High Conversion Efficiency Research Articles

Isomeric diammonium passivation for perovskite-organic tandem solar cells.

In recent years, perovskite has been widely adopted in series-connected monolithic tandem solar cells (TSCs) to overcome the Shockley-Queisser limit of single-junction solar cells. Perovskite/organic TSCs, comprising a wide-bandgap (WBG) perovskite solar cell (pero-SC) as the front cell and a narrow-bandgap organic solar cell (OSC) as the rear cell, have recently drawn attention owing to the good stability and potential high power conversion efficiency (PCE)1,2,3,4. However, WBG pero-SCs usually exhibit higher voltage losses than regular pero-SCs, which limits the performance of TSCs5,6. One of the major obstacles comes from interfacial recombination at the perovskite/C60 interface, and it is important to develop effective surface passivation strategies to pursue higher PCE of perovskite/organic TSCs7. Here we exploit a new surface passivator cyclohexane 1,4-diammonium diiodide (CyDAI2), which naturally contains two isomeric structures with ammonium groups on the same or opposite sides of the hexane ring (denoted as cis-CyDAI2 and trans-CyDAI2, respectively), and the two isomers demonstrate completely different surface interaction behaviors. The cis-CyDAI2 passivation treatment reduces the Quasi-Fermi level splitting (QFLS)-open circuit voltage (Voc) mismatch of the WBG pero-SCs with a bandgap of 1.88 eV and enhanced its Voc to 1.36 V. Combining the cis-CyDAI2 treated perovskite and the organic active layer with a narrow-bandgap of 1.24 eV, the constructed monolithic perovskite/organic TSC demonstrates a PCE of 26.4% (certified as 25.7%).

Mode conversion in graded-index few-mode fiber via hollow cylindrical long-period fiber gratings.

We demonstrate the realization of mode conversion using hollow cylindrical long-period fiber gratings (LPFGs) inscribed in graded-index few-mode fibers (FMFs) by a femtosecond laser. By precisely shaping the refractive index modulation into a hollow cylindrical structure, we enable efficient coupling from the fundamental mode to high-order modes (LP11, LP02, LP21, LP12, LP31, LP03, and LP22 modes). The method achieves high-efficiency and low-loss mode conversion across various mode groups, marking a first for graded-index FMFs with different grating periods. The influence of the hollow cylindrical LPFG radius on mode conversion efficiency and spectral characteristics is thoroughly investigated. Additionally, incorporating a linear polarizer allowed for distinguishing between LP modes within a mode group, enhancing the tunability of the mode converter. These mode conversion devices have significant potential for applications in mode gain equalization and mode scrambling for mode division multiplexing (MDM) systems.

Characterizing temporal stability of supercontinuum generation in higher-order modes supported by liquid-core fibers

The generation of tailored supercontinua is essential for studying ultrafast light-matter interactions and for a variety of practical applications requiring broadband light. Liquid-core fibers (LCFs) have emerged as an innovative nonlinear photonic platform, demonstrating high efficiency in nonlinear frequency conversion. In this study, we showcase that LCFs provide a stable platform for ultrafast supercontinuum generation in a selected higher-order vector mode at 1.55μm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1.55\\;\\upmu \\hbox {m}$$\\end{document}. Specifically, we demonstrate soliton fission and double-dispersive wave generation using a radially polarized mode in a CS2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {CS}_{2}$$\\end{document}-silica liquid-core fiber. The experiments were performed in a temperature-controlled laboratory, showing excellent stability with no evidence of fiber degradation, material degradation, or drift-induced changes in mode excitation over extended periods under standard environmental conditions. Our results confirm that liquid-core fibers are a reliable platform for nonlinear photonics, suitable for applications such as computationally tailored supercontinuum generation, single pulse spxectroscopy, and tailored light sources, all of which rely on consistent and stable nonlinear frequency conversion.

Generating Immunological Memory Against Cancer by Camouflaging Gold-Based Photothermal Nanoparticles in NIR-II Biowindow for Mimicking T-Cells.

Photothermal therapy (PTT) against cancer not only directly ablates tumors but also induces tumor immunogenic cell death (ICD). However, the antitumor immune response elicited by ICD is insufficient to prevent relapse and metastasis because of the immunosuppressive tumor microenvironment (TME). A biomimetic nanoplatform (bmNP) mimicking cytotoxic lymphocytes (CTLs) for combinational photothermal-immunotherapy to effectively regulate the immunosuppressive TME is reported here. The bmNP is constructed by wrapping the T-cell membrane onto a new type of photothermal agents, spherical Au-based PNCs (sAuPNCs). Similar to T-cells, the bmNP enhanced accumulation at the tumor site by targeting the tumor via adhesion proteins on T-cell membrane. The obtained sAuPNCs have a wide absorption band in the second near-infrared (NIR-II) region with a high photothermal conversion efficiency (PCE) up to about 75% and excellent photostability. The bmNP with a smaller size is more superior compete with T-cells to bond with tumor cells via PD-1/PD-L1 interaction to effectively block the PD-1 checkpoint of T-cells for preventing T-cell exhaustion. Furthermore, in vivo studies reveal the immunological memory effect is significantly elicited in mice received bmNPs therapy. Collectively, bmNPs show great potential in photothermal-enhanced immunotherapy.

Rational Design of Facile and Low‐Cost Construction of Carbon‐Based Dye‐Sensitized Solar Cells using Garcinia Mangostana L. as a Photosensitizer

Research on solar cell devices is not only always related to how to obtain high power conversion efficiency (PCE), but also other factors need to be fully considered, such as the cost and their ecofriendliness. In this present research, a low‐cost and ecofriendly dye‐sensitized solar cell (DSSC) is being developed using a graphite‐based nanocomposite and an unusual plant extract (Garcinia mangostana L.) as the dye photosensitizer. A rational design on how to use graphite as a photoanode and counter electrode (CE) in DSSC is carried out by combining the graphite with ZnO and multiwalled carbon nanotube (MWCNT), respectively. It is observed that graphite acts as a matrix for ZnO and MWCNT to make these nanocomposites have very appropriate optoelectronics and catalytic properties compared to the control sample. Therefore, they could serve as an excellent photoanode and CE, respectively. It is also expected that the anthocyanin absorption in Garcinia mangostana L. dye which is found in the visible light range can efficiently absorb photons, thus supporting the enhancement of photovoltaic performance of the DSSC. The generated voltage (V) and current (I) from light irradiation using commercial lamps are higher compared to halogen lamps, indicating that the obtained DSSC has potential as indoor powered devices. It is believed that our study can shed light on the development of DSSC using low‐cost material graphite as the main component for the realization of low‐cost DSSC devices.

Research Progress on Photothermal Therapy of Malignant Tumor Cells

Malignant tumors, also known as cancer, are among the diseases with the highest incidence and mortality rates in the world. Photothermal therapy (PTT) involves injecting materials with high photothermal conversion efficiency (PTA) into the human body and using the principle of photothermal conversion to kill malignant tumor cells at the lesion site with high temperatures. This paper reviews various methods of photothermal therapy for malignant tumors, summarizes the basic therapeutic logic of photothermal therapy, and forecasts the future development prospects of this treatment method.

Anchoring ability and catalytic activity of B2C2 monolayer as the lithium-sulfur batteries cathode materials: A first principle calculation

Through first-principles calculation, the performance of B2C2 monolayer as the Li-S batteries cathode anchoring material is systematically investigated. The B2C2 monolayer exhibits excellent thermodynamic, kinetic and mechanical stability, which are helpful to resist the volume change caused by the reaction during charging and discharging process. Importantly, the adsorption energy of S8 clusters and LiPSs in the B2C2 monolayer is remarkably higher than that in the cathode electrolyte, which greatly inhibits the generation of shuttle effect. The calculations of the catalytic performance of B2C2 monolayer further suggest that the system possesses a lower the Gibbs free energy (ΔG) barrier of 0.71 eV and a fast kinetic conversion process with low diffusion barrier of 0.257 eV along hexatomic ring B2C4, implying a fast charge and discharge rate and excellent cycle performance. The B2C2 monolayer with high energy conversion efficiency and catalytic activity can be expected as an emerging sustainable clean energy source.

Fullerene‐Free p–i–n Perovskite Solar Cells: Direct Deposition of Tin Oxide on Perovskite Layer Using Ligand Bridges

AbstractIn p–i–n perovskite solar cells (PSCs), fullerene derivatives are predominantly used as an electron transport material (ETM) despite their disadvantages, such as parasitic absorption in the short wavelength range and high cost. State‐of‐the‐art n‐i‐p PSCs are fabricated using SnO2 as the ETM due to their high charge transfer ability, transparency, and low cost. However, in p–i–n PSCs, dispersing SnO2 nanoparticles in a solvent that does not damage the perovskite and forming a uniform layer is challenging. Herein, a strategy of directly depositing SnO2 quantum dots (QDs) on perovskite using ethylenediamine (EDA) for high‐performance applications is reported, which involves a SnO2 QD solution designed with a damage‐free cosolvent. Treating the SnO2 QD layer with the EDA strategy creates a conformal SnO2 QD layer and improves charge transport. This strategy achieves a high power conversion efficiency (PCE) of 18.9% in PSCs with a 1.77 eV bandgap, which is the highest PCE reported for wide bandgap p–i–n PSCs using an inorganic ETM. The top SnO2 layer enables ITO deposition without sputtering damage and achieves a bifacial factor of 99% due to the high transmittance of SnO2 QD. The resulting four‐terminal all‐perovskite tandem exhibited a PCE of 27.0%.

Rich-N highly branched COF loaded with imidazolyl ionic liquids for highly efficient catalysis of CO2 conversion under atmospheric pressure

The highly loaded ionic active centers and carbon dioxide (CO2) affinity sites play pivotal roles in catalyzing the gas-solid-liquid three-phase reaction in CO2 cycloaddition. In this study, a kind of rich-N highly branched Covalent organic framework loaded with imidazolyl ionic liquids (DhaTat-COF-IL) was synthesized through a nucleophilic substitution reaction, which bridged the highly loaded imidazolyl ionic liquids (Im-IL) active centers (20.72 %) and strong CO2-philic sites, efficiently promoting the in-situ of CO2 conversion at catalyst interface. The rich-N highly branched Covalent organic framework (DhaTat-COF) benefits from its abundant CO2-philic groups (imine and triazine groups) and microporous properties, exhibiting excellent CO2 enrichment capacity, designed as a porous crystalline material for anchoring high active Im-IL. The resultant DhaTat-COF-IL achieved a quantitative yield of 95 % (selectivity > 99 %) in converting epichlorohydrin (ECH) under ambient pressure at 80 ℃, with a turnover frequency (TOF) value reaching 1582 h⁻¹ at 120 ℃. Additionally, yields of ≥ 94 % were obtained for various terminal-substituted epoxides. Density Functional Theory (DFT) analysis reveals a synergistic effect between −CH and Br− in the DhaTat-COF-IL during catalytic cycling. This work provides valuable insights into the targeted design and performance optimization of Im-IL-grafted COF-based catalysts, emphasizing high efficiency and sustainability in CO₂ conversion.

A Prediction of All-Inorganic Lead-Free Halide Perovskites for Photovoltaic Application: Rb3Mo2Br9 and Rb3Mo2Cl9.

Lead-based organic-inorganic hybrid perovskites show promise as photovoltaic materials due to their high energy conversion efficiencies. However, concerns regarding lead toxicity and the poor environmental and operational stability of the organic cationic group have limited their widespread application. To address these challenges, the design of all-inorganic lead-free halide perovskites offers potential solutions for photovoltaic applications. Here, two layered perovskite derivatives, Rb3Mo2Cl9 and Rb3Mo2Br9, are explored, and their electronic, structural, and photovoltaic properties are analyzed using advanced theoretical calculations. Rb3Mo2Br9 exhibits a suitable direct bandgap of 1.60eV, making it a promising candidate for use as a light absorber in low-cost, high-efficiency solar cells. On the other hand, Rb3Mo2Cl9 demonstrates a wide direct bandgap exceeding 1.70eV, positioning it as a viable option for use as a top cell in tandem photovoltaic systems alongside silicon. Both materials display ideal optical properties in the visible light region and hold promise as excellent inorganic lead-free perovskite alternatives.

Readily constructed squaraine J-aggregates with an 86.0 % photothermal conversion efficiency for photothermal therapy

The development of photothermal agents with high photothermal conversion efficiency (PCE) and long absorption wavelengths is crucial for safe and effective anti-cancer treatment. However, achieving these advantages often requires precise molecular design and complex synthetic procedures. In this study, we present a simple, precise, and effective method for fabricating photothermal agents with high PCE using long wavelength excitation. This approach involves linking two electron-donating components, diphenylamine (DPA), and an electron-withdrawing squaraine (SQ), via a π-bridge thiophene (T). The resulting D-π-A-π-D structure leads to a red-shifted absorption band. Within the DTS structure, DPA functions as a molecular rotor, T serves as a coplanar backbone, and SQ promotes J aggregation. When DTS nanoparticles (NPs) are fabricated using an amphiphilic nano-carrier, the maximum absorption wavelength shifts from 701 to 803 nm. This shift is accompanied by reduced fluorescence and an exceptionally high PCE of 86.0 %. Both in vitro and in vivo assessments confirm that DTS NPs exhibit strong potential for photothermal antitumor therapy. Overall, this strategy offers a valuable framework for designing photothermal agents with clinical applications in mind, offering a simpler and more efficient approach to achieving high PCE and long absorption wavelengths.

Supramolecular Porphyrin Photosensitizers Based on Host-Guest Recognition for In Situ Bacteria-Responsive Near-Infrared Photothermal Therapy.

Antibiotic resistance resulting from the overuse of antibiotics sets a high challenge for brutal antimicrobial treatment. Although photothermal therapy (PTT) overcomes the awkward situation of antibiotic resistance, it usually mistakenly kills the beneficial bacteria strains when eliminating pernicious bacteria. Specifically recognizing and damaging the target pathogens is urgently required for PTT-mediated sterilization strategy. Based on the host-guest recognition between cucurbit[10]uril (CB[10]) and porphyrins, two water-soluble supramolecular porphyrins are designed and implement selective bactericidal effect via in situ bacteria-responsive near-infrared (NIR) PTT. With the help of CB[10], the π-π stacking and hydrophobic interactions of porphyrins are efficiently inhibited, thus contributing to a good photostability and a high photothermal conversion efficiency. Attributing to the matching reduction potential between facultative anaerobic Escherichia coli (E. coli) and porphyrins, they are selectively in situ reduced into supramolecular phlorin and supramolecular chlorin by E. coli, successfully achieving a selective sterilization against E. coli. In vivo, the in situ bacteria-responsive NIR PTT systems also promote the quick recovery of E. coli-infected abscesses and trauma on mice without inducing obvious systemic toxicity, providing a new alternative to the current antibiotics and helping relieve the global public health crisis of abusive antibiotics.

Enhancing light trapping for improved efficiency of perovskite solar cells: design and analysis

Abstract A hybrid organic-inorganic perovskite solar cells (PSCs) is explored for its potential to achieve high-efficiency and cost-effective solar energy conversion, especially through improved light management. In this paper, COMSOL Multiphysics is utilized to explore PSCs with light trapping nanostructures which will enhance the optical and electrical properties. A nanometer-scale concave structure is proposed in this paper to direct and capture light. This configuration is compared to a planar structure to see how it affect PSCs optoelectronic performance. Electrical simulations showed that concave nanostructured PSCs increase carrier generation and collect more carriers. The short-circuit current rose from 3.91 mA for the planar structure to 4.95 mA for the concave structure. Power conversion efficiency for concave PSCs increased 11% compared to the planar construction after choosing optimal height of concave structure. Thus, the performance investigation by combined optical and electrical analysis of nanostructures shows that it has the ability to build high-efficiency PSCs with light-trapping approach.

Enhanced high-harmonic generation in a polarization-insensitive all-dielectric metasurface exploiting dual-Fano resonance

Nonlinear optics demands efficacious techniques for nonlinear properties engineering. Metasurfaces, as a flat technology with easy fabrication in various arrangements and without the need for phase-matching conditions, are suitable platforms for nonlinear optics. This study proposes a silicon metasurface with special geometry that provides high conversion efficiency by exploiting Fano resonances and the excitation of magnetic and toroidal dipoles. The results indicate the high efficiencies of third harmonic generation of 5.17×10−3 W−2 and fifth harmonic generation of 7.92×10−9 W−4 under 1 GW/cm2 pump intensity in the near-infrared regime. More specifically, linear and nonlinear optical responses of the structure are completely polarization-independent.

Engineering Interfacial Molecular Interactions on Ag Hollow Fibre Gas Diffusion Electrodes for High Efficiency in CO2 Conversion to CO.

The electrochemical CO2 reduction reaction (CO2RR) occurs at the nanoscale interface of the electrode-electrolyte. Therefore, tailoring the interfacial properties in the interface microenvironment provides a powerful strategy to optimise the activity and selectivity of electrocatalysts towards the desired products. Here, the microenvironment at the electrode-electrolyte interface of the flow-through Ag-based hollow fibre gas diffusion electrode (Ag HFGDE) is modulated by introducing surfactant cetyltrimethylammonium bromide (CTAB) as the electrolyte additive. The porous hollow fibre configuration and gas penetration mode facilitate the CO2 mass transfer and the formation of the triple-phase interface. Through the ordered arrangement of hydrophobic long-alkyl chains, CTAB molecules at the electrode/electrolyte interface promoted CO2 penetration to active sites and repelled water to reduce the activity of competitive hydrogen evolution reaction (HER). By applying CTAB-containing catholyte, Ag HFGDE achieved a high CO Faradaic efficiency (FE) of over 95 % in a wide potential range and double the partial current density of CO. The enhancement of CO selectivity and suppression of hydrogen was attributed to the improvement of charge transfer and the CO2/H2O ratio enhancement. These findings highlight the importance of adjusting the local microenvironment to enhance the reaction kinetics and product selectivity in the electrochemical CO2 reduction reaction CO2RR.

Enhancing SrZrS3 perovskite solar cells: A comprehensive SCAPS-1D analysis of inorganic transport layers

In the quest for sustainable energy, perovskite solar cells have emerged as promising candidates due to their high power conversion efficiencies and excellent optoelectronic properties. This study focuses on SrZrS3, a lead-free chalcogenide perovskite, and its integration with various inorganic transport layers for enhanced photovoltaic performance. Using SCAPS-1D simulation software, the effects of different electron transport layers (ETLs) and hole transport layers (HTLs) on device efficiency were systematically explored. The device with a-Si:H as the HTL and ZnS as the ETL (aSi-3) shows the highest efficiency of 20.01 % resulting from better energy band alignment and reduced recombination losses. This study highlights the importance of optimizing transport layers for enhancing SrZrS3-based solar cells, offering insights for developing high-performance, lead-free perovskite solar cells.

Microenvironment regulation for high-performance acidic CO2 electroreduction on Poly(ionic liquid)-modified Cu surface

Electrocatalytic reduction of CO2 (CO2RR) under acidic conditions provides a feasible way for converting CO2 to multi-carbon products (C2+) with high feedstock conversion and high energetic efficiency (EE). In this work, poly(ionic liquid) (PIL)-Cu hybrids were employed as excellent acidic CO2RR electrocatalysts. A high faradaic efficiency towards C2+ products (FEC2+) of more than 61.0 % was achieved within a wide pH range from 2 to 14 at –700 mA cm–2. The optimum FEC2+ of 83.1 % was obtained at –700 mA cm–2 and pH = 2, corresponding to an EEC2+ of 37.6 %. By reducing the inlet CO2 flow rate to 1.59 mL min–1, a very high CO2 single-pass conversion of 98.7 % was achieved at –300 mA cm–2. The confinement of PIL layer caused by the semi-rigid abundant porous structure and dense cationic-anionic network enables the maintenance of a moderate local alkaline microenvironment and enrichment of K+ cations at the active sites. These effects jointly promote the C–C coupling at the Cu-PIL interface under acidic conditions. Remarkably, the CO2RR pathway can be regulated by functionality and morphology of the PIL layer.

The impact of interface and heterostructure on the stability of perovskite-based solar cells

Perovskite solar cells have made significant progress in achieving high power conversion efficiency (>26%) in the past decade. However, achieving long-term stability comparable to established silicon solar cells is still a significant challenge, requiring further investigation into degradation mechanisms and continued exploration of interface engineering strategies. Here we review stability at the interfaces between perovskite and charge transport layers. These interfaces are particularly vulnerable to defects and degradation under external stresses such as heat, light, and bias, further compounded by their ionic nature and thermal expansion mismatch. To address these issues, strategies such as the use of additives, organic self-assembled monolayers, and low-dimensional perovskites have been developed to improve interface stability. These approaches enhance crystallinity, reduce defect-related recombination, and improve mechanical toughness.

A NIR-II Organic Dendrimer with Superb Photothermal Performance Based on Electron-Donor Iteration for Photothermal Immunotherapy.

Organic photothermal materials have attracted extensive attention due to their designable molecular structure, tunable excited-state properties, and excellent biocompatibility, however, the development of near-infrared II (NIR-II) absorbingorganic photothermal materials with high photothermal conversion efficiency (PTCE) and molar extinction coefficient (ɛ) remains challenging. Herein, a novel "electron-donor iteration" strategy is proposed to construct organic photothermal dendrimers (CR-DPA-T, CR-(DPA)2-T and CR-(DPA)3-T) with donor-π-acceptor-π-donor (D-π-A-π-D) features and diradical characteristics. Owing to the enhanced D-A effect and intramolecular motions, their absorption and photothermal capacity increase as the generation grows. Surprisingly, an excellent photothermal performance (ɛ1064 ×PTCE1064) with a superb value of 2.85×104 in the NIR-II region is achieved for CR-(DPA)3-T nanoparticles (CR-(DPA)3-T NPs) compared to most reported counterparts. Besides, CR-(DPA)3-T NPs exhibit superior antitumor efficacy by the synergistic effect of photothermal therapy (PTT)and immunotherapy, efficiently inhibiting the growth of both primary and distant tumors. To the best knowledge, organic photothermal dendrimer is for the first time reported, and a universal donor engineering strategy is offered to develop NIR-II-absorbing organic photothermal materials for photothermal immunotherapy.

A hybrid trans-modal liquid crystal optical vortex generator

This work experimentally validates a large-aperture optical vortex generator using a novel hybrid structure, combining transmission electrode and modal techniques, in what we term the trans-modal technique. The continuous transmission electrode is designed to generate a linear voltage distribution between the contact electrodes, while the electrode stubs distribute the voltage across the active area. A high-resistivity layer of the conducting polymer PEDOT fills the gap between the electrodes, resulting in a completely continuous voltage distribution. A 1-cm aperture device is experimentally demonstrated, but the structure is completely scalable. Theoretical results validate the design, and experimental results demonstrate precise control over the topological charge for both positive and negative values of orbital angular momentum. Remarkably, the conversion efficiency for the first topological charges is almost 100%. The reduction in efficiency of the higher-order modes has been explained theoretically, and it is not caused by design but by the PEDOT characteristics. The fabrication process is straightforward, as the high-resistivity layer may also be inhomogeneous. This work contributes significantly to the field by introducing a novel method for optical vortex generation. The simplicity of the fabrication process, high conversion efficiency, and ability to control the topological charge make this technique a promising avenue for future research and applications.