Conversion Efficiency Research Articles

COOL-LAMPS. VII. Quantifying Strong-lens Scaling Relations with 177 Cluster-scale Strong Gravitational Lenses in DECaLS

Abstract We estimate the Einstein-radius-enclosed total mass for 177 cluster-scale strong gravitational lenses identified by the ChicagO Optically selected Lenses Located At the Margins of Public Surveys (COOL-LAMPS) collaboration with lens redshifts ranging from 0.2 ⪅ z ⪅ 1.0 using the brightest-cluster-galaxy (BCG) redshift and an observable proxy for the Einstein radius. We constrain the Einstein-radius-enclosed luminosity and stellar mass by fitting parametric spectral energy distributions to aperture photometry from the Dark Energy Camera Legacy Survey (DECaLS) in the g-, r-, and z-band Dark Energy Camera filters. We find that the BCG redshift, enclosed total mass, and enclosed luminosity are strongly correlated and well described by a planar relationship in 3D space. We find that the enclosed total mass and stellar mass are correlated with a logarithmic slope of 0.50 0 − 0.031 + 0.029 , and the enclosed total mass and stellar-to-total mass fraction are correlated with a logarithmic slope of − 0.49 5 − 0.033 + 0.032 . In tandem with the small radii within which these slopes are constrained, this may suggest invariance in baryon conversion efficiency and feedback strength as a function of cluster-centric radii in galaxy clusters. Additionally, the correlations described here should have utility in ranking strong-lensing candidates in upcoming imaging surveys—such as Rubin/Legacy Survey of Space and Time—in which an algorithmic treatment of strong lenses will be needed due to the sheer volume of data these surveys will produce.

Seeding Janus Zn-Fe Diatomic Pairs on a Hollow Nanobox for Potent Catalytic Therapy.

Dual atomic nanozymes (DAzymes) are promising for applications in the field of tumor catalytic therapy. Here, integrating with ultrasmall Fe5C2 nanoclusters, asymmetric coordination featuring Janus Zn-Fe dual-atom sites with an O2N2-Fe-Zn-N4 moiety embedded in a carbon vacancy-engineered hollow nanobox (Janus ZnFe DAs-Fe5C2) was elaborately developed. Theoretical calculation revealed that the synergistic effects of Zn centers acting as both adsorption and active sites, oxygen-heteroatom doping, carbon vacancy, and Fe5C2 nanoclusters jointly downshifted the d-band center of Fe 3d orbitals, optimizing the desorption behaviors of intermediates *OH, thereby significantly promoting catalytic activity. Upon 1064 nm laser irradiation, Janus ZnFe DAs-Fe5C2 with superior photothermal conversion efficiency (η = 62.5%) showed thermal-augmented catalytic therapy. Fascinatingly, Janus ZnFe DAs-Fe5C2 with multienzymatic properties can suppress the expression of glutathione peroxidase 4 and accelerate the accumulation of lipid peroxides, through which ferroptosis is triggered. Overall, tannin-involved asymmetric Janus ZnFe DAs-Fe5C2 will inspire more inventions of biodegradable DAzymes for tumor therapy application.

Optimization of Erbium-Doped Fiber to Improve Temperature Stability and Efficiency of ASE Sources

The ASE (Amplified Spontaneous Emission) light source, based on erbium-doped fiber (EDF), is a broadband light source with advantages such as high power, excellent temperature stability, and low coherent light generation. It is widely used in the field of fiber optic sensing. However, traditional ASE sources suffer from temperature sensitivity and low efficiency, which can compromise the accuracy and stability of the output light’s average wavelength. This study focuses on optimizing the erbium-doped fiber (EDF) to improve the temperature stability and efficiency of the ASE light source. Through simulations, we found that the appropriate doping concentration and length of the EDF are key factors in enhancing the stability and efficiency of the ASE source. Inorganic metal chloride vapor-phase doping combined with an improved chemical vapor deposition process was used to fabricate the erbium-doped fiber, ensuring low background loss, minimal OH− absorption, and uniform distribution of the erbium ions in the core of the fiber. The optimized EDFs were integrated into the ASE source, achieving a power conversion efficiency of 53.6% and a temperature stability of 0.118 ppm/°C within the temperature range of −50 °C to 70 °C. This study offers a practical approach for improving the performance of ASE light sources and advancing the development of high-precision fiber optic sensing technologies.

Optimized Interface Engineering Enhances Carrier and Phonon Scattering for Superior Thermoelectric Performance in Yb-Filled Skutterudites.

Thermoelectric (TE) performance in materials is often constrained by the strong coupling between carrier and phonon transport, necessitating trade-offs between electrical and thermal properties that limit improvements in the figure of merit (zT). Herein, a novel strategy is proposed to achieve simultaneous energy filtering and enhanced phonon scattering, effectively optimizing the TE properties of CoSb3-based skutterudites. By introducing Cu2Te nanoprecipitates into the Yb0.3Co4Sb12 matrix, interfacial barriers are formed, which selectively filter low-energy charge carriers, significantly improving the Seebeck coefficient while maintaining high carrier mobility. As a consequence, a substantial enhancement of the power factor occurs. Furthermore, the multiscale precipitates inhibit grain boundary migration, leading to grain refinement, and effectively scatter phonons, consequently decreasing the lattice thermal conductivity. These synergistic improvements in electronic and phonon transport yield a peak zT of ∼1.47 at 823 K for the Yb0.3Co4Sb12 + 0.5%Cu2Te sample. Furthermore, a fabricated 7-pair TE module attains a maximum conversion efficiency of ∼6.1% under a temperature difference of 400 K. This work introduces a straightforward and effective approach for designing high-performance TE material systems through the collaborative tuning of electrical and thermal properties.

Temperature and pump modulation investigation of an Er:Yb co-doped fiber laser with optimized SWaP

This paper presents the results of experimental and theoretical studies of the influence of temperature and pump modulation on an erbium:ytterbium co-doped fiber laser in context for an optimized size, weight, and power (SWaP) integration. The fiber laser setup including the active fiber and pump diode lasers are heated up or cooled down for ranging temperatures from 0°C till 60°C and in parallel the output power is measured. Experimental results show that the slope efficiency of the fiber laser is constant over the measured temperature range. A slight decrease of the electro-optical conversion efficiency with increasing temperature is observed. Furthermore, the erbium:ytterbium co-doped fiber laser is pump modulated and the rise time as well as the frequency response is measured. The experimental results of the pump modulated fiber laser are compared with a time resolved simulation. The investigation shows that a minimum rise time of 36.6 µs and a maximum modulation depth of 9.4 dB can be reached. Moreover, the modulated laser amplitude is measured. The laser amplitude experiences a 3 dB attenuation at a modulation frequency of 20 kHz that agrees with the simulation results taking partly coupled ytterbium ions into account.

Recent advances in non‐noble metal‐based electrocatalysts for hybrid water electrolysis systems

AbstractThe electrocatalytic water‐splitting process is widely acknowledged as the most sustainable and environmentally friendly technology for hydrogen (H2) production. However, its energy efficiency is significantly constrained by the kinetically slow oxygen evolution reaction (OER) at the anode, which accounts for about 90% of the electrical energy consumption in the water‐splitting process. A new strategy is urgently needed to reduce its energy consumption. In recent years, electrochemical oxidation of small molecules has been considered for replacement of OER for efficient H2 production, due to its benign operational conditions, low theoretical thermodynamic potential, high conversion efficiency and selectivity, and environmental sustainability. Hybrid electrolysis systems, by integrating cathodic hydrogen evolution reaction with anodic oxidation of small molecules, have been introduced, which can generate high‐purity H2 and produce value‐added products or pollutant degradation. In this review, we highlight the recent advancements and significant milestones achieved in hybrid water electrolysis systems. The focus is on non‐noble metal electrocatalysts, reaction mechanisms, and the construction of electrolyzers. Additionally, we present the prevailing challenges and future perspectives pertinent to the evolution of this burgeoning technology.

Solvent-Mediated Growth of a Hierarchical Zero-Dimensional Architecture for Efficient CsPbI3 Quantum Dot Solar Cells.

Perovskite quantum dots (QDs) are promising optoelectronic materials. The large surface area provides an opportunity for ligand engineering to protect the QDs, while also impeding the charge transport in the QD array. Here, the solvent-mediated growth of a hierarchical zero-dimensional (HZD) architecture between CsPbI3 QDs is reported. The HZD architecture is grown on the CsPbI3 QD film through a feasible method rather than introducing intricate molecules into the CsPbI3 QD solution. Acetonitrile solvent with high polarity strips lead iodide from the QD surface, and then the lead iodide reacts with the phenethylamine iodide to form HZD architecture. The HZD architecture acts as a "charge bridge" to enhance the coupling between CsPbI3 QDs, resulting in improved photoelectric properties. As a result, the optimized device achieves a high-power conversion efficiency of 15.4%, remarkably higher than the 14% of the control device. This work demonstrates the significance of surface chemistry for perovskite QDs and provides a feasible strategy for realizing high-performance perovskite QDs-based optoelectronic devices.

Over 19.2% Efficiency of Layer‐By‐Layer Organic Photovoltaics by Ameliorating Exciton Dissociation and Charge Transport

AbstractLayer‐by‐layer (LbL) organic photovoltaics (OPVs) are fabricated with polymer PM1 as donor and small molecule L8‐BO as acceptor by employing sequential spin‐coating technology. The small molecule BTP‐eC9 and polymer PTAA are deliberately selected for individually incorporating into PM1 layer and L8‐BO layer, resulting in the power conversion efficiency (PCE) increased from 18.22% to 19.23%. The improvement of performance is attributed to the synergistically increased short circuit current density (JSC) of 27.78 mA cm−2 and fill factor (FF) of 78.23%. The introduction of BTP‐eC9 into PM1 layer can promote the photogenerated exciton dissociation, especially for the excitons near the anode. Meanwhile, molecular crystallinity of PM1 is also enhanced by incorporating appropriate BTP‐eC9 into PM1 layer. The incorporation of PTAA into L8‐BO layer can provide hole transport channels to effectively improve the transport of holes generated by the self‐dissociation of L8‐BO, resulting in the enhanced FFs from 77.40% to 78.23%. The synergistic effects of BTP‐eC9 and PTAA incorporation in donor and acceptor layers result in a 19.23% PCE of the optimized LbL‐OPVs. This work demonstrates that there is great room to hierarchically optimize donor and acceptor layers for achieving highly efficient LbL‐OPVs.

Micro-Size Layers Evaluation of CIGSe Solar Cells on Flexible Substrates by Two-Segment Process Improved for Overall Efficiencies

This paper details the enhancement of the optoelectronic properties of Cu-(In, Ga)-Se2 (CIGSe) solar cells through a two-segment process in the ultraviolet (UV)–visible spectral range. These include fine-tuning the DC sputtering power of the absorber layer (ranging from 20 to 40 W at segment I) and thoroughly checking the trace micro-chemistry composition of the absorber layer (CdS, ZnO/CdS, ZnMgO/CdS, and ZnMgO at segment II). After segment I of treatment, the optimal 30 W CIGSe absorber layer (i.e., with a 0.95 CGI ratio) can be obtained, it can be seen that the Cu-rich film exhibits the ability to significantly promote grain growth and can effectively reduce its trap state density. After the segment II process aimed at replacing toxic CdS, the optimal metal alloy (Zn0.9Mg0.1O) composition (buffer layer) achieved the highest conversion efficiency (η) of 8.70%, also emphasizing its role in environmental protection. Especially within the tunable bandgap range (2.48–3.62 eV), the developed overall internal and external quantum efficiency (IQE/EQE) is significantly improved by 13.15% at shorter wavelengths. A photovoltaic (PV) module designed with nine optimal CIGSe cells demonstrated commendable stability. Variation remained within ±5% throughout the 60-day experiment. The PV modules in this study represent a breakthrough benchmark toward a significant advance in the scientific understanding of renewable energy. Furthermore, this research clearly promotes the practical application of PV modules, harmonizes with sustainable goals, and actively contributes to the creation of eco-friendly communities.

In situ generation of Copper sulfide within Poly(lactic-co-glycolic acid): A strategy for Safer photothermal therapy in Triple-Negative breast cancer.

Copper sulfide nanoparticles (CuS NPs) have garnered significant attention in photothermal therapy (PTT) owing to their facile synthesis, biodegradability, stability, and excellent photothermal conversion efficiency. Nonetheless, their potential toxic effects have restricted their application. This research focuses on the encapsulation of CuS NPs with the biocompatible polymer poly(lactic-co-glycolic acid) (PLGA) to enhance their biocompatibility, thereby improving the efficacy and safety of PTT in the treatment of triple-negative breast cancer (TNBC). Three distinct methods, namely aqueous phase loading method, oil phase loading method, and "in situ reduction" method were employed to synthesize PLGA-coated CuS (CuS@PLGA) NPs to optimize the encapsulation rate of CuS. Among these, the CuS@PLGA NPs fabricated via the "in situ reduction" method demonstrated the highest encapsulation efficiency for CuS, achieving a rate of (90.4 ± 3.3)%. The resulting CuS@PLGA NPs exhibited high stability, excellent photothermal effect, and good tumor-targeting ability. Moreover, CuS@PLGA NPs demonstrated enhanced anti-tumor efficacy and biocompatibility compared to CuS NPs in both in vitro and in vivo experiments. Consequently, this study offers an effective and safety strategy for PTT treatment of TNBC.

A Review on Recent Advances in Flexible Perovskite Solar Cells

Flexible perovskite solar cells (FPSCs), featured with lightweight, high efficiency, and low cost, have attracted much attention anticipating in applications on wearable electronics, near‐space vehicles, and internet of things. High efficiency and mechanical stability are two main factors in the study of FPSCs toward practical applications. In recent few years, many breakthroughs in materials modification and device innovation make the power conversion efficiency of FPSCs reach over 25%. A comprehensive review thus is conducted to elucidate the critical issues including flexible substrates, transparent electrodes, charge transport layers, perovskite films, and modifications for mechanical enhancement of FPSCs, which is expected to promote the future development of FPSCs.

Enhanced Efficiency and Stability of Tin Halide Perovskite Solar Cells Through MOF Integration.

Tin halide perovskites are promising candidates for lead-free perovskite solar cells due to their ideal bandgap and high charge-carrier mobility. However, poor crystal quality and rapid degradation in ambient conditions severely limit their stability and practical applications. This study demonstrates that incorporating UiO-66, a zirconium-based MOF, significantly enhances the performance and stability of tin halide perovskite solar cells (TPSCs). The unique porous structure and abundant carboxylate groups of UiO-66 improve the crystallinity and film quality of FASnI₃, reduce defect density, and prolong charge carrier lifetimes. Consequently, the power conversion efficiency (PCE) of UiO-66-integrated TPSCs increases from 11.43% to 12.64%, and the devices maintain over 90% of their initial PCE after 100 days in a nitrogen glovebox. These findings highlight the potential of UiO-66 in addressing the efficiency and stability challenges of tin halide perovskites.

Reducing Nonradiative Recombination in Halide Perovskites through Appropriate Band Gaps and Heavy Atomic Masses.

Halide perovskite optoelectronic devices achieve high energy conversion efficiencies. However, their efficiency decreases significantly with an increase in temperature. This decline is likely caused by changes in nonradiative recombination and electron-phonon coupling, which remain underexplored. When the perovskite lattice temperature increases, anharmonicity induces energy level fluctuation and band gap narrowing by modulating electron-phonon interactions. As lattice vibrations intensify, high-frequency phonons progressively dominate the carrier dynamic processes in halide perovskites, thereby strengthening the coupling between the electronic subsystem and high-frequency phonons. The increased overlap of electron wave functions strengthens non-adiabatic coupling, thereby accelerating the nonradiative recombination process. On the basis of these findings, we propose the introduction of appropriate band gap materials and heavy atoms at the B-site and X-site to modulate electron-phonon coupling, thereby mitigating nonradiative recombination and enhancing halide perovskite solar cell performance.

Thermal Annealing Effect on Properties of Nickel Oxide (NiO) Thin Films for Photovoltaic Applications

In this study, the impact of annealing temperature (TA) from room temperature (RT) to 400 °C on the structural, optical and electrical properties of NiO thin films deposited using sol‐ gel spin coating technique on glass substrate is presented. A theoretical approach is also employed to calculate the open circuit voltage (VOC) from the energy band gap (Eg) value, fill factor (FF), short circuit current (ISC), and power conversion efficiency (PCE) of the material for solar cell applications. Crystallinity improvement is observed upon annealing the NiO thin films and the average size of crystallites varies from 28 to 34 nm with a maximum value observed for 300 °C annealed film. The SEM micrographs confirm the nano form of NiO nanoparticles, with particles that are between 73 and 100 nm in size. All the films are semitransparent with transmittance >55% and the thin film annealed at 300 °C exhibited 88% transmittance in the visible region, making it a promising option as a transparent conducting oxide (TCO) in photovoltaic applications. The I–V curves display a non‐linear behaviour for all annealing temperatures. The conductivity increases with an increase in TA and the film annealed at 300 °C shows the highest conductivity.

Enhanced Interlayer Interactions in Tin Halide Perovskite Solar Cells with a Fluorinated Fullerene Derivative.

Lead-free tin halide perovskite solar cells (TPSCs) have recently made significant progress in power conversion efficiency (PCE). However, the presence of mismatched energy levels and weak interlayer interactions between the electron transport materials (ETMs) and tin perovskites has limited the achievable PCE. Here, a new fluorinated fullerene derivative, C60-FTPA (F12), was designed and synthesized to construct a binary ETM with C60-ETPA (F6) reported in our group, resulting in a reduction in defects and improved molecular structure ordering. Furthermore, the binary ETM exhibited a stronger interaction with the tin perovskite and delivered a PCE up to 11.93%.

Solvent-dripping modulated 3D/2D heterostructures for high-performance perovskite solar cells

The controlled growth of two-dimensional (2D) perovskite atop three-dimensional (3D) perovskite films reduces interfacial recombination and impedes ion migration, thus improving the performance and stability of perovskite solar cells (PSCs). Unfortunately, the random orientation of the spontaneously formed 2D phase atop the pre-deposited 3D perovskite film can deteriorate charge extraction owing to energetic disorder, limiting the maximum attainable efficiency and long-term stability of the PSCs. Here, we introduce a meta-amidinopyridine ligand and the solvent post-dripping step to generate a highly ordered 2D perovskite phase on the surface of a 3D perovskite film. The reconstructed 2D/3D perovskite interface exhibits reduced energetic disorder and yields cells with improved performance compared with control 2D/3D samples. PSCs fabricated with the meta-amidinopyridine-induced phase-pure 2D perovskite passivation show a maximum power conversion efficiency of 26.05% (a certified value of 25.44%). Under damp heat and outdoor tests, the encapsulated PSCs maintain 82% and 75% of their initial PCE after 1000 h and 840 h, respectively, demonstrating improved practical durability.

Interfacial Work Function Modulation of Wide Bandgap Perovskite Solar Cell for Efficient Perovskite/CIGS Tandem Solar Cell.

Wide-bandgap perovskite solar cells (PVSCs), a promising top-cell candidate for high-performance tandem solar cells, often suffer from larger open-circuit voltage (VOC) deficits as the bandgap increases. Surface passivation is a common strategy to mitigate these VOC deficits. However, understanding the mechanisms underlying the differences in passivation effects among various types of molecules remains limited, which is crucial for developing universal interface passivation strategies and guiding the design of passivation molecules. This study compares the passivation effects of phenethylammonium iodide (PEAI) and piperazine iodine (PI) on VOC in wide-bandgap PVSCs with a 1.66eV bandgap. Results show that PI significantly enhances VOC, whereas PEAI does not. This improvement is attributed to increased built-in voltage (Vbi) in PI-treated PVSCs, stemming from a lower work function, which enhances carrier selectivity at the contact interfaces. The champion power conversion efficiency of the PVSCs is 21.47%, with a VOC of 1.23V and a VOC loss of 0.43V. The strategy is also effective for PVSCs with bandgaps of 1.56 and 1.81eV. By layering semi-transparent perovskite top cells onto copper indium gallium selenide (CIGS) bottom cells, a PCE of 26.36% is achieved in perovskite/CIGS 4-terminal tandem solar cells.

All Inorganic CsPbBr3 Perovskite Solar Cells Based on Preferential Crystallization of Buried Interface Regulated by CsCl

Compared to organic–inorganic hybrid perovskite solar cells (PSCs), all inorganic CsPbBr3 perovskite solar cells have higher stability but lower efficiency. Owing to the low solid solubility of CsBr in methyl alcohol, an incomplete first-step reaction with PbBr2 reaction takes place at room temperature. As a result, a large amount of CsPb2Br5 is generated in the final CsPbBr3 film, which deteriorates the performance of CsPbBr3 PSCs. Along these lines, in this work, CsCl was added to increase the reaction between CsBr and PbBr2 in the first step and high-quality CsPbBr3 films were prepared without CsPb2Br5. Our analysis demonstrated that at the optimal CsCl concentration of 6% in CsBr solution, the CsPbBr3 perovskite solar cells exhibited a power conversion efficiency of 7.33%. The best device retained 98.57% of the power conversion efficiency (PCE) after storing it for 30 days under ambient air condition.

Nonlinearity Manipulation for Highly Efficient Modal Phase‐matched Second Harmonic Generation on Thin‐Film Lithium Niobate

AbstractWhile modal phase matching (MPM) shows great potential for adaptable engineering in quadratic nonlinear optical processes, poor mode overlap in traditional MPM persists as a key challenge. In this paper, a flexible domain engineering method are proposed and demonstrated for second‐harmonic generation (SHG) on thin‐film lithium niobate (TFLN). By meticulously tuning the electric field intensity applied to the poling electrodes with an Al2O3 layer, the depth of domain inversion layer in TFLN can be controlled flexibly and locally, leading to the manipulation of nonlinearity, which effectively increases the mode overlap. SHG in the dual‐layer TFLN ridge waveguides has been experimentally realized with a normalized conversion efficiency of 8300% W−1 cm−2. The flexible and fabrication‐friendly approach provides a versatile method for diverse MPM scenarios, and presents considerable potential for efficient quadratic nonlinear processes.

Nonlinear Nitrogen‐Doped Carbon‐Based All‐Optical Switch and Wavelength Converter in Mid‐Infrared Region

AbstractExploring all‐optical devices built upon new nanomaterials and moving toward all optical signal processing has been attracted ever‐growing interest. Nitrogen‐doped carbon shows tremendous application potential in nonlinear optics due to its excellent and stable optoelectronic characteristics. Due to the reduction in scattering intensity as increasing optical wavelength, the midinfrared 2 µm band is less affected by atmospheric scattering. This study presents an experimental demonstration of a 2 µm optical Kerr switch on a microfiber, designed using nonlinear nitrogen‐doped carbon nanospheres (NCN), and combined with a highly nonlinear fiber (HNLF) to achieve cascaded four‐wave mixing (FWM) phenomena. Experimental results show that the Kerr switch exhibits an extinction ratio of approximately 12.5 dB under appropriate pump light application, indicating effective signal light control. Moreover, the maximum conversion efficiency of the first‐order cascaded FWM reaches −20.08 dB, and the second‐order efficiency reaches −39.3 dB, with a maximum wavelength spacing of 18 nm. This represents the first investigation of optical Kerr switching and cascaded FWM in the 2 µm wavelength range. This study provides new insights and approaches for developing optical signal processing technology and lays the foundation for future high‐performance photonic devices in this wavelength range.