conversion efficiency of FF, o-CP, and p-CP was achieved at 25 °C and atmospheric pressure attributed to the small diameter and high catalytic reactivity of the prepared Pd NPs, in addition to the slight internal mass transfer limitation of the prepared Pd@M-Sponge. High reaction rate constants were obtained even in the conditions of a low molar ratio of HCOOH to p-CP (10:1) and a high concentration of p-CP (500 mg/L). The prepared catalyst also demonstrated superior recyclability without any obvious decrease in catalytic reactivity in 20 successive p-CP dechlorination cycles. This work provides an ideal recyclable and cost-effective catalyst based on renewable and biocompatible natural material for the catalytic hydrodechlorination of chlorinated organic pollutants with formic acid and a new view for the exploration and designing of highly reactive and stable catalysts for hydrodechlorination.

Fully‐Fused Indacenodithiophene‐Centered Small Molecule n‐Type Semiconductors for High‐Performance Organic Electronics

Developing novel n‐type organic semiconductors is an enduring research endeavour, given their pivotal roles in organic electronics and their relative scarcity compared to p‐type counterparts. In this study, a new strategy was employed to synthesize n‐type organic semiconductors featuring fully‐fused conjugated backbone. By attaching two sets of adjacent amino and formyl groups to the indacenodithiophene‐based central cores and triggering a tandem reaction of Knoevenagel condensation‐intramolecular cyclization, DFA1 and DFA2 were realized. The solution‐processed organic field effect transistors based on DFA1 exhibited unipolar n‐type transport character with a decent electron mobility of ca. 0.10 cm2 V‐1 s‐1 (ca. 0.038 cm2 V‐1 s‐1 for DFA2 based devices). When employing DFA1 as a third component in organic solar cells, a high power conversion efficiency of 19.2% can be achieved in ternary devices fabricated with PM6:L8‐BO:DFA1. This work paves a new pathway in the molecular engineering of n‐type organic semiconductors, propelling relevant research forward.

Optimizing Crystal Orientation and Defect Mitigation in Antimony Selenide Thin-Film Solar Cells through Buffer Layer Energy Band Adjustment.

Antimony selenide (Sb2Se3) has sparked significant interest in high-efficiency photovoltaic applications due to its advantageous material and optoelectronic properties. In recent years, there has been considerable development in this area. Nonetheless, defects and suboptimal [hk0] crystal orientation expressively limit further device efficiency enhancement. This study used Zinc (Zn) to adjust the interfacial energy band and strengthen carrier transport. For the first time, it is discovered that the diffusion of Zn in the cadmium sulfide (CdS) buffer layer can affect the crystalline orientation of the Sb2Se3 thin films in the superstrate structure. The effect of Zn diffusion on the morphology of Sb2Se3 thin films with CdxZn1-xS buffer layer has been investigated in detail. Additionally, Zn doping promotes forming Sb2Se3 thin films with the desired [hk1] orientation, resulting in denser and larger grain sizes which will eventually regulate the defect density. Finally, based on the energy band structure and high-quality Sb2Se3 thin films, this study achieves a champion power conversion efficiency (PCE) of 8.76%, with a VOC of 458mV, a JSC of 28.13mA cm-2, and an FF of 67.85%. Overall, this study explores the growth mechanism of Sb2Se3 thin films, which can lead to further improvements in the efficiency of Sb2Se3 solar cells.

Photothermal Depth Profiling of Gelatin-Stabilised Gold Nanorods-Trastuzumab Conjugate as a Potential Breast Cancer Photothermal Agent

AbstractGold nanorods (AuNRs) are powerful photothermal agents (PTAs) in cancer treatment due to their near-infrared laser light absorption ability. However, the cytotoxicity of AuNRs caused by the presence of cationic surfactants often used and their lack of specificity affect their application in photothermal therapy. Thus, we herein developed a bioconjugate obtained from the functionalisation of AuNRs to gelatin (Gel@AuNRs), followed by the conjugation of the as-synthesised material to a breast cancer antibody, trastuzumab (Trast-Gel@AuNRs) to address these issues. The optical and structural characterization of the as-synthesized indicated no significant changes in the optical properties of AuNRs after their functionalisation with gelatin and conjugation with the antibody. The photothermal profiling of the as-synthesised materials showed that AuNRs still have an excellent photothermal conversion efficiency (PCE) after their functionalisation (20%) and their conjugation to an antibody (19%). In addition, the In vitro photothermal depth response showed that Trast-Gel@AuNRs is a promising photothermal agent for HER2-positive breast cancer treatment. Graphical Abstract

High-Performance PM6:Y6-Based Ternary Solar Cells with Enhanced Open Circuit Voltage and Balanced Mobilities via Doping a Wide-Band-Gap Amorphous Acceptor.

Great progress has been made in organic solar cells (OSCs) in recent years, especially after the report of the highly efficient small-molecule electron acceptor Y6. However, the relatively low open circuit voltage (VOC) and unbalanced charge mobilities remain two issues that need to be resolved for further improvement in the performance of OSCs. Herein, a wide-band-gap amorphous acceptor IO-4Cl, which possessed a shallower lowest unoccupied molecular orbital (LUMO) energy level than Y6, was introduced into the PM6:Y6 binary system to construct a ternary device. The mechanism study revealed that the introduced IO-4Cl was alloyed with Y6 to prevent the overaggregation of Y6 and offer dual channels for effective hole transportation, resulting in balanced hole and electron mobilities. Taking these advantages, an enhanced VOC of 0.894 V and an improved fill factor of 75.58% were achieved in the optimized PM6:Y6:IO-4Cl-based ternary device, yielding a promising power conversion efficiency (PCE) of 17.49%, which surpassed the 16.72% efficiency of the PM6:Y6 binary device. This work provides an alternative solution to balance the charge mobilities of PM6:Y6-based devices by incorporating an amorphous high-performance LUMO A-D-A small molecule as the third compound.

Assessment of NIR-triggered PEG-coated NaGdF4:Tm3+/Yb3+ bio-compatible upconversion nanoparticles for contrast enhancement in OCT imaging and optical thermometry

In this investigation, we embarked on the synthesis of polyethylene glycol coated NaGdF4:Tm3+/Yb3+ upconversion nanoparticles (UCNPs), aiming to assess their utility in enhancing image contrast within the context of swept source optical coherence tomography (OCT) and photo-thermal OCT imaging. Our research unveiled the remarkable UC emissions stemming from the transitions of Tm3+ ions, specifically the 1G4 → 3H6 transitions, yielding vibrant blue emissions at 472 nm. We delved further into the UC mechanism, meticulously scrutinizing decay times and the nanoparticles′ capacity to convert radiation into heat. Notably, these nanoparticles exhibited an impressive photo-thermal conversion efficiency of 37.5%. Furthermore, our investigations into their bio-compatibility revealed a promising outcome, with more than 90% cell survival after 24 h of incubation with HeLa cells treated with UCNPs. The nanoparticles demonstrated a notable thermal sensitivity of 4.7 × 10−3 K−1 at 300 K, signifying their potential for precise temperature monitoring at the cellular level.

Interfacial Crosslinking for Efficient and Stable Planar TiO2 Perovskite Solar Cells.

The buried interface between the electron transport layer (ETL) and the perovskite layer plays a crucial role in enhancing the power conversion efficiency (PCE) and stability of n-i-p type perovskite solar cells (PSCs). In this study, the interface between the chemical bath deposited (CBD) titanium oxide (TiO2) ETL and the perovskite layer using multi-functional potassium trifluoromethyl sulfonate (SK) is modified. Structural and elemental analyses reveal that the trifluoromethyl sulfonate serves as a crosslinker between the TiO2 and the perovskite layer, thus improving the adhesion of the perovskite to the TiO2 ETL through strong bonding of the ─CF3 and ─SO3 - terminal groups. Furthermore, the multi-functional modifiers reduced interface defects and suppressed carrier recombination in the PSCs. Consequently, devices with a champion PCE of 25.22% and a fill factor (FF) close to 85% is achieved, marking the highest PCE and FF observed for PSCs based on CBD TiO2. The unencapsulated device maintained 81.3% of its initial PCE after operating for 1000 h.

An Intramolecular Rotor-Bridged Dimeric Cyanine Photothermal Transducer for Efficient Near-Infrared II Fluorescence Imaging-Guided Mitochondria-Targeted Phototherapy.

Near-infrared (NIR) heptamethine cyanine (HCy) dyes are promising photothermal transducers for image-guided cancer treatment owing to their prominent photophysical properties and high photothermal conversion ability. However, HCy photothermal transducers usually have poor photostability due to degradation induced by the self-generated reactive oxygen species. Herein, a novel mitochondria-targeting dimeric HCy dye, named dimeric oBHCy, is rationally designed, exhibiting strong near-infrared II (NIR-II) fluorescence emission, high photothermal conversion efficiency (PCE), and excellent photostability. The large π-conjugation and drastic intramolecular motion of the diphenol rotor in the dimeric oBHCy enhance the nonradiative energy dissipation and suppress the intersystem crossing process, thereby achieving a high PCE (49.2%) and improved photostability. Impressively, dimeric oBHCy can precisely target mitochondria and induce mitochondrial damage upon NIR light irradiation. Under the guidance of in vivo NIR-II fluorescence imaging, efficient NIR light-activated photothermal therapy of 4T1 breast tumors is accomplished with a tumor inhibitory rate of 96% following a single injection of the dimeric oBHCy. This work offers an innovative strategy for designing cyanine photothermal transducers with integrated NIR-II fluorescence and photothermal properties for efficient cancer theranostics.

The g-C3N4/CdO heterojunction as an efficient photo-electron catalyst for hydrogen production

The electronic, optical, and photo-electro catalytic properties of the g-C3N4/CdO(CGN/CdO) heterojunction are studied by Density Functional Theory (DFT) calculations. The CGN/CdO heterojunction has a staggered band structure and indirect bandgap (1.976 eV), following the S-scheme mechanism. The absorption spectra of the heterojunction are substantially red-shifted and the absorption coefficients are significantly higher relative to the intrinsic g-C3N4(GCN) and intrinsic CdO. In addition, the power conversion efficiency (PCE) is 14.21 %. The photo-catalytic water decomposition can occur at pH = 0–14. The ηSTH of the GCN/CdO heterojunction is up to 31.82 %, and it is modulated to 36.14 % under −4 % biaxial strain modulation. The low over-potential of the Oxygen evolution reaction (OER) for the heterojunction is 0.905 V obtained at the GCN layer, and that of the Hydrogen evolution reaction (HER) is −0.498 V occurred at the CdO layer. These findings suggest that the GCN/CdO heterojunction has an efficient photo-electro catalytic potential for hydrogen production.

Solar collector inspired by the polar bear: Fluorescent‐reinforcing photothermal conversion efficiency

AbstractThe crucial point of solar thermal utilization makes solar heat collector gathering much attention. In this study, imitating polar bears' fur structure, fluorescent materials are modified into a solar heat collector, and the photothermal conversion is evaluated to examine the influence of polyvinyl alcohol concentration, fluorescent luminescence type and fluorescence concentration. The test results indicate that fluorescent materials that has a greater Stokes shift show the greater photothermal effect. Moreover, when composed of a PVA concentration being 5.0% and a fluorescent concentration being 0.50%, the composites exhibit the maximal photothermal conversion temperature (99.4°C) that is 17.9% higher than that of the solar heat collectors without fluorescent materials. This study proposes creating solar heat collector with modified fluorescent materials, and the new perspective of which demonstrates that the composites have a great potential and application prospect in the solar photothermal field.

"Coir Raincoat"-Boosted Biomimetic Hydrogel for Efficient Solar Desalination and Wastewater Purification.

Solar-driven interfacial evaporation is an efficient method for purifying contaminated or saline water. Nonetheless, the suboptimal design of the structure and composition still necessitates a compromise between evaporation rate and service life. Therefore, achieving efficient production of clean water remains a key challenge. Here, a biomimetic dictyophora hydrogel based on loofah/carbonized sucrose@ZIF-8/polyvinyl alcohol is demonstrated, which can serve as an independent solar evaporator for clean water recovery. This special structural design achieves effective thermal positioning and minimal heat loss, while reducing the actual enthalpy of water evaporation. The evaporator achieves a pure water evaporation rate of 3.88kg m-2 h-1 and a solar-vapor conversion efficiency of 97.16% under 1 sun irradiation. In comparison, the wastewater evaporation rate of the evaporator with ZIF-8 remains at 3.85kg m-2 h-1 for 30 days, which is 16.3% higher than the light irradiation without ZIF-8. Equally important, the evaporator also showcases the capability to cleanse water from diverse sources of contaminants, including those with small molecules, oil, heavy metal ions, and bacteria, greatly improving the lifespan of the evaporator.

Tungsten-Doped ZnO as an Electron Transport Layer for Perovskite Solar Cells: Enhancing Efficiency and Stability.

This study delves into enhancing the efficiency and stability of perovskite solar cells (PSCs) by optimizing the surface morphologies and optoelectronic properties of the electron transport layer (ETL) using tungsten (W) doping in zinc oxide (ZnO). Through a unique green synthesis process and spin-coating technique, W-doped ZnO films were prepared, exhibiting improved electrical conductivity and reduced interface defects between the ETL and perovskite layers, thus facilitating efficient electron transfer at the interface. High-quality PSCs with superior ETL demonstrated a substantial 30% increase in power conversion efficiency (PCE) compared to those employing pristine ZnO ETL. These solar cells retained over 70% of their initial PCE after 4000 h of moisture exposure, surpassing reference PSCs by 50% PCE over this period. Advanced numerical multiphysics solvers, employing finite-difference time-domain (FDTD) and finite element method (FEM) techniques, were utilized to elucidate the underlying optoelectrical characteristics of the PSCs, with simulated results corroborating experimental findings. The study concludes with a thorough discussion on charge transport and recombination mechanisms, providing insights into the enhanced performance and stability achieved through W-doped ZnO ETL optimization.

Thermoelectric response in zigzag chains: Impact of irradiation-induced conformational changes

This study explores the enhancement of thermoelectric response in a zigzag chain through irradiation with arbitrarily polarized light. The irradiation induces changes in hopping strengths, creating an asymmetric transmission profile around the Fermi energy, which is a crucial factor for achieving a higher figure of merit (FOM). Specific light configurations result in an FOM exceeding unity. We employ the Floquet–Bloch ansatz and minimal coupling scheme to model the irradiation effect, with transport properties evaluated using Green’s function technique within the Landauer–Büttiker formalism. The investigation covers electrical conductance, thermopower, and thermal conductance due to electrons and phonons. Our research deepens understanding and opens avenues for tailoring nanostructures to fine-tune thermoelectric properties, advancing highly efficient energy conversion devices exploiting irradiation effects.