High Conversion Efficiency Research Articles

Characterization of Ultrathin Layers in Perovskite/TOPCon Tandem Cells With Photoelectron Spectroscopy Utilizing Advanced Data Evaluation Methods

Next generation solar cells like tunnel oxide passivated contacts (TOPCon) or perovskite/TOPCon tandem solar cells require efficient interface passivation by ultrathin organic or inorganic layers to uncover their true efficiency potential. Especially the microstructure and the Si suboxide content of the tunnel oxide in poly-Si(Ox)/SiO2/c-Si TOPCon stacks have been shown to have a tremendous influence on macroscopic device properties. Similarly, perovskite/ITO interface modification by a self-assembled monolayer (SAM) molecule is necessary to achieve high power conversion efficiencies of the perovskite sub cell. However, the characterization of such thin film structures and the interfacial composition is challenging. In this contribution, we present characterization results of ultrathin passivation layers using angle-resolved X-ray photoelectron spectroscopy (XPS) and advanced data evaluation routines, including maximum entropy methods and analyses of inelastically-scattered electron background data. In particular, the interfaces in the stacks (1) partially oxidized a-Si/SiO2/c-Si and (2) 2PACz/ITO after different thermal treatment were investigated. It could be shown that already a ~5 nm thin SiNx layer prevents unwanted oxidation from ambient during cooldown of TOPCon-like stacks and that annealing above 100 °C can convert a 2PACz multilayer to a 2PACz monolayer on an ITO substrate.

Equally high efficiencies of organic solar cells processed from different solvents reveal key factors for morphology control

AbstractThe power conversion efficiency of organic solar cells (OSCs) is exceeding 20%, an advance in which morphology optimization has played a significant role. It is generally accepted that the processing solvent (or solvent mixture) can help optimize morphology, impacting the OSC efficiency. Here we develop OSCs that show strong tolerance to a range of processing solvents, with all devices delivering high power conversion efficiencies around 19%. By investigating the solution states, the film formation dynamics and the characteristics of the processed films both experimentally and computationally, we identify the key factors that control morphology, that is, the interactions between the side chains of the acceptor materials and the solvent as well as the interactions between the donor and acceptor materials. Our work provides new understanding on the long-standing question of morphology control and effective guides to design OSC materials towards practical applications, where green solvents are required for large-scale processing.

Chloride Engineering for Boosting Perovskite Photovoltaics: Impact on Precursor Coordination, Crystallization, and Film Quality.

Perovskite solar cells (PSCs) have seen rapid advancements over the past decade, driven by their exceptional optoelectronic properties and high power conversion efficiencies. Cl-based additives strategy has significantly contributed to these advancements by enhancing crystallinity, improving preferred orientation, and optimizing the surface morphology of perovskite films. This review provides a comprehensive summary of recent advancements and insights into the critical role of Cl-based additives in perovskite photovoltaics, focusing on the mechanisms behind Cl incorporation and its effects on film and device performance. First, the impact of Cl on precursor solution coordination and colloidal characteristics is discussed. Then, how Cl-based additives influence the phase transitions of perovskites, including methylammonium lead iodide (MAPbI3), formamidinium lead iodide (FAPbI3), and 2D perovskites is examined. Furthermore, the impact of Cl-based interfacial treatments on perovskite film quality is explored. Based on these insights, the overall impact of Cl treatments is also reviewed on the properties of perovskite films. Finally, a brief overview of the remaining challenges and future perspectives are provided to guide ongoing research efforts toward optimizing Cl additive engineering for high-performance PSCs.

Studying the effects of temperature on InGaP/InGaAs/Ge triple junction solar cells using PyAMS Software

Multi-junction solar cells, particularly those utilizing III–V semiconductor materials, offer high conversion efficiency by employing multiple P-N junctions with different band gap energies to capture specific wavelengths of sunlight. Among these, the triple-junction photovoltaic cell, comprising Indium Gallium Phosphide (InGaP), Indium Gallium Arsenide (InGaAs), and Germanium (Ge) subcells, stands out for its efficiency. However, temperature variations significantly impact the performance of these subcells, necessitating a comprehensive understanding of their thermal behavior. In this study, we employ PyAMS (Python for Analog and Mixed Signals) software to model and simulate the behavior of InGaP/InGaAs/Ge sub cells under varying temperature conditions. Through comparison with experimental data, we validate our model and analyze key performance parameters, including short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), and overall efficiency (η). Our findings reveal minimal changes in short circuit current density with temperature, while the open circuit voltage exhibits a substantial decrease beyond 60°C when exposed to concentrated illumination of 10 Suns, significantly impacting fill factor and efficiency. By elucidating the thermal behavior of three-junction solar cells, our study contributes valuable insights for designing and implementing cooling systems, thereby enhancing the performance and reliability of photovoltaic systems in practical applications.

Experimental study of a backward bent duct buoy wave energy converter: Effects of the air chamber and center of gravity height

The backward-bent duct buoy (BBDB) wave energy converter (WEC) is a floating oscillating water column (OWC) device with high conversion efficiency and low mooring requirements. This study experimentally investigates the effects of air chamber volume, chamber top shape, and center of gravity height on the wave energy capture performance of BBDB WEC. The results indicate that increasing the air chamber's volume enhances conversion performance. When the air chamber volume is increased from 0.0162 m³ to 0.0233 m³, the maximum capture width ratio (CWR) increases by 0.14 and 0.13 at wave amplitudes of 0.015 m and 0.025 m, respectively. An oblique cut prism chamber improves performance under low wave periods. When using a chamber with an inclined top, conversion performance exceeds that of a rectangular chamber, with the maximum CWR increasing from 1.09 to 1.40 at a wave height of 0.015 m and from 0.82 to 1.01 at a wave height of 0.025 m. Additionally, changes in center of gravity height primarily affect conversion efficiency during the pitch resonance period. These findings contribute to the structural optimization and performance enhancement of BBDB WECs.

Quasi-solid-state monolithic DSSCs with optimized spacer layers and composite electrolytes for better efficiency and stability

In this study, high-performance quasi-solid-state monolithic dye-sensitized solar cells (QS-M-DSSCs) were designed using an optimized spacer layer architecture to enhance electrolyte transport and improve cell performance. Spacer layers, made from a combination of zirconium oxide (ZrO2) and titanium dioxide (TiO2), were precisely tuned to reduce mass-transport limitations. A 5.2 μm thick ZrO2/TiO2 layer provided good light reflectance and incident photon-to-current conversion efficiency compared to double layers of either material alone. Electrochemical impedance spectroscopy analysis of the m-DSSCs revealed that this architecture (photoelectrode TiO2 layer/ZrO2/TiO2 spacer layer/counter electrode catalyst layer) significantly increased recombination resistance, leading to an improvement in open-circuit voltage. As a result, acetonitrile iodide liquid-DSSCs using N719 dye achieved a high power conversion efficiency (PCE) of 8.45 %, surpassing cells with alternative spacer designs. For fully printable QS-M-DSSCs, printable gel electrolytes (PGEs) composed of polyethylene oxide and polymethyl methacrylate in 3-methoxypropionitrile (MPN) were employed. A 5 wt% PEO/PMMA composition demonstrated fast and efficient penetration of the PGEs through spacer layers. Moreover, incorporation of 4 wt% TiO2 nanoparticles into PGEs further enhanced their electrochemical properties, achieving a PCE (7.31 %) higher than cells with liquid electrolytes (6.72 %). QS-M-DSSCs demonstrated greater stability than liquid-state DSSCs.

Impact of Self-Assembled Monolayer Structural Design on Perovskite Phase Regulation, Hole-Selective Contact, and Energy Loss in Inverted Perovskite Solar Cells

Recent studies have shown that self-assembled molecule (SAM)-based hole-selective contacts (HSCs) offer a promising solution to the challenges faced by perovskite solar cells (PVSCs), including minimal material consumption, scalable production, high interface stability, and the use of environmentally friendly solvents. In this study, the efficacy of two designs of SAMs (Cz and PA) as HSCs in inverted PVSCs was investigated by comparing them with the conventional MeO-2PACz (MeO) SAM. Surface analyses showed that the surface of PA is smoother than that of Cz, which helps to reduce interfacial defects. Subsequent perovskite deposition exhibited a reduced formation of the PbI2 phase, incidiating that its phase modulation ability is superior to that of MeO. Further analyses demonstrate the superior charge extraction ability of PA as a result of reduced interfacial defects and non-radiative recombination at the HSC/perovskite interface. By further coupling with phenethylammonium iodide (PEAI) surface passivation, both interfaces of the perovskite film were optimized and the inverted ((FAPbI3)0.85(MAPbBr3)0.15)0.95(CsPbI3)0.05 (bandgap = 1.62eV) PVSC achieves a high power conversion efficiency (PCE) of 23.3% and a very high open-circuit voltage of 1.227V due to the largely reduced energy loss. In addition, the PA PVSC exhibits enhanced long-term thermal stability at 85°C in a nitrogen atmosphere.

Evaluating the electronic and structural basis of carbon selenide-based quantum dots as photovoltaic design materials: A DFT and ML analysis

We present a new study on the design, discovery and space generation of carbon selenide based photovoltaic (PV) materials. By extending acceptors and leveraging density functional theory (DFT) and machine learning (ML) analysis, we discover new QDs with remarkable PV properties. We employ various ML models, to correlate the exciton binding energy (Eb) of 938 relevant compounds from literature with their molecular descriptors of structural features that influence their performance. Our study demonstrates the potential of ML approaches in streamlining the design and discovery of high-efficiency PV materials. Also the RDKit computed molecular descriptors correlates with PV parameters revealed maximum absorption (λmax) ranges of 509–531 nm, light harvesting efficiency (LHE) above 92 %, Open Circuit Voltage (Voc) of 0.22–0.45 V, and short Circuit (Jsc) currents of 37.92–42.75 mA/cm2. Their Predicted Power Conversion Efficiencies (PCE) using the Scharber method reaches upto 09–13 %. This study can pave the way for molecular descriptor-based design of new PV materials, promising a paradigm shift in the development of high-efficiency solar energy conversion technologies.

Efficient Cryogenic Nonlinear Conversion Processes in Periodically‐Poled Thin‐Film Lithium Niobate Waveguides

AbstractPeriodically poled thin‐film lithium niobate (TFLN) waveguides, which enable efficient quadratic nonlinear processes, serve as crucial foundation for classical and quantum signal processing. To expand their application scope, the first investigation of nonlinear conversion processes in periodically poled TFLN waveguides at cryogenic conditions (7 K) is provided. Through systematic experimental characterization, it is found that the periodically poled TFLN waveguide retains its high conversion efficiency at both cryogenic and room temperatures for both classical second‐harmonic generation and quantum photon‐pair generation processes. Particularly, the photon‐pair source at cryogenic conditions shows high brightness (≈8 MHz µW−1) and broad bandwidth (>100 THz). These results demonstrate the significant potential of TFLN wavelength conversion devices for cryogenic applications and foster future scalable quantum photonic systems.

A Survey Paper on Plastic Solar Cell Technology

The demand of energy is increasing day by day so non-conventional source of energy has to be used. Sun is the nonconventional source of energy. Conventional solar panels convert solar energy into electrical energy. A plastic solar cell is the type of photovoltaic that makes use of organic electronics dealing with conductive organic polymers or small molecules for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Polymers Provide the Advantage of Solution Processing at Room Temperature, which is Less Expensive and Enables One to Use Plastics. Therefore, If Silicon Is Replaced with Polymer Nanowires, The Solar Cell Would Be Much Lighter and Ultimately Less Costly. These Solar Cells are Thin, Several Microns in Diameter, and Scavenge All the Rays from the Sun's Radiation. Plastic Solar Cell Technology is Based on Conjugated Polymers and Molecules. Polymer Solar Cells have Generated Considerable Interest Since it Provides Environmentally Friendly, Flexible, Lightweight, Low Cost, Possibility of High-Efficiency Solar Cells in the Last Couple of Decades. Plastic Solar Cells are More Efficient and Viable in Usage. This dissertation focuses on the development and optimization of plastic solar cell technology, in particular this potential towards flexible, lightweight, and cost-effective alternative sources to traditional silicon-based solar cells. The focus of the present research work is to find optimum organic materials for higher efficiency and stability in plastic solar cells, varying from conjugated polymers to small organic molecules. Some of the main goals are improving the charge transport mechanisms and optimizing the architecture of devices through state-of-the-art techniques of fabrication, like roll-to-roll printing and layer-by-layer deposition. The other key aspect is that the project assesses the environmental aspects and lifecycle of plastic solar cells to ensure an environmentally friendly production process. Huge preliminary results were achieved at high power conversion efficiencies and durability has been greatly improved, targeting very wide spread application from portable electronics up to building-integrated photovoltaics. Therefore, the discovery of plastic solar cells might be a major step for applicable solutions in renewable energy and towards overcoming the world's increasing energy challenges.

Dual-interface passivation to improve the efficiency and stability of inverted flexible perovskite solar cells by in-situ constructing 2D/3D/2D perovskite double heterojunctions

Perovskite solar cells (PSCs) have demonstrated considerable potential as a promising photovoltaic technology. Nevertheless, the continued advancement is impeded by the presence of interfacial defects, which give rise to nonradiative recombination and ion migration. In this work, we demonstrate a simple and effective method to in-situ construct 2D/3D/2D perovskite double heterojunctions for effective passivation of defects and mitigation of ion migration in 3D perovskites. As a result, the inverted double-heterojunction PSCs exhibited a high power conversion efficiency (PCE) of 24.08 % with a low VOC loss of 0.37 V due to the minimal nonradiative recombination by dual-interface passivation. The stability of double-heterojunction devices has been significantly improved, maintaining 92 % of the initial value after 3000 h of storage under indoor light in a N2 atmosphere. Especially, the 2D/3D/2D perovskite double heterojunctions are applicable to flexible PSCs (FPSCs) to enhance both PCE and mechanical stability by effective residual stress release. Consequently, the FPSCs demonstrated a PCE of 21.58 % while retaining 86 % of the initial PCE even after undergoing a multi-cycle bending test for 10,000 cycles.

Minimizing vacancy defects with Eu passivation strategy to enable highly efficient perovskite photovoltaics

The intrinsic ionic nature of metal halide perovskites facilitates the formation of abundant defects at grain boundaries (GBs) and surfaces, consequently diminishing the stability and photovoltaic performance of perovskite solar cells (PSCs). Due to the low formation energies and instability of Pb-I bonds, iodine (I) and lead (Pb) vacancies are prevalent high-density point defects. In this study, we explore the use of europium (Eu) as a novel passivator to concurrently address I and Pb vacancies through first-principles calculations. Our results demonstrate that Eu significantly lowers the defect formation energies and adjusts the bandgap, enlarged by vacancy defects, to align with the ideal Shockley-Queisser limit, indicating a strong potential for achieving high power conversion efficiency (PCE). Furthermore, Eu passivation markedly increases the activation energy barriers for ion migration, resulting in substantially reduced migration rates. This suggests a minimal likelihood of I and Pb ion migration on defected surfaces, underscoring Eu’s potential to mitigate hysteresis effects and enhance stability. This work advances our understanding of the passivation effects of rare earth elements and establishes a foundation for designing highly effective passivation strategies to achieve stable and efficient PSCs.

Isolated High-Gain DC-DC Converter with Nanocrystalline-Core Transformer: Achieving 1:16 Voltage Boost for Renewable Energy Applications

This paper presents an isolated DC-DC converter with high voltage gain that features an advanced inter-built nanocrystalline-core medium-frequency transformer (NC-MFT). The isolated DC-DC converter with an NC-MFT is specifically designed for applications such as interconnect photovoltaic (PV) systems, DC microgrids, DC loads, and DC buses, where voltage gain is one of the essential issues to consider. The NC-MFT inside the DC-DC converter is designed with a new approach that not only provides isolation but also contributes to achieving high efficiency and a higher step-up ratio. The high efficiency of the converters contributes to the integration of PV systems into DC microgrids. The converter yields a high voltage conversion ratio of 16.17. The experimental results obtained at 41.8 V/676 V and 275 W for the prototype revealed high efficiency (95.63% at full load). The experimental results validate the theoretical analysis and simulation, confirming that the converter achieves the main objective of high voltage conversion and high efficiency. These results will contribute to the interest in the use of this type of energy and its impact on the reduction in CO2 emissions.

Low lattice thermal conductivity induced by antibonding sp-hybridization in Sb2Sn2Te6 monolayer with high thermoelectric performance: A First-principles calculation

Utilizing first-principles calculations and Boltzmann transport theory, the crystal structure, thermal and electronic transport, and thermoelectric (TE) properties of the Sb2Sn2Te6 monolayer are evaluated in the current work. The Sb2Sn2Te6 monolayer is an indirect band gap semiconductor with a band gap of 0.81 eV using the Heyd-Scuseria-Ernzerhof (HSE06) functional in combination with the spin-orbital coupling (SOC) effect. The antibonding states formed by the hybridization of Sb s orbital with Te p orbital near the Fermi level weaken the bonding strength of the Sb-Te bond, leading to significant anharmonicity and low group velocity. Thus, a low lattice thermal conductivity of 2.77 W/m K is achieved for the Sb2Sn2Te6 monolayer at 300 K. The band convergence and multivalley characteristics in the electronic band structure give birth to the enhancements of Seebeck coefficients and carrier mobilities, resulting in a substantial power factor of 76.69 μW/mK2 at 300 K under the carrier concentration of 3.20×1020 cm−3. An optimal figure of merit (ZT) of 2.37 at 900 K for the Sb2Sn2Te6 monolayer is obtained under the carrier concentration of 2.42×1020 cm−3. The present work not only provides fundamental insights into the correlation between the antibonding state, chemical bond and lattice thermal conductivity in Sb2Sn2Te6 monolayer, but also elaborates on the promising prospect of the Sb2Sn2Te6 monolayer in the TE application with high conversion efficiency.

Biomass-based photothermal fabrics and superhydrophobic aerogel for self-floating solar evaporators with high energy efficiency in fresh water production from seawater

In the context of global water scarcity, solar-powered seawater desalination represents a highly promising approach to addressing the freshwater crisis, offering a green and sustainable solution. However, conventional solar evaporators (SEs) often have issues such as salt deposition and heat loss by conduction, which result in decreased evaporation rates energy efficiency. Moreover, they often require the use of challenging-to-degrade polymer materials as the insulation layers and buoyancy support. In this study, we fabricated a novel energy-efficient SE capable of self-standing/self-floating with biomass materials for biodegradability and sustainability. The photothermal layer of the SE was made with waste cotton cloth modified with CuS for high hydrophilicity and photothermal conversion efficiency, with hierarchical pores for rapid water delivery to the evaporation surface. The supporting base of the SE was made biomass-based superhydrophobic aerogel to provide effective thermal insulation and self-floating ability. The novel design of the SE significantly reduced heat transfer from the top photothermal zone to the bulk water body without affecting rapid water delivery, thereby preventing salt deposition and improving energy efficiency. Under 1 light illumination, the water evaporation rate of the SE reached 2.94 kg m-2h−1 and 93 % evaporation efficiency. The water harvested via the engineered evaporation system is suitable for direct application in crop irrigation. This type of SEs may have commercial application potential in seawater desalination agricultural planting field, and wastewater treatment.

Joule-Heated Interfacial Catalysis for Advanced Electrified Esterification with High Conversion and Energy Efficiency.

Esterification reactions are crucial in industries such as chemicals, fragrances, and pharmaceuticals but often face limitations due to high reversibility and low reactivity, leading to restricted yields. In this work, an electrified esterification pathway utilizing a Joule-heated interfacial catalysis (JIC) system is proposed, where a hydrophilic, sulfonic acid-functionalized covalent organic framework grown on carbon felt (COF─SO3H@CF) acts as the interfacial catalyst, and the carbon felt serves as the electric heat source. This approach achieves an acetic acid conversion of 80.5% at a heating power density of 0.49Wcm-3, without additional reagents by vaporizing reaction products, surpassing the theoretical equilibrium limit of 62.5% by 1.29 times. Comprehensive analysis indicates that the intimate contact between the electric heat source and the COF─SO3H catalyst enables efficient, localized Joule heating directly at catalytic sites, minimizing thermal losses and allowing precise control over reaction interfaces. This finding demonstrates that this JIC system not only enhances esterification efficiency but may also offer a sustainable, energy-efficient pathway for high-yield chemical processes.

NIR Diradical-Featured Croconaine Nanoagent for Cancer Photoacoustic Imaging and Photothermal Therapy.

Radical-featured organic materials usually demonstrate significantly narrower bandgap than that of regular organic materials, which is beneficial for near-infrared (NIR) absorption and non-radiative decay process, making them good candidates for photothermal agents (PTAs) of photothermal therapy (PTT). However, most organic radicals are too short-lived to be separated and stable. Herein, a stable pyrylium-croconaine (CR) dye CR845 with high diradical character was synthesized and assembled into CR845 nanoparticles (NPs) to explore the photoacoustic imaging (PAI) and photothermal therapeutic performance under NIR irradiation in vitroand in vivo. CR845 exhibited a stable NIR absorption at 845 nm (ε= 3.37 × 105L mol-1cm-1) and a relatively high photothermal conversion efficiency (PCE) of 58.8%. When assembled into nanoparticles, CR845 NPs showed good photostability, good biocompatibility, favorable NIR photoacoustic potential, effective cancer cell killing and complete tumor elimination upon 850 nm laser irradiation. The work demonstrates a diradical-featured CR PTA with favorable PAI/PTT effects, which can help to provide new ideas for the development of NIR PTAs, and further promote the application of organic radical materials in the field of biomedicine.

Multi-objective optimization and dynamic characteristic analysis of solid oxide fuel cell - Supercritical carbon dioxide brayton cycle hybrid system

Solid oxide fuel cells (SOFCs) are widely used in distributed power generation systems due to their high energy conversion efficiency, low emissions. Therefore, investigating the dynamic characteristics of fuel cell integration systems is significant for ensuring the efficient and stable operation of SOFC integrated systems. In this study, an SOFC integrated system with a supercritical CO2 Brayton cycle as the bottoming cycle is proposed. A dynamic model is established to investigate the dynamic characteristics of this system under optimal operating conditions. This integrated system is optimized from the perspectives of two objectives: energy conversion efficiency and operational cost. Using the Pareto frontier, the optimal solutions are a system electrical efficiency of 61.21 % and a total cost rate of 4583.8 $/hour. These optimized results are used as steady-state design points for the integrated system. At the steady-state design point, flow and voltage perturbation simulation experiments are conducted on the integrated system to analyze the dynamic characteristics of key system parameters. This study provides a theoretical foundation for the control structure design of SOFC integrated systems.

Suppressed Non-Radiative Recombination in Formamidinium Lead Triiodide under Electric Activation.

The high carrier lifetime of metal halide perovskite (MHP) materials is closely related to the microscopic crystallographic structure. However, the detailed correlation between the lattice structure and carrier dynamics remains unclear. In this work, we found a correlation between lattice strain and open-circuit voltage (Voc) of MHP under electric activation. It is observed that the non-radiative recombination of MHP solar cells is progressively suppressed under elevated residual strain under an electric field. Moreover, the electric activation reduced the density of ions, which permanently switched off the ionic movement in the strained lattice structure. Resultantly, the Voc of cubic formamidinium lead triiodide under electric activation elevated to 1.21 V, which is only 59 mV lower than the theoretical limit of the material. This Voc represents one of the highest values for the same band gap of MHP. This resulted in a high power conversion efficiency (PCE) of 24.15%.

Janus Photothermal Films with Orientated Plasmonic Particle-in-Cavity Surfaces Enabling Heat Control in Solar-Thermal-Electric Generators.

Solar thermoelectric generators (STEGs) consisting of solar absorbers and thermoelectric generators (TEGs) can utilize solar energy to generate electrical power. However, performances of STEGs are limited by the heat losses of solar absorbers in air, which become more and more significant with an increase in the solar absorbing area. Herein, we describe the preparation of Au@AgPd nanostructure monolayer/poly(vinyl alcohol) (PVA) Janus photothermal films with broadband plasmonic absorption in the visible and near-infrared regions. By uniaxially stretching the Janus film, Au@AgPd can align along the stretching direction, which creates particle-in-cavity structures on the PVA surface. Benefiting from the oriented plasmonic particle-in-cavity configuration, the Janus films effectively convert sunlight into heat, trap the heat within their micrometer-depth structure, and facilitate its transfer along the direction of the nanostructure orientation. Integration of the Janus films with commercial TEGs allows thermal concentration onto a small thermoelectric surface, yielding an open-circuit voltage of 308 mV under 102 mW/cm2 natural sunlight illumination. Heat losses in commercial TEGs integrated with Janus films are reduced by approximately 50% while maintaining the same voltage output. Furthermore, incorporating the Janus films into a conventional STEG with carbon-based solar absorbers significantly enhances solar-thermal-electric conversion performance, achieving an output power density of 1.3 W m-2. Our design of Janus photothermal films with oriented particle-in-cavity surfaces can be extended to various solar-thermal systems for high-efficiency solar energy conversion and heat management.