Photothermal Process Research Articles

Heterogeneous alloyed CuSnO-DopaCube mediated photo-Fenton and photothermal synergistic catalysis for dye elimination

The Fenton/Fenton-like reaction is of significant importance in biomedical and environmental remediation applications. However, the use of Fenton/Fenton-like catalysts is limited due to incomplete light absorption, low energy conversion efficiency, and a narrow pH range. To address these issues, we have developed a photothermal-driven heterogeneous Fenton system using Cu2O-SnO2-Polydopamine (PDA) triple cubic heterostructures, which exhibit strong photothermal capabilities in the NIR region. The macromolecular PDA acts as a heat source for higher degradation efficiency due to its excellent photothermal conversion performance. Furthermore, our results show that the system significantly improves the energy conversion efficiency of Cu2O and exhibits excellent catalytic activity over a wide pH range by using Rhodamine B (RhB) as the model dye. This study offers a novel approach for environmental remediation through the synergistic effect of photocatalysis and photothermal processes.

Highly sensitive photodetector based on laser-generated graphene with 3D heterogeneous multiscale porous structures

Graphene holds great promise in optoelectronics because of its high broadband light absorption across a wide range of wavelengths. Despite low optical absorption, various techniques have been devised to address this challenge. This study presents a new highly sensitive, photodetector based on three-dimensional (3D) porous graphene derived from fluorinated polyimide (fPI-3DPG). This material is produced via a laser photothermal process and features micro- and nanopore structures that increase the light absorbing area and support optically resonant structures. The resulting fPI-3DPG photodetectors display high photoresponsivity of 4.4 mA W−1 in the visible light range, an ultrahigh signal-to-noise ratio of ∼208, and a noise equivalent power of 0.54 × 10−11 W Hz−1/2. These photodetectors are also mechanically durable, surviving 10,000 cycles of bending and twisting. The laser photothermal method used in this study enables fast, cost effective production of wearable and flexible optical sensors for imaging and spectroscopy applications, making this 3D graphene a promising functional material for sensing technologies.

Optical absorption and heat conduction control in high aspect ratio silicon nanostructures for photothermal heating applications

In photothermal heating, the temperature increase observed in an irradiated material is dependent on its optical absorption and thermal conductivity. A wide variety of studies have shown that optical absorption can be tailored using various nanostructures, including metamaterials, plasmonic structures, photonic crystals, and surface texturing. Similarly, thermal conductivity can be also tuned by nanostructures, including phononic crystals and superlattices. However, few have examined the potential for the simultaneous control of optical absorption and heat conduction to optimize photothermal heating processes. In this study, silicon hole and pillar arrays are tailored for their optical adsorption and thermal conductivity by varying their geometrical parameters. Subsequent experiments and numerical simulations reveal that the thermal conductivity of the nanostructures has a stronger influence on the photothermal heating effect than their optical absorption. Pillar arrays show a larger photothermal heating effect than the hole arrays; nevertheless, hole arrays are advantageous where connectivity is required, as in photothermal detector applications. With this understanding of the relationship between nanostructure dimensions and their photothermal properties, this analysis may guide the future design of periodic nanostructures for photothermal heating applications.

Activatable Immunoprotease Nanorestimulator for Second Near-Infrared Photothermal Immunotherapy of Cancer.

Photothermal immunotherapy is a combinational cancer therapy modality, wherein the photothermal process can noninvasively ablate cancer and efficiently trigger cancer immunogenic cell death to ignite antitumor immunity. However, cancer cells can resist the cytotoxic lymphocyte-mediated antitumor effect via expressing serine protease inhibitory proteins (serpins) to deactivate proteolytic immunoproteases. Herein, we report a smart polymer nanoagonist (SPND) with second near-infrared (NIR-II) phototherapeutic ablation and tumor-specific immunoprotease granzyme B (GrB) restimulation for cancer photothermal immunotherapy. SPND has a semiconducting polymer backbone grafted with a small-molecule inhibitor of serpinB9 (Sb9i) via a glutathione (GSH)-cleavable linker. Once in the tumor, Sb9i can be specifically liberated from SPND to inhibit serpinB9, restimulating the activity of GrB to enhance cancer immunotherapy. Moreover, SPND induces photothermal therapy for direct tumor ablation and immunogenic cancer cell death (ICD) under NIR-II photoirradiation. Therefore, such a smart nanoagonist represents a way toward combination photothermal immunotherapy (PTI).

Simple Laser-Induced Hexagonal Boron Nitride Nanospheres for Enhanced Tribological Performance

Hexagonal boron nitride, as a layered material with a graphite-like structure, exhibits good mechanical, lubricating and oxidation resistance properties, and is thus expected to become one of the top choices for green lubricating oil additives. However, its poor dispersibility in oil and difficulties in preparing spherical particles when constructing hexagonal boron nitride limit its application. In this paper, spherical hexagonal boron nitride nanoparticles are constructed via a simple laser irradiation method. Under laser irradiation, raw irregular hexagonal boron nitride particles were reshaped into nanospheres via a laser-induced photothermal process and rapid cooling in a liquid-phase environment. Under the optimal concentration, the coefficient of friction and wear spot diameter decreased by 26.1% and 23.2%, and the surface roughness and wear volume decreased by 29.2% and 23.8%, respectively. The enhanced tribological performance is mainly due to the ball bearing, depositional absorption and repair effect of the spherical particles. This simple laser irradiation method provides a new method by which to prepare spherical hexagonal boron nitride lubricating oil additives.

Mechanism of Cytotoxic Action of Gold Nanorods Photothermal Therapy for A549 Cell

Photothermal therapy has developed into an important field of tumor treatment research, and numerous studies have focused on the preparation of photothermal therapeutic agents, tumor targeting, diagnosis, and treatment integration. However, there are few studies on the mechanism of photothermal therapy acting on cancer cells. Here we investigated the metabolomics of lung cancer cell A549 during gold nanorod (GNR) photothermal treatment by high-resolution LC/MS, and several differential metabolites and corresponding metabolic pathways during photothermal therapy were found. The main differential metabolites contained 18-hydroxyoleate, beta-alanopine and cis-9,10-epoxystearic acid, and phosphorylcholine. Pathway analysis also showed metabolic changes involving cutin, suberine, and wax biosynthesis, pyruvate and glutamic acid synthesis, and choline metabolism. Analysis also showed that the photothermal process of GNRs may induce cytotoxicity by affecting pyruvate and glutamate synthesis, normal choline metabolism, and ultimately apoptosis.

Solar-to-H2 O2 Energy Conversion by the Photothermal Effect of a Polymeric Photocatalyst via a Two-Channel Pathway.

With a view to using solar energy, the exploitation of near-infrared (NIR) light, which constitutes about 50 % of solar energy, in photocatalytic H2 O2 synthesis remains challenging. In this study, resorcinol-formaldehyde (RF), which has a relatively low bandgap and high conductivity, is introduced for photothermal catalytic generation of H2 O2 under ambient conditions. Owing to the promoted surface charge transfer rate under high temperature, the photosynthetic yield reaches roughly 2000 μm within 40 min under 400 mW cm-2 irradiation with a solar-to-chemical conversion (SCC) efficiency of up to 0.19 % at 338 K under ambient conditions, exceeding the rate of photocatalysis with a cooling system by a factor of about 2.5. Notably, the H2 O2 produced by RF during photothermal process was formed via a two-channel pathway, leading to the overall promotion of H2 O2 formation. The resultant H2 O2 can be applied in situ for pollutant removal. This work offers a sustainable and economical route for the efficient formation of H2 O2 .

Broad-spectrum solar conversion towards photothermal catalytic reforming hydrogen production with in-situ thermal regulation over core-shell nanocomposites

Photothermal catalytic hydrogen production is regarded as an effective conversion of solar energy into clean energy carrier. However, the uncontrollable in-situ photo-thermal effect would cause overheating of the catalytic site, thereby reducing the electron transfer efficiency, and the vast amount of energy contained in the near-infrared thermal effect has not been fully utilized. In this study, an Au/TiO2 nanorod catalyst and n-eicosane were employed to establish a core-shell structure to enhance solar energy conversion and regulating in-situ temperature rise during the photothermal catalytic process. The results revealed that the core-shell structure offered an efficient reaction area and high dispersion stability, while the amount of photothermal catalyst loaded also influenced the photothermal catalytic performance. Also, the in-situ overheating is effectively regulated to help enhance efficient electron transfer for hydrogen production. The core-shell structures with Au/TiO2 loading amounts of 9.3%, 14.5%, and 20.2% enhanced hydrogen yields by 30.3%, 42.2%, and 53.8%, respectively, compared to that of pure photothermal catalyst suspension. Meanwhile, the photothermal conversion efficiencies were 33.3%, 64.5% and 88.1% higher than those of 10 vol% glycerol solution. Thus, the photothermal effect has been shown to be effective for improving the performance of photothermal glycerol reforming for hydrogen production, and photothermal catalyst-phase change material composite structures can provide a new idea for promoting solar energy into thermal and chemical energy.

Photothermal process and its stimulate healing performance for catalyst-free OCB/epoxy vitrimer composite

Polymeric coatings, widely used in large-scaled outdoor applications including solar energy collection, metal protection and so on, are limited by short service life caused by degradation and structural damage due to constant exposure in air and external force. Here, oxidized carbon black (OCB)/epoxy vitrimer (EV) composite without catalysts, dispersants and pre-heating was prepared by facile solvent mixing method. The addition of OCB improved the stress relaxation rate of the composite and endowed high solar absorptance (α) at 94.57% and solar thermal efficiency (η) at 93.28%. The efficiency of remote and local photothermal-stimulated healing for micro scratches of the composite coating was as high as 95.08%. And the macroscopic damage repairing which was rarely reported can be about 100% by a novel photothermal patching method. Meanwhile, the composites also have behaviors of shape memory, reusability and ion transfer barrier performance. Overall, based on the advantages of facile preparation, cheap raw materials, high solar absorptance and solar thermal efficiency and excellent remote and local healing efficiency, the OCB/EV composite coatings have potential applications in solar energy harvesting and provides a new strategy for the local and contactless repair of polymeric coatings used in outdoor applications such as solar-energy collector, solar absorption systems and metal protection, especially for the repair of the macroscopic damage.

Co nanoparticles modified N-doped carbon nanosheets array as a novel bifunctional photothermal membrane for simultaneous solar-driven interfacial water evaporation and persulfate mediating water purification

Solar-driven interfacial water evaporation is an effective way to produce clean freshwater. However, it is still challenging that volatile organic compounds might enter the condensate in the evaporation process. Herein, we designed a novel bifunctional photothermal membrane (Co-N-C/CF) that can be applied for simultaneous water evaporation and persulfate mediating water purification. Due to the molecular thermal vibrations effect of carbon-based materials, plasmonic effect of Co NPs, the membrane exhibited an impressive water evaporation rate of 1.88 kg m−2 h−1 (1 sun irradiation). Furthermore, Co-N-C/CF could effectively activate persulfate for phenol (PE) removal through a non-radical reaction process. Experiments and density functional theory calculations illustrated that PE is favorable to be degraded while water molecules are easier to be converted into vapor in the photothermal evaporation process. Hence, the combination of persulfate-based oxidation and solar-driven water evaporation shows great application potential in the durable and efficient production of clean water.

Structural Color Generation on Transparent and Flexible Substrates by Nanosecond Laser Induced Periodic Surface Structures

AbstractLaser patterning to fabricate micro/nanoscale structures attracts enormous attention as they find many functional applications owing to their controllable structure and unique properties. The present work proposes a unique solution‐based method to fabricate laser‐induced periodic surface structure (LIPSS) patterns on a thin film of Titanium (IV) butoxide and Ag organometallic (OM) solution‐coated glass substrates with near infra‐red (NIR) nanosecond (ns) laser. The formation of periodic patterns has been confirmed, the thin film solution concentration affects the LIPSS pattern thickness and a continuous pattern is achieved with the diluted solution. Parametric studies demonstrate that the LIPSS patterns could be achieved with optimal solution dilution, laser fluence, scan speed, and pulse duration. A high power and faster scan speed result in discontinued, and defective patterns. The photothermal process such as material reorganization followed by electromagnetic absorption that takes place during laser patterning is mainly responsible for the fabrication of controlled structures. LIPSS patterned surfaces exhibit iridescent surface coloration while illuminated with white light, and the color spectrum from red to blue is distinguished. LIPSS patterned substrates serve as mold and structures are transferrable to the poly dimethyl siloxane (PDMS) film and exhibit iridescent structural coloration like LIPSS patterned substrates.

Reactor design for solar-driven photothermal catalytic CO2 reduction into fuels

Proper reactor design is of vital importance for highly-efficient photothermal catalytic CO2 reduction into solar fuels. With respect to the whole chain from capturing solar energy through energy and mass transfer to the final reduction of CO2 into fuels, this work proposes a systematic model of elaborately designing solar-driven photothermal catalytic reactors based on comprehensively studying the broadband light harvesting, energy and mass transport, and chemical conversion processes in the entire reduction of CO2 by harnessing solar energy. The established numerical model including the optical and electrical simulations of the catalyst nanoparticle as well as the flow, thermal, and chemical reaction field in the reactor is developed to integrate the overall process of the photocatalytic CO2 reduction, so as to analyze the effectiveness of the reactor and further obtain the optimal design strategy. Based on the analysis of the calculated results, methods are put forward to promote the chemical reaction by changing various parameters to regulate the light capture, radiation transfer, temperature field, and reactant supply in the catalyst layer. Most importantly, the designed reactor shows solar energy harnessing-conversion capability with remarkable light absorptivity, energy confinement, and reactants enrichment characteristics, thus realizing outstanding catalytic performance. This innovative reactor design strategy could greatly facilitate the solar-driven photothermal catalytic CO2 reduction process.

Multifunctional AIE Nanosphere-Based "Nanobomb" for Trimodal Imaging-Guided Photothermal/Photodynamic/Pharmacological Therapy of Drug-Resistant Bacterial Infections.

Injudicious or inappropriate use of antibiotics has led to the prevalence of drug-resistant bacteria, posing a huge menace to global health. Here, a self-assembled aggregation-induced emission (AIE) nanosphere (AIE-PEG1000 NPs) that simultaneously possesses near-infrared region II (NIR-II) fluorescence emissive, photothermal, and photodynamic properties is prepared using a multifunctional AIE luminogen (AIE-4COOH). The AIE-PEG1000 NPs were encapsulated with teicoplanin (Tei) and ammonium bicarbonate (AB) into lipid nanovesicles to form a laser-activated "nanobomb" (AIE-Tei@AB NVs) for the multimodal theranostics of drug-resistant bacterial infections. In vivo experiments validate that the "nanobomb" enables high-performance NIR-II fluorescence, infrared thermal, and ultrasound (AB decomposition during the photothermal process to produce numerous CO2/NH3 bubbles, which is an efficient ultrasound contrast agent) imaging of multidrug-resistant bacteria-infected foci after intravenous administration of AIE-Tei@AB NVs followed by 660 nm laser stimulation. The highly efficient photothermal and photodynamic features of AIE-Tei@AB NVs, combined with the excellent pharmacological property of rapidly released Tei during bubble generation and NV disintegration, collectively promote broad-spectrum eradication of three clinically isolated multidrug-resistant bacteria strains and rapid healing of infected wounds. This multimodal imaging-guided synergistic therapeutic strategy can be extended for the theranostics of superbugs.

Dynamic Thermal Transport Characteristics of a Real-Time Simulation Model for a 50 MW Solar Power Tower Plant

A dynamic simulation model of a heliostat field and molten salt receiver system are developed on the STAR-90 simulation platform. In addition, a real-time simulation model coupling the above two models is built to study the photothermal conversion process of Delingha’s 50 MW solar power tower plant. The nonuniform and time-varying characteristics of the energy flux density on the receiver surface and the dynamic characteristics under different operating conditions are studied. The operational process of the receiver of a typical day is simulated. It was found that there was a strong positive correlation between the energy flux and DNI, and the maximum energy flux density on the surface of the heat absorbing tube panel moved from the first tube panel to the fourth in sequence from 12:00 to 18:00. At the same time, the energy flux density of the last four panels decreased gradually along the arrangement order of the panels. DNI, molten salt mass flow rate and inlet temperature step disturbance simulations are carried out, and the response curves of the molten salt outlet temperature and tube wall temperature are obtained. The conclusion of this paper has important guiding significance for the establishment of an operational strategy for photothermal coupling in a molten salt solar power tower plant.

Response of excited microelongated non-local semiconductor layer thermomechanical waves to photothermal transport processes

Response of excited microelongated non-local semiconductor layer thermomechanical waves to photothermal transport processes

Nanostructured Materials for Photothermal Carbon Dioxide Hydrogenation: Regulating Solar Utilization and Catalytic Performance.

Converting carbon dioxide (CO2) into value-added fuels or chemicals through photothermal catalytic CO2 hydrogenation is a promising approach to alleviate the energy shortage and global warming. Understanding the nanostructured material strategies in the photothermal catalytic CO2 hydrogenation process is vital for designing photothermal devices and catalysts and maximizing the photothermal CO2 hydrogenation performance. In this Perspective, we first describe several essential nanomaterial design concepts to enhance sunlight absorption and utilization in photothermal CO2 hydrogenation. Subsequently, we review the latest progress in photothermal CO2 hydrogenation into C1 (e.g., CO, CH4, and CH3OH) and multicarbon hydrocarbon (C2+) products. Finally, the relevant challenges and opportunities in this exciting research realm are discussed. This perspective provides a comprehensive understanding for the light-heat synergy over nanomaterials and instruction for rational photothermal catalyst design for CO2 utilization.

Photothermally Promoted Photoisomerization of Naphthopyran-Based Dyes to Achieve Sensitive Photodeformation under Sunlight

The exploration of photodeformation materials toward sunlight is essential for their application in soft robots and medical technology. However, until now, the sunlight-driven deformation is still confronted with challenges, which is hard to be realized with high sensitivity by either photothermal or photoisomerization process independently. In this text, through the rational combination of photothermal and photoisomerization properties by naphthopyran-based dyes, the sunlight-driven contraction can be achieved with good fatigue resistance. Moreover, through the precise modulation of molecular configurations and electronic properties, the sensitive photodeformation toward sunlight has been achieved with a contraction of 50% and a bending angle of 118°. This work provides a convenient approach to construct sunlight-driven soft actuators via a photothermally promoted photoisomerization process.

Experimentally validated numerical model of multi-spectral bands radiative transport in solar receiver/reactor with photo-active porous absorber reacting media

Solar energy efficient utilization such as solar thermal energy storage and thermochemical conversion technologies is an effective way of closing carbon cycles with systematic green environmental remediation. Understanding the complexity of induced light with its spectrum and intensity feature is crucial for the further optimization of the solar system using a more advanced concept such as photothermal catalysis. This study discussed the radiation transfer processes in detail and clarified the principles and assumptions underlying the photothermal effect in the solar receiver/reactor. In addition, the phenomenon of radiation absorption through the porous interface is discussed and the solution of the equivalent surface is given out. Based on the above discussion, a two-bands numerical model is established with various numerical methods to adapt the properties of different surfaces and irradiation sources. The numerical model is validated by experimental data and used to estimate both spectra and intensity transfer characteristics through the solar reactor. The analysis of optimal operation condition, distribution coefficient, spectral feature of glasses, and thermal-optical performance are presented based on advanced numerical model. This study deepens the understanding of radiative transfer mechanisms in solar energy conversion systems and provides pioneering theoretical guidance with an advanced numerical method for the further optimization of a system-level photothermal catalysis process.

High‐Efficiency and Low‐Intensity Threshold Femtosecond Laser Direct Writing of Precise Metallic Micropatterns on Transparent Substrate

AbstractLaser direct writing (LDW) is a promising approach for fabricating metallic micropatterns on transparent substrates for transparent electronic circuits that satisfy both electronic and optical criteria. However, high efficiency and precision patterning remain a challenge for both photochemical and photothermal LDW. Herein, a novel method is proposed with a femtosecond laser to achieve a highly‐efficient photothermal process via single‐photon absorption by photosensitive particles (SPA‐FsLDW). The dispersive photosensitive particles act as numerous heating sources, enabling simultaneous multiple‐location photothermal reactions and highly‐efficient metallization due to heat‐induced metal ion reduction. The new approach effectively exploits the excellent heat‐input regulation with the ultrashort pulse of the femtosecond laser to achieve great temperature controllability and precision. It is shown that, with a deposition rate of ≈107 µm3 s−1 and electrical resistivity of ≈10−7 Ω m, SPA‐FsLDW improves efficiency and electrical resistivity by at least one order of magnitude compared to previously reported FsLDW. A self‐powered sensor is fabricated using SPA‐FsLDW, demonstrating its practical applicability.

Nd3+/Sm3+ codoped NaLa(WO4)2 glass ceramic: A novel optical heater

Transparent Nd3+/Sm3+ codoped tungstate silicate glass ceramics were prepared and used for the photothermal conversion process. XRD patterns, TEM image and the enhanced Raman signals confirm the appearance of the tetragonal scheelite NaLa(WO4)2 nanocrystals in the vitreous phase. In comparison to the precursor glass, the enhancement of photoluminescence of Nd3+ ions in the glass ceramics attributes to the enrichment of Nd3+ ion in the precipitated low phonon-energy tetragonal scheelite NaLa(WO4)2 nanocrystals. The rapid reduction of photoluminescence of Nd3+ ions in the Nd3+/Sm3+ codoped glass ceramics demonstrates that a strong energy transfer from Nd3+ to Sm3+ takes place, which provides more non-radiative relaxation channels and is beneficial for the improving the photothermal conversion efficiency. Under the irradiation of 808 nm laser diode, a significant temperature rise is observed in the Nd3+/Sm3+ codoped glass ceramics and may be used as a good optical heater.