Photothermal Energy Research Articles

Sustainable solar-powered seawater desalination enabled by phosphorene-decorated watermelon-like phase-change microcapsules

Solar-powered interfacial evaporation is considered as an emerging innovative technology for seawater desalination; however, it suffers from insufficient evaporation efficiency under intermittent solar irradiation. Aiming at realizing sustainable solar-powered seawater desalination for clean water production, we have designed a new type of watermelon-like phase-change microcapsules as a photothermal absorbent material for a solar interfacial evaporator. This type of phase-change microcapsules was prepared through rational layer-by-layer microencapsulation with a ZrO2 nanoparticle-containing n-docosane core as a phase-change material (PCM) for solar photothermal harvest and prompt thermal response, a ZrO2 shell for the leakage prevention of the molten n-docosane core, and a polydopamine coating layer together with its surface-decorated phosphorene nanoflakes for high-efficient sunlight absorption and fast water transportation. The resultant microcapsules are featured by a watermelon-like microstructure as confirmed by transmission electron and scanning electron microscopy. They also exhibit a high light absorption efficiency of 84.95 %, a high latent heat capacity of 146.2 J g−1, and good wettability. Equipped with the watermelon-like phase-change microcapsules, the developed solar interfacial evaporator obtained an evaporation rate of 3.09 kg m−2 h−1 under one-sun illumination for seawater desalination. The PCM core within the microcapsules can store solar photothermal energy as latent heat under sufficient solar irradiation and then release it under evaporation conditions without sunlight illumination, thus enhancing the water evaporation efficiency. This enables the developed evaporator to increase its total evaporation mass by 31.5 % on a cloudy day in comparison with the conversional solar evaporator without a PCM, indicating a remarkable enhancement in the evaporation performance under intermittent solar irradiation. The developed solar interfacial evaporator exhibits great potential for application in sustainable solar-powered seawater desalination.

Hydrothermally synthesized cobalt oxide/polydimethylsiloxane based photothermal absorber for superior thermal energy conversion and water evaporation application

Solar-driven interfacial evaporation has garnered worldwide interest in recent years due to its unique vapor generating capacity using sustainable solar energy. Many photoabsorber have been studied for conversion of photothermal energy and heat absorption. Unfortunately, the majority of the absorber materials in supply are pricey, and the installation procedures tend to be intricate. This research focuses on the ongoing difficulty of creating cost-efficient photothermal materials that have excellent light absorption and simple manufacturing processes. We created a novel composites coated with Cobalt oxide and polydimethylsiloxane (Co3O4/PDMS) which successfully produce energy and purify water utilizing an extensive spectrum of solar energy. Hydrothermally synthesized Co3O4 particles exhibit distinct optical properties in the UV–Vis region due to ligand field transitions and charge transfer between Co2⁺ and Co³⁺ ions. Additionally, these particles exhibits a strong absorption in the NIR region due to the intervalence charge transfer and d-d transitions, enhancing their photothermal activity. This culminates in outstanding light-to-heat transformation in the Co3O4/PDMS composite, which maintains a surface temperature of 42.7 °C compared to 33.7 °C for pristine PDMS under standard 1 sun intensity for 5 min. The flexible Co3O4/PDMS composite transfers solar energy to electric energy, producing ∼99 mV with 1 sun irradiation, while bare PDMS only achieved a voltage of 61 mV under 1 sun circumstances. An efficient double layer Co3O4/PDMS@MF sponge achieved an evaporation rate of 1.33 kg m−2 h−1 with the photothermal conversion efficiency of 68.8 %. These results motivate thorough investigation in photothermal potential of Co3O4, revealing the promising possibilities for harnessing solar-thermal energy and presents a novel method for using solar power to purify water and generate electricity.

Understanding photo-thermal and melting mechanisms in optical charging of nano and micro particles laden organic PCMs

Engineering efficient optical charging process necessitates efficient photo-thermal energy conversion, transfer, as well as storage of the incident solar radiant energy. The present work is a determining step in deciphering, quantifying, and understanding the aforementioned steps involved in the optical charging of PCMs. Herein, the effect of particle size, concentration and thermochromism have been critically investigated. In particular, detailed optical characterization and photo-thermal experimentation pertinent to non-thermochromic nanoparticles laden PCM (referred to as NP-PCM) and thermochromic micro capsules laden PCM (referred to as TMCP-PCM) has been undertaken. Detailed optical analysis points out that opposed to NP-PCM, TMCP-PCM significantly scatter the incident radiations – the diffuse transmittance (at room temperature) in the two cases being approximately 2 % and 39 % respectively. Furthermore, whereas, optical properties of non-thermochromic nanoparticles are nearly invariant to temperature changes; in the case of thermochromic microcapsules, the magnitude of scattering further increases and diffuse transmittance reaches as high as 51 % at elevated temperatures. Although, thermochromism helps in enhancing the penetration depth at elevated temperatures, but, due to significant fraction of scattering, the photo-thermal energy conversion is not that effective. In terms of temperature field, spatial-temporal temperature distribution curves reveal that temperature spread (in the liquid phase) in case of optical charging of non-thermochromic particles (carbon soot nanoparticles) laden PCMs is significantly high (as high as approximately 24 °C) relative to that observed in case of thermochromic particles (microcapsules) laden PCMs (approximately, 4 °C). The magnitude of the temperature spread (being representative of the deviation from thermostatic optical charging) clearly points out that opposed to non-thermochromic laden PCMs, nearly thermostatic optical charging can be achieved in case of thermochromic particles laden PCMs.Furthermore, in case of optical charging without thermochromic assistance, the temperature spread, peak temperatures and the melting rates increase with increase in particles concentration. Whereas, in the latter case, although the temperature spread and peak temperatures are nearly independent; the melting rates do depend on the particles’ concentration. Overall, the present work is a significant step towards accelerated-thermostatic thermal energy storage.

Retraction Note: Demodulating an acoustic signal stimulated by photo-thermal elastic energy conversion using quartz tuning forks

Retraction Note: Demodulating an acoustic signal stimulated by photo-thermal elastic energy conversion using quartz tuning forks

Enhancing Photothermal Energy Transduction through Inter- and Intramolecular Interactions of Multiple Two-Photon Dyes Appended onto Calix[4]arene.

Organic dyes-based photothermal agents (OPTAs) have received increasing attention as alternative to inorganic materials due to their higher biocompatibility and extensive diversification. Maximizing nonradiative deexcitation channels is crucial to improve the photothermal conversion efficiency (PCE) of OPTAs. This is typically achieved through individual molecular design or collective enhancement using supramolecular strategies. Furthermore, photothermal therapy (PTT) generally relies on linear one-photon absorption of the light source by the OPTA, with less consideration given to nonlinear two-photon absorption (2PA) strategies, despite their potential benefits. Here, a synergistic strategy, which combines intramolecular and intermolecular quenching, is employed to maximize the photothermal efficiency of diphenylamino-substituted distyryl dicyanobenzene (DSB), an outstanding two-photon-absorbing chromophore. One to three DSB units have been introduced on the conic p-tert-butyl-calix[4]arene (CX), serving as a preorganizing platform to allow aggregate formation and promote intramolecular quenching within the multichromophoric systems. Importantly, the multichromophoric molecules had very high two-photon absorption capabilities with cross sections (δ2PA) reaching maximal values of 3290 GM at 810 nm. Experimental data accompanied by large-scale molecular dynamics simulations and time-dependent density functional theory calculations shed light onto the interaction mechanism in those multiple DSB-appended CX compounds to rationalize their optical properties. Then, the formulation with Pluronic F127 amphiphile yields water-dispersible nanoprecipitates (Nps), in which the PCE is further maximized and the photobleaching is reduced due to the combination of intra- and intermolecular quenching. The high two-photon absorption in the near-infrared (NIR) window associated with the high PCE of these nanosized OPTAs could serve as a basis to future in vivo 2P-PTT applications.

Photothermally enhanced ion-transport in solid-state, non-Faradic energy storage devices for sub-freezing operability

The universal direct dependence of ionic mobility on temperature severely restricts the low-temperature operation of energy storage devices. We overcome this limitation by synergizing photothermal conversion with electrochemical energy storage, using non-graphitizable nanocarbon florets (NCF) as multi-functional electrodes. NCF-based supercapacitors leverage the photothermal energy, directing it to the High Internal Phase Emulsion polymer (poly-HIPE) infused ionic conductor [BMIm]-[TFSI], resulting in 15% increase in specific capacitance (Csp) at 30 °C and a 45% at −30 °C. This is the first solid-state energy storage device usable at sub-freezing conditions (< − 4 °C) without compromising its performance. Importantly, the device exhibits identical characteristics at 10 °C (with sunlight) and 30 °C (in the dark), thereby offsetting a temperature difference of 20 °C. Experimental evidences points to the reduction in electrolyte resistance by 86% and 34% in relaxation time constant as the origin of such improved functioning. Furthermore, the advantage of processability is translated to configurational form-factor to efficiently heat the ionic conductor and thereby realise a 15% increase in Csp.

Poly-dopamine coated-cellulose/chitosan hybrid carbon aerogel composite phase change materials with efficient photothermal conversion and storage

Solar energy, being both low-cost and renewable, is a viable alternative for thermal storage and can help mitigate the energy crisis. Efficient conversion and storage for solar energy can significantly enhance energy utilization. Phase change materials (PCMs), such as paraffin (PW), are capable of harvesting and converting solar energy into thermal energy, thus playing a crucial role in solar energy utilization. However, PW faces challenges, such as solid–liquid leakage and low photothermal conversion efficiency, which hinder its applications in solar energy storage. In this study, we proposed the construction of a robust poly-dopamine (PDA)/chitosan (CS)/cellulose nanofibers (CNF) carbon aerogel with enhanced photothermal performance. This is achieved by incorporating PDA, known for its excellent light absorption properties, and cross-linking it with low-cost biomass CS and CNF via a Schiff base reaction. The resulting novel composite PCMs exhibit high photothermal conversion efficiency and shape stability by encapsulating PW within the PDA/CS/CNF carbon aerogel. Our findings demonstrate that the composite PCMs have a high melting energy-storage capacity of 209.57 J/g. Notably, the introduction of PDA significantly improved the photothermal conversion efficiency by 94.9 %. These results suggest that composite PCMs hold great potential for applications in photothermal energy conversion and storage.

Photo-thermal effects initiate multi-level energy conversion in “solid-solid” phase-changing fibers

The current textiles primarily employ passive heat barriers to minimize heat loss and achieve effective thermal insulation for human beings. Accordingly, intelligent fibers with energy storage and temperature control capabilities have garnered significant attention due to their potential to revolutionize textile technology. The study integrates the photo-thermal effect and phase change energy storage materials onto a fiber, thereby fabricating a fully intelligent energy storage fiber. This innovation enables the multi-level conversion of sunlight: “Optical energy - Thermal energy - Phase transition energy - Thermal energy”. The intelligent fiber efficiently converts solar energy into heat energy through the photo-thermal coupling of CuNPs, subsequently inducing a spatial conformational change in the solid-solid phase change material within the fiber for effective heat storage. The hybrid fiber possesses enhanced mechanical properties but also exhibits a significantly high phase transition enthalpy value of 49.75 J g−1 and a phase transition temperature suitable for human body temperature (20.19–30.21 °C), especially the fiber is more durable. The photo-thermal conversion test vividly demonstrates the systematic transformation of four distinct forms of energy within the composite fiber. This approach holds significant potential for advancing the field of smart fiber technology.

Efficiently all-weather anti-icing and de-icing coatings enabled by polyaniline microcapsules encapsulated phase change materials

Photothermal superhydrophobic coatings are one of the most promising anti-icing/de-icing materials. However, the intermittence of light energy limits the application of photothermal energy conversion technologies when continuous de-icing is required. Herein, an innovative solution for the integration of photothermal effect and phase change thermal storage was proposed. In this work, an efficient anti-icing/de-icing coating was successfully fabricated based on multifunctional polyaniline microcapsule encapsulating butyl stearate (BS). Benefiting from the heat storage capacity of BS in the microcapsule, the coating could achieve all-weather anti-icing capability. Under the condition of −20 °C, the freezing time of water droplets on the coating with only 10 wt% microcapsules was delayed by about 12.6 times compared to the blank coating. At the same time, under simulated dark conditions, the freezing time of water droplets could be delayed by about 14.1 times. Moreover, owing to the thermal conductivity and high solar energy exploitation, polyaniline endowed the coating with outstanding photothermal de-icing performance, presenting the superiority of outdoor applications. Under NIR (200 mW/cm2) illumination, the melting time of water droplets was reduced to 18 s, which was nearly 10 times faster than that on the blank coating. Moreover, the polyaniline microcapsules also possessed outstanding anticorrosion property, which was particularly attractive for mental coating applications. The combined properties of this all-weather anti-icing and de-icing coating could render it a promising contender for challenging outdoor applications.

An Innovative Azobenzene-Based Photothermal Fabric with Excellent Heat Release Performance for Wearable Thermal Management Device.

Azobenzene (azo)-based photothermal energy storage systems have garnered great interest for their potential in solar energy conversion and storage but suffer from limitations including rely on solvents and specific wavelengths for charging process, short storage lifetime, low heat release temperature during discharging, strong rigidity and poor wearability. To address these issues, an azo-based fabric composed of tetra-ortho-fluorinated photo-liquefiable azobenzene monomer and polyacrylonitrile fabric template is fabricated using electrospinning. This fabric excels in efficient photo-charging (green light) and discharging (blue light) under visible light range, solvent-free operation, long-term energy storage (706 days), and good capacity of releasing high-temperature heat (80-95 °C) at room temperature and cold environments. In addition, the fabric maintains high flexibility without evident loss of energy-storage performance upon 1500 bending cycles, 18-h washing or 6-h soaking. The generated heat from charged fabric is facilitated by the Z-to-E isomerization energy, phase transition latent heat, and the photothermal effect of 420nm light irradiation. Meanwhile, the temperature of heat release can be personalized for thermal management by adjusting the light intensity. It is applicable for room-temperature thermal therapy and can provide heat to the body in cold environments, that presenting a promising candidate for wearable personal thermal management.

Carbon-intercalated halloysite-based aerogel efficiently encapsulating phase change materials with excellent photothermal conversion and energy storage

Latent heat storage systems based on organic phase change materials (PCMs) are considered to be an efficient solar energy utilization strategy, but leakage vulnerability and insensitivity to sunlight of PCMs limit their further application in energy storage. In this work, a new hierarchical porous aerogel was constructed with the carbon intercalated halloysite nanotubes (CHNTs) as the assembly units for PCMs encapsulation to improve the load weight, stability and sunlight absorption. The CHNTs were first successfully synthesized through intercalation and carbonization, with the aim of increasing their specific surface area and sunlight absorption.Subsequently, the CHNTs/polyvinyl alcohol (PVA) aerogels with 3D honeycomb structure were prepared by self-assembly using a freeze-drying method, which can significantly promote the encapsulation ratio of lauric acid (LA) in the pores of both aerogels and CHNTs. The CHNTs can not only improve compressive strength of the aerogels and shape stability of the composite PCMs, but also enhance light absorption ability of the composites compared to pristine HNTs. As a support material, CHNTs aerogel (CHNP) loaded more than 92 wt% PCM (LA@CHNP) and exhibited an extremely high latent heat capacity (170.9 J/g). The LA@CHNP had good structural and thermal stability in 300 cycles without visible leakage. Besides, solar energy absorption increased from 43 % to 98 %, and the solar-to-thermal energy conversion efficiency increased to 95.88 %, which could be attributed to 3D porousness and carbon nanolayers of the CHNTs. We have successfully synthesized an eco-friendly and facile composite LA@CHNP, which will contribute to the design of advanced composites with excellent solar energy storage properties, and provide a new direction for the application of carbonized materials.

Optically manipulated nitrate-salt-based direct absorption solar collectors for a photothermal energy harvesting system

This study introduces a nitrate-salt-based direct absorption solar collector (DASC) for a photothermal energy harvesting system with efficient solar energy harvesting and the reduction of thermal radiation loss. Investigations of the optical properties of snow-like solid-state binary nitrate salt in solar and thermal infrared (IR) spectral regions were first conducted in this study. Research revealed that the solid-state binary nitrate salt showcases high solar reflectivity (>90 %) and infrared emissivity (∼0.85), leading to a cooling power of 36.4 W m−2. This implies pure solid salt cannot gain energy from solar illumination. To tackle this, the proposed system incorporated nano graphite and a hot mirror. Consequently, the absorbed solar energy increased from 67.6 W m−2 to 898.7 W m−2, resulting in a heating power of 794.0 W m−2 under AM 1.5G solar irradiance. With the proposed approaches, melting the salt with lowest solar concentration ratio of 15 (∼12.5 kW m−2) was achieved.

Tunable electrical/thermal output performance of the PV/T system with magnetic nanofluid based spectral beam filter

The photovoltaic/thermal systems with magnetic nanofluid based spectral beam filter would achieve thermal decoupling and utilize the full spectrum to minimize energy loss. The prepared Fe3O4 magnetic nanofluid was introduced into this system as selective absorbing fluid filter. An external magnetic field was added to manipulate the distribution behavior of nanoparticles that affect the optical characteristics of magnetic nanofluids could meet the various application requirements for electrical/thermal output of the photovoltaic/thermal system. The optical properties of magnetic nanofluid with various nanoparticle distribution behaviors under the varying magnetic field were tested by UV–visible spectrophotometric and Finite-Difference Time-Domain simulated respectively. Furthermore, the effect of magnetic nanoparticle concentration and magnetic field strength on the electrical/thermal output performance of the photovoltaic/thermal system was studied. The results show the higher nanoparticle concentration enhances the thermal output of the system but reduces the electrical output, accompanied by a significant reduction in the surface temperature of the cell. Both photothermal and photovoltaic conversion efficiencies are increased below 100mT magnetic field due to the transmission in the response spectrum of monocrystalline silicon cell increase under the formation of chain structure of the nanoparticles. It is concluded that the photothermal, photovoltaic, and total solar energy conversion efficiencies are respectively 59.82%, 13.98%, and 73.75% at 0.0025 wt% concentration under 100 mT magnetic fields, and its function of merit value was increased by 109% compared to the system without spectral beam filter.

Dissecting Exciton Dynamics in pH‐Activatable Long‐Wavelength Photosensitizers for Traceable Photodynamic Therapy

AbstractTumor‐specific activatable long‐wavelength (LW) photosensitizers (PSs) show promise in overcoming the limitations of traditional photodynamic therapy (PDT), such as systemic phototoxicity and shallow tissue penetration. However, their insufficient LW light absorption and low singlet oxygen quantum yield (Φ 1O2) usually require high laser power density to produce thermal energy and synergistically enhance PDT. The strong photothermal radiation causing acute pain significantly reduces patient compliance and hinders the broader clinical application of LW PDT. Through the exciton dynamics dissection strategy, we have developed a series of pH‐activatable cyanine‐based LW PSs (LET‐R, R = H, Cl, Br, I), among which the activated LET‐I exhibits strong light absorption at 808 nm and a remarkable 3.2‐fold enhancement in Φ 1O2 compared to indocyanine green. Transient spectroscopic analysis and theoretical calculations confirmed its significantly promoted intersystem crossing and simultaneously enhanced LW fluorescence emission characteristics. These features enable the activatable fluorescence and photoacoustic dual‐modal imaging‐escorted complete photodynamic eradication of tumors by the folic acid (FA)‐modified LET‐I probe (LET‐I‐FA), under the ultralow 808 nm laser power density (0.2 W cm−2) for irradiation, without the need for photothermal energy synergy. This research presents a novel strategy of dissecting exciton dynamics to screen activatable LW PSs for traceable PDT.

Near-infrared-II photocharging nanozyme for enhanced tumor immunotherapy

In tumor therapy, copper (Cu)-based nanozymes with peroxidase-like activity play a crucial role in converting hydrogen peroxide into hydroxyl radicals (OH). This process induces immunogenic cell death, which in turn activates the body’s immune response, enhancing the efficacy of tumor immunotherapy. Nonetheless, the efficiency of this reaction is curtailed due to the oxidation of Cu(I) to Cu(II), leading to the self-depletion of the nanozyme’s activity and an insufficient yield of OH for effective immunotherapeutic activation. To surmount this challenge, our research introduces a photocharging self-doped semiconductor nanozyme, copper sulfide (Cu9S8). The photocharging effect enables the nanozyme to convert internal Cu(II) back to Cu(I) through charge transfer induced by near-infrared (NIR)-II photothermal energy, thereby effectively maintaining the enzyme-like activity of the nanozyme. Additionally, Cu9S8 is enhanced with a calcium sulfide (CaS) coating. This coating reacts in the acidic microenvironment of tumors to generate hydrogen sulfide (H2S) gas, which in turn suppresses the catalase activity inherent in tumor cells, ensuring a plentiful supply of H2O2 for the nanozyme’s operation. This dual strategy of amplifying enzyme-like activity and substrate availability culminates in the generation of ample OH within tumor cells, leading to significant immunogenic cell death and thereby realizing potent immunotherapy.

A promising approach utilising photothermal energy to disinfect the root canal system: An invitro investigation.

This study aimed to assess root canal disinfection through various irrigation protocols, including a novel photothermal system called 'LEAP'. Mandibular premolars were infected with Enterococcus faecalis and divided into five groups for different treatments: Group 1: standard needle irrigation; Group 2: passive ultrasonic irrigation; Group 3: GentleWave; Group 4: LEAP; and Group 5: Group 1 + Group 4. Microbial counts were measured before (S1) and after disinfection (S2) using colony-forming units (CFU) and confocal laser scanning microscopy (CLSM). Results revealed a significant reduction in bacterial counts for all groups (p < 0.05). While the percentage of dead bacteria near the canal wall (0-50 μm) did not differ significantly, at 50-150 μm, LEAP and SNI + LEAP exhibited significantly higher bacterial reduction than other groups (p < 0.05). The findings indicate that LEAP is comparable to existing irrigation devices in the main root canal and notably superior in tubular disinfection.

RuCo/ZrO2 Tandem Catalysts with Photothermal Confinement Effect for Enhanced CO2 Methanation.

Photothermal CO2 methanation reaction represents a promising strategy for addressing CO2-related environmental issues. The presence of efficient tandem catalytic sites with a localized high-temperature is an effective pathway to enhance the performance of CO2 methanation. Here the bimetallic RuCo nanoparticles anchored on ZrO2 fiber cotton (RuCo/ZrO2) as a photothermal catalyst for CO2 methanation are prepared. A significant photothermal CO2 methanation performance with optimal CH4 selectivity (99%) and rate (169.93mmol gcat -1 h-1) is achieved. The photothermal energy of the RuCo bimetallic nanoparticles, confined by the infrared insulation and low thermal conductivity of the ZrO2 fiber cotton (ZrO2 FC), provides a localized high-temperature. In situ spectroscopic experiments on RuCo/ZrO2, Ru/ZrO2, and Co/ZrO2 indicate that the construction of tandem catalytic sites, where the Co site favors CO2 conversion to CO while incorporating Ru enhances CO* adsorption for subsequent hydrogenation, results in a higher selectivity toward CH4. This work opens a new insight into designing tandem catalysts with a photothermal confinement effect in CO2 methanation reaction.

Organic cocrystals: From high‐performance molecular materials to multi‐functional applications

AbstractAdvancements in organic electronics are propelling the development of new material systems, where organic materials stand out for their unique benefits, including tunability and cost‐effectiveness. Organic single crystals stand out for their ordered structure and reduced defects, enhancing the understanding of the relationship between structure and performance. Organic cocrystal engineering builds upon these foundations, exploring intermolecular interactions within multicomponent‐ordered crystalline materials to combine the inherent advantages of single‐component crystals. However, the path to realizing the full potential of organic cocrystals is fraught with challenges, including structural mismatches, unclear cocrystallization mechanisms, and unpredictable property alterations, which complicate the effective cocrystallization between different molecules. To deepen the understanding of this promising area, this review introduces the mechanism of organic cocrystal formation, the various stacking modes, and different growth techniques, and highlights the advancements in cocrystal engineering for multifunctional applications. The goal is to provide comprehensive guidelines for the cocrystal engineering of high‐performance molecular materials, thereby expanding the applications of organic cocrystals in the fields of optoelectronics, photothermal energy, and energy storage and conversion.

Layered laser-engraved wood-based composite capable of photothermal conversion and energy storage for indoor thermal management in buildings

Wood is used more and more in building. Phase change materials (PCM) with automatic temperature regulation and heat storage function have been widely concerned in the field of building energy conservation. However, phase-change materials have poor light induction and cannot absorb sunlight during the day in time, resulting in limited heat storage effect. For the purpose of achieving efficient energy collection and utilization, a laser-engraved method was employed in this study to directly generate a three-dimensional grid structure on the surface of wood. Then, the eutectic mixture of capric acid (CA) and stearic acid (SA) and nano-SiO2 composite PCM (CPCM) was impregnated into the supporting substrate with photothermal conversion capability. The obtained laser-engraved wood (LEW) loaded with CA-SA/Nano-SiO2 showed a latent heat of 64.706 J/g, a thermal conductivity of 0.732 W/(m⋅K) and a photothermal conversion efficiency of 64.46 %. Additionally, the three-dimensional porous structure of wood and the addition of nano-silica set up a double barrier for the leakage of PCM. Therefore, CPCM have prospective applications as indoor thermal insulation materials. In this research, a simple laser engraving method was adopted to endow the wooden substrate with photothermal conversion ability, which provides an idea to expand the application of photothermal conversion materials in the field of phase-change energy storage. In addition, the building simulation software validated the potential of CPCM in stabilizing indoor temperatures and reducing building energy consumption.

Dissecting Exciton Dynamics in pH-Activatable Long-Wavelength Photosensitizers for Traceable Photodynamic Therapy.

Tumor-specific activatable long-wavelength (LW) photosensitizers (PSs) show promise in overcoming the limitations of traditional photodynamic therapy (PDT), such as systemic phototoxicity and shallow tissue penetration. However, their insufficient LW light absorption and low singlet oxygen quantum yield (Φ 1O2) usually require high laser power density to produce thermal energy and synergistically enhance PDT. The strong photothermal radiation causing acute pain significantly reduces patient compliance and hinders the broader clinical application of LW PDT. Through the exciton dynamics dissection strategy, we have developed a series of pH-activatable cyanine-based LW PSs (LET-R, R = H, Cl, Br, I), among which the activated LET-I exhibits strong light absorption at 808 nm and a remarkable 3.2-fold enhancement in Φ 1O2 compared to indocyanine green. Transient spectroscopic analysis and theoretical calculations confirmed its significantly promoted intersystem crossing and simultaneously enhanced LW fluorescence emission characteristics. These features enable the activatable fluorescence and photoacoustic dual-modal imaging-escorted complete photodynamic eradication of tumors by the folic acid (FA)-modified LET-I probe (LET-I-FA), under the ultralow 808 nm laser power density (0.2 W cm-2) for irradiation, without the need for photothermal energy synergy. This research presents a novel strategy of dissecting exciton dynamics to screen activatable LW PSs for traceable PDT.