High Light Absorption Research Articles

Theoretical Designing of Atomically Precise MgO/TiO2(001) Quantum Dot-Sensitized Solar Cell for High Visible Light Absorption and Fast Charge Injection

Theoretical Designing of Atomically Precise MgO/TiO₂(001) Quantum Dot-Sensitized Solar Cell for High Visible Light Absorption and Fast Charge Injection

Salt-rejecting 3D cone flowing evaporator based on bilayer photothermal paper for high-performance solar seawater desalination

Solar energy-driven water evaporation technology is a promising, low-cost and sustainable approach to alleviate the global clean water shortage, but usually suffers from low water evaporation rate and severe salt deposition on the water evaporation surface. In this work, a hydrophilic bilayer photothermal paper-based three-dimensional (3D) cone flowing evaporator was designed and prepared for stable high-performance seawater desalination with excellent salt-rejecting ability. The as-prepared bilayer photothermal paper consisted of MXene (Ti3C2Tx) and HAA (ultralong hydroxyapatite nanowires, poly(acrylic acid), and poly(acrylic acid-2-hydroxyethyl ester)). The accordion-like multilayered MXene acted as the efficient solar light absorber, and ultralong hydroxyapatite (HAP) nanowires served as the thermally insulating and supporting skeleton with a porous networked structure. A siphon effect-driven unidirectional fluid transportation unit in the 3D cone flowing evaporator could guide the concentrated saline flowing away from the evaporating surface to prevent salt deposition on the evaporation surface, avoiding severe deterioration of the performance in solar water evaporation. Furthermore, combining high solar light absorption and high photothermal conversion efficiencies, low water evaporation enthalpy (1838 ± 11 J g−1), and additional energy taken from the ambient environment, the as-prepared cone flowing evaporator exhibited a high water evaporation rate of 3.22 ± 0.20 kg m−2 h−1 for real seawater under one sun illumination (1 kW m−2), which was significantly higher than many values reported in the literature. This study provides an effective approach for designing high-performance solar energy-driven water evaporators for sustainable seawater desalination and wastewater purification.

Two-dimensional Janus SnS/MoSi2N4 structure for high-efficiency photocatalytic splitting

Energy consumption and environmental pollution need us to explore new and sustainable energy sources. Photocatalytic water splitting for hydrogen production offers one of the most effective solutions to this problem. Identifying an advanced photocatalyst is essential to achieve high-efficiency photocatalytic water splitting. We observed that the SnS/MoSi2N4 van der Waals heterostructure (vdWH) is a viable candidate for photocatalytic water splitting using density functional theory (DFT). Our investigation has revealed that the SnS/MoSi2N4 vdWH exhibits type-II band alignment, which is highly advantageous for spatially separating photoexcited electron-hole pairs. Remarkably, this type-II band arrangement remains stable across different stacking forms of the vdWH. Meanwhile, SnS/MoSi2N4 vdWH exhibits high light absorption ability. After considering the Janus effect, we have ascertained that SnS/MoSi2N4 vdWH likely possesses appropriate band edge positions for facilitating water splitting. Moreover, we revealed that bandgap and light absorption of SnS/MoSi2N4 vdWH could be further improved by applying the strain while SnS/MoSi2N4 vdWH still maintains the appropriate band edge positions. The results suggest that SnS/MoSi2N4 vdWH is an ideal photocatalyst for water splitting.

High-performance CsSnBr<sub>3</sub>/Si PN heterojunction photodetectors prepared by pulsed laser deposition epitaxy

Halide perovskite semiconductors have outstanding physical properties such as high light absorption coefficient, large carrier diffusion length, and high photoluminescence quantum efficiency, and demonstrate significant potential applications in optoelectronic devices such as photodetectors and solar cells. However, the toxicity and environmental instability associated with lead-based perovskites significantly limit their applications. An attractive solution is substituting tin for lead in perovskites and growing high-quality tin-based perovskite films. In this study, we adopt the pulsed laser deposition method to achieve the epitaxial growth of CsSnBr<sub>3</sub> films on silicon substrates. The morphologies, optical and electrical properties of the CsSnBr<sub>3</sub> films, as well as the CsSnBr<sub>3</sub>/Si heterojunction detectors, are comprehensively investigated with various characterization techniques, including XRD 2<i>θ</i>-<i>ω</i> and <i>φ</i> scans, atomic force microscope, scanning electron microscope, photoluminescence and time-resolved photoluminescence spectroscopy, and Hall electrical measurements. The results indicate that such a CsSnBr<sub>3</sub> film grows epitaxially onto the silicon substrate via a face-to-face mode. Interestingly, an unusual temperature-dependent bandgap increase is found to be due to the high electron effective mass of CsSnBr<sub>3</sub>. The CsSnBr<sub>3</sub> film shows the P-type semiconductor behavior with a high mobility of 122 cm²/(V·s), enabling the formation of an ideal Type-II heterojunction with the silicon substrate. The CsSnBr<sub>3</sub>/Si semiconductor heterojunction detector exhibits distinctive heterojunction PN diode characteristics in the dark and a pronounced photoresponse under illumination. At zero bias, the detector displays a switch ratio exceeding 10<sup>4</sup>, responsivity of 0.125 mA/W, external quantum efficiency of 0.0238%, detectivity (<inline-formula><tex-math id="Z-20240301150440">\begin{document}$D^* $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231645_Z-20240301150440.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231645_Z-20240301150440.png"/></alternatives></inline-formula>) of 2.1×10<sup>9</sup> Jones, response time 3.23 ms, and recovery time of 4.87 ms. Under a small bias of –1 V, the switch ratio decreases to 50, but responsivity and external quantum efficiency increase by 568 times. The detectors can maintain self-powered operation state with a high switch ratio of 10<sup>4</sup>, millisecond-level response time and millisecond-level recovery time. In conclusion, this work presents a self-powering, high-performance photodetector based on CsSnBr<sub>3</sub> epitaxial films integrated with silicon substrates.

Enhanced photocatalytic water splitting with two-dimensional van der Waals heterostructures of BAs/WTeSe

DFT predicts stable boron arsenide-Janus monolayer heterostructures with tunable bandgaps, high light absorption, and good carrier mobility, making them ideal for photocatalytic water splitting.

Towards scalability for metal halide perovskites photovoltaics

Perovskite solar cells (PSCs) have gained significant attention in recent years due to the inherent properties of perovskite materials, such as bandgap tunability, high tolerance to defects in the structure, high light absorption, efficient charge transportation, flexibility, and cost-effectiveness. Although for a long time the development of PSCs has relied primarily on solution-based coating techniques, the recent advances in the field of PSCs have moved the attention of both researchers and companies toward thermal evaporation (TE) techniques, especially due to the high compatibility of these processes with the industrial production of PSCs. Indeed, TE has many advantages, such as high reproducibility, film uniformity, low material consumption, absence of toxic solvents, and easy scalability of the device. In this review, after a brief overlook of the most popular solution-based PSC fabrication methods, we illustrate the TE technique for small and large areas.

High-performance WS2/ZnO QDs heterojunction photodetector with charge and energy transfer

Two-dimensional/zero-dimensional (2D/0D) van der Waals heterojunctions have become a research hotspot for novel optoelectronic devices by virtue of their high light absorption and fast transportation. In previous studies, researchers preferred...

Photoelectric sensors constructed based on nanomaterials and their applications

Photoelectric sensors are electronic components that use the photoelectric effect to convert optical signals into electrical signals and are widely used in industrial automation, environmental monitoring, medical devices, and other fields. With continuous progress in fields such as information technology, material science, and manufacturing technology, optoelectronic sensor technology has developed rapidly. Nanomaterials have broad application prospects in optoelectronic sensors due to their unique properties. On the one hand, nanomaterials can enhance the electromagnetic field of light, leading to charge separation and enhanced electron transport, thereby achieving higher photoelectric conversion efficiency. On the other hand, nanomaterials have a larger specific surface area and higher light absorption and photosensitivity. In addition, due to the small size of nanomaterials, their surface energy has a greater impact and their response to the environment is more sensitive. This makes optoelectronic sensors based on nanomaterials a current research hotspot. Therefore, this article mainly introduces photoelectric sensors constructed using nanomaterials and their applications. This article first introduces various optoelectronic sensors made of nanomaterials, including inorganic semiconductors, organic photovoltaic materials, and two-dimensional materials. In addition, its applications in food safety, environmental monitoring, and medical fields were emphasized. It has reference significance for the development of future photoelectric sensors.

Enhanced performance of a Na3.5Co4[Bi2Co2W19.75O70(H2O)6]/porous graphitic carbon nitride heterojunction based photocatalyst realized by the addition of copper sulfide nanoparticles.

Photocatalytic hydrogen (H2) evolution can effectively solve the global energy problem, in which the key factor is the synthesis of efficient photocatalytic materials. In this study, we successfully synthesized a novel photocatalyst, BiWCo/CuS/PGCN, by functionalizing porous graphitic carbon nitride (PGCN) with sandwich-type polyoxometalate Na3.5Co4[Bi2Co2W19.75O70(H2O)6]·39.5H2O (BiWCo) and introducing copper sulfide (CuS) nanoparticles as a cocatalyst. This approach was aimed at enhancing the built inner electric field between interfaces, resulting in a significant improvement in photocatalytic H2 evolution performance. This research adopts a step-by-step method to synthesize BiWCo/CuS/PGCN composites with p-n heterojunctions, which has high visible light absorption and a synergistic effect of multiple elements. PGCN with a high specific surface area contributes to the uniform distribution of active sites. In addition, the nano-CuS cocatalyst provides abundant active sites and more electron transfer pathways for photocatalysis. Therefore, the H2 production efficiency of BiWCo/CuS/PGCN is 6.3 times that of PGCN, 4.5 times that of BiWCo and 2.5 times that of BiWCo/PGCN under visible light. The H2 production rate of BiWCo/CuS/PGCN reaches 3477.58 μmol g-1 h-1. At the same time, the ternary photocatalyst shows high stability after 30 hours and 5 cycles. This work demonstrates that BiWCo/CuS/PGCN has good application prospects in H2 evolution, and provides a new strategy for the design of efficient ternary photocatalytic materials.

La/Fe bimetallic MOF-derived p-LaFeO3/n-CdS heterojunction: efficient photocatalytic degradation of organic contaminants and adsorption isotherms

Designing efficient catalysts with strong redox characteristics and high visible light absorption in the field of photocatalysis.

Enhanced electron transport and optical properties of experimentally synthesized monolayer Si9C15: a comprehensive DFT study for nanoelectronics and photocatalytic applications.

Two-dimensional silicon-carbide (SixCy) materials stand out for their compatibility with current silicon-based technologies, offering unique advantages in nanoelectronics and photocatalysis. In this study, we employ density functional theory and nonequilibrium Green's function methods to investigate the electronic properties, electron transport characteristics, and optoelectronic qualities of experimentally synthesized monolayer Si9C15. Utilizing the modified deformation potential theory formula, we unveil Si9C15's significant directional anisotropy in electron mobility (706.42 cm2 V-1 s-1) compared to holes (432.84 cm2 V-1 s-1) in the a direction. The electrical transport calculations reveal that configurations with a 3 nm channel length demonstrate an ON state when biased, reaching a peak current of 150 nA. Moreover, this maximum current value escalates to 200 nA under tensile strain, marking an increase of approximately 100 times compared to the 5 nm channel, which remains in an OFF state. Si9C15 exhibits high light absorption coefficients (∼105 cm-1) and suitable band edge positions for water splitting at pH 0-7. Applying 1-5% tensile strain can tune the conduction band minimum and valence band maximum closer to the standard redox potentials, enhancing photocatalytic water splitting efficiency. Remarkably, under illumination at pH 0 and 7, Si9C15 can spontaneously catalyze water splitting, demonstrating its potential as a highly efficient photocatalyst. Our findings emphasize the importance of strain control and device length optimization for performance enhancement in nanoelectronics and renewable energy applications, positioning Si9C15 as a promising material for high-performance field-effect transistors and photocatalytic water splitting.

High‐performance Self‐powered Ultraviolet‐visible‐near infrared Broadband Photodetectors Based on Sb2Se3/TiO2 Heterojunctions and Multifunctional Applications

AbstractHigh‐performance broadband photodetectors (PDs) are essential components in spectroscopy, remote sensing, imaging, and light communication applications. In this paper, Sb2Se3 nanoparticles (NPs) are uniformly deposited on TiO2 nanorod arrays (NRs) to construct a type II heterojunction with good interfacial contact by a simple two‐step potentiostatic electrochemical deposition method combined with N2 atmosphere annealing at 280, 290 and 300 °C to control the amount of Se in Sb2Se3. A good interfacial contact between Sb2Se3 and TiO2 is conducive to the separation and transport of photogenerated carriers. Sb2Se3/TiO2 PDs exhibit excellent self‐powered photoresponse in a broad spectral range from ultraviolet‐visible‐near infrared (UV‐VIS‐NIR) due to the combined effects of high light absorption, low defect density, and more suitable band alignment. The optimal parameters with a responsivity of 13.48 A W−1, detectivity of 7.9 × 1011 Jones, and response time of 18/20 µs are demonstrated for the PDs annealed at 290 °C. The excellent performance broadband Sb2Se3/TiO2 PDs are used to construct the application models in the light communication for light encryption and flaw detection. This work opens up a new strategy for Sb2Se3/TiO2 PDs in multifunctional applications.

Carbon nanotube-based photothermal membrane for efficient cold air heating and removal of particulate matter and airborne bacteria

Indoor heating results in high energy consumption and severe atmospheric pollution. Although the development of solar air heaters provides a sustainable route for indoor thermal comfort, such heaters still face challenges in terms of adequate heat exchange and filtering of atmospheric pollutants. Inspired by solar-driven interfacial evaporation, we propose a multifunctional carbon nanotube-based photothermal membrane for efficient cold air heating and purification via ventilation. Carbon nanotubes endow the membrane with high light absorption and thermal conversion capabilities, thereby sufficiently heating the approaching cold air. With the hierarchical structure formed by phase inversion, the thin upper skin of the composite membrane intercepts micropollutants via the size-sieving effect, whereas the finger-like pores and interpenetrating macrovoids inside the membrane ensure that the heated clear air passes through quickly. A proof-of-principle experiment indicated a cold airflow of 1 L/min across the membrane, yielding a temperature increase of ca. 37 °C as well as a PM 2.5 rejection always higher than 93%. Further antibacterial experiments demonstrated that the membrane effectively removed airborne bacteria. This multifunctional carbon nanotube-based photothermal membrane with specific microstructures not only improves the indoor living quality but also provides a sustainable development scheme to coordinate the relationship among energy utilization, building heating, and air purification.

Silicon distyryl-BODIPY hybrid photodiode: moving a step ahead from organic interface layer to type II band alignment

Organic-inorganic heterojunctions are becoming an attractive topic of research for their applications in hybrid photodetectors, solar cells, resistive switching memory devices etc. The easy chemical synthesis and low-cost fabrication for organic thin films come with the benefit of high light absorptivity, high fluorescence quantum yield and band gap tunability along with high charge carrier lifetime that could be combined with the existing silicon-based technology. In this aspect, various organic dyes utilised as an interfacial layer with silicon Schottky junction are reported earlier. However, the photo responses are quite limited. Here, in this report, a Type II Silicon/Distyryl-BODIPY p-n junction has been proposed as an organic-inorganic hybrid photodetector which has not been explored extensively yet. The transformation from a mere organic interfacial layer to band aligned junction enhances the charge carrier separation providing higher photo-responsive behaviour. With the simple spin-coating technique, the Distyryl-BODIPY derivative with phenolic functionalities is coated to fabricate the p-n junction diode. To further improve the performance, pyramidal surface texturization on silicon is deployed using wet chemical etching that supplements the light absorption with internal reflections. Both the devices have been investigated for their photo-response characteristic where a high photo-responsivity of 4353 A W−1 is attained for the textured device as compared to 118 A W−1 for the planar silicon device at a − 3 V bias with an ultra-high specific detectivity of 1012 Jones and 1010 Jones respectively. The behaviours of interfacial states have been demonstrated using the capacitance (C), conductance (G) and series resistance (RS) vs voltage (V) curves at different frequencies. Further calculations of interfacial state density revealed the existence of 1000 times higher interfacial states in planar device leading to lower performance as compared to pyramidal device. The findings in this report suggest that dye-based organic-inorganic heterostructures find potential applications in photodetectors and other optoelectronic devices.

Solar-thermal anisotropic zeolitic imidazolate framework/reduced graphene oxide hybrid aerogels for efficient clean-up of heavy crude oil

Heavy crude oil rich in colloid and asphaltene is widely used in human life, but the collection and clean-up of its spills are difficult because of its high viscosity and low flowability. Herein, the zeolitic imidazolate framework-8/reduced graphene oxide (ZIF-8/RGO) hybrid aerogels are prepared by in situ anchoring ZIF-8 particles onto anisotropic RGO aerogel for efficient clean-up of spilled heavy crude oil. The solar-thermal ZIF-8/RGO hybrid aerogel with numerous vertical microchannels is efficient in decreasing viscosity and improving flowability of heavy crude oil because of the high solar light absorption and solar-thermal energy conversion capabilities of the RGO and the increased solar light diffuse reflection path and hydrophobicity of the aerogel by ZIF-8. Under 1-sun irradiation, the surface temperature of the aerogel reaches rapidly to 70 °C within 1 min. At the same time, the viscosity of the heavy crude oil falls quickly from 105 to 103 mPa s, and the maximum adsorption capacity of heavy crude oil reaches 112 g g−1 within 9 min. Moreover, the hybrid aerogel exhibits satisfactory adsorption and cycling ability to various organic solvents and oily media. The excellent solar-thermal energy conversion and high adsorption capacities make the anisotropic aerogel promising for efficient clean-up of spilled heavy crude oil.

Structural properties and photocatalytic activity of amorphous-crystalline TiO2 thin films

TiO2-coated glass plates were prepared by dip coating using TiO2 coating sol with a mixed amorphous and crystalline structure. These samples were dried at 100°C or calcined at 500°C, which were referred to as MT and CT, respectively. The TiO2 thin films on glass plates were characterized by X-ray diffraction, thermogravimetry-differential thermal analysis, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy, Brunauer-Emmett-Teller surface area measurement, scanning electron microscopy, and ultraviolet–visible diffuse reflectance spectra. The TiO2 thin films of MT samples had mixed amorphous and crystalline structures, while those of CT samples had only crystalline structures. The photocatalytic activity of the samples was investigated on the basis of methylene blue (MB) decomposition under ultraviolet and visible light irradiation. In the dark stabilization, MT samples had a higher MB adsorption capacity than CT samples. MT samples had a smaller amount of anatase TiO2 than CT samples, but both glass plate samples showed the same MB photocatalytic activity under ultraviolet light irradiation. We presumed that these results were because the amorphous-crystalline TiO2 thin films had a high specific surface area, so they had more adsorption and active sites. Under visible light irradiation, only the MT samples had photocatalytic activity, which can be attributed to their high visible light absorbance, which may be due to their peroxo groups, disordered structure, and larger specific surface area.

Layered-Defect Perovskite K3Bi2X9 (X = I, Br, and Cl) Thin Films for CO2 Photoreduction: An Analysis of Their Pseudocatalytic Behavior

Lead-free layered-defect perovskite K3Bi2X9 (X = I, Br, and Cl) films were proposed as efficient photocatalysts for the CO2 reduction reaction (CO2RR) to obtain clean and sustainable formic acid (HCOOH), a widely used feedstock in the industry. The films exhibited high crystallinity, hexagonal morphologies, and visible light absorption, which were modified by proportionally increasing the diameter of the X anion. The obtained photocatalytic activities showed values of 299 µmol h−1 (K3Bi2Br9), 283 µmol h−1 (K3Bi2I9), and 91 µmol h−1 (K3Bi2Cl9). However, the stability of the films is an important parameter that must be solved; therefore, three strategies were implemented—one with an intrinsic approach (solvent engineering) and two others with an extrinsic focus (substrate modification and heterojunction engineering). These modifications favored yields of up to 738 µmol h−1 and constant production over 6 h, demonstrating that the perovskite maintains continuous HCOOH generation. The analysis of the reaction medium showed the degradation of the material structure to BiOI and K+, which could have enhanced its affinity towards CO2. In this manner, the degraded perovskite (K3Bi2I9/BiOI) might still react with the CO2 to generate HCOOH in an aqueous medium under visible light, showing pseudocatalytic behavior.

Efficient indoor dye-sensitized solar cells based on TiO2 hollow sphere

The upcoming successful commercialization of dye-sensitized solar cells as is conditioned by the improvement of the device performance and durability. One of promising strategies exploited so far is co-sensitization, which involved the development of the dyes with high light absorption together with high expensive photovoltage redox mediators. Here, we propose a different strategy to improve ambient light harvesting capacity and durability using the three-dimensional hollow sphere architecture of the photoanode, commercial XY1b dye, and common iodide/triiodide redox electrolyte. Under 1000 lux illumination, TiO2 hollow spheres obtained by near-supercritical solvothermal synthesis with tuning shell thickness provided a power conversion efficiency of 25.25%, which is a 56.6% increase comparable to dispersed nanoparticles used in classical dye-sensitized solar cells. Together with the dye loading capacity and light scattering efficiency, the TiO2 hollow spheres improved the long-term stability of the cell under indoor lighting conditions. Thus, even after 720 h of operation, the DSSC continued to provide a stable short-circuit current with a moderate increase, approximately 10% from the initial value.

Synthesis of Metal-Organic Framework-Based ZIF-8@ZIF-67 Nanocomposites for Antibiotic Decomposition and Antibacterial Activities.

Toxic antibiotic effluents and antibiotic-resistant bacteria constitute a threat to global health. So, scientists are investigating high-performance materials for antibiotic decomposition and antibacterial activities. In this novel research work, we have successfully designed ZIF-8@ZIF-67 nanocomposites via sol-gel and solvothermal approaches. The ZIF-8@ZIF-67 nanocomposite is characterized by various techniques that exhibit superior surface area enhancement, charge separation, and high light absorption performance. Yet, ZIF-8 has high adsorption rates and active sites, while ZIF-67 has larger pore volume and efficient adsorption and reaction capabilities, demonstrating that the ZIF-8@ZIF-67 nanocomposite outperforms pristine ZIF-8 and ZIF-67. Compared with pristine ZIF-8 and ZIF-67, the most active 6ZIF-67@ZIF-8 nanocomposite showed higher decomposition efficacy for ciprofloxacin (65%), levofloxacin (54%), and ofloxacin (48%). Scavenger experiments confirmed that •OH, •O2-, and h+ are the most active species for the decomposition of ciprofloxacin (CIP), levofloxacin (LF), and ofloxacin (OFX), respectively. In addition, the 6ZIF-67/ZIF-8 nanocomposite suggested its potential applications in Escherichia coli for growth inhibition zone, antibacterial activity, and decreased viability. Moreover, the stability test and decomposition pathway of CIP, LF, and OFX were also proposed. Finally, our study aims to enhance the efficiency and stability of ZIF-8@ZIF-67 nanocomposite and potentially enable its applications in antibiotic decomposition, antibacterial activities, and environmental remediation.

Photocatalytic water splitting properties of GeC/InS van der Waals heterostructure: first-principles calculations

Based on first-principles, we conducted an in-depth study of the GeC/InS van der Waals heterostructure formed by GeC and InS and discussed its structure, electronic properties and optical properties. First, we observe that this heterostructure has negative binding energy, indicating that the interlayer interactions are mainly affected by van der Waals forces. Through band structure and density of state analysis, we confirmed its type-II band alignment characteristics, which means that photogenerated carriers have the ability to automatically separate in space. Moreover, the average charge density difference and Bader charge analysis show that there is a built-in electric field in the heterostructure, and further proves that GeC/InS forms a Z-scheme charge transfer mechanism. Interestingly, the band edge position spans the water redox potential and can fully induce the redox reaction of water splitting, indicating that it is a potential photocatalyst. The high light absorption coefficient shown in the absorption spectrum also further confirms its excellent photocatalytic activity. The most striking thing is that the solar hydrogen production efficiency of GeC/InS heterostructure is as high as 44.39%. Our research demonstrates the theoretical basis for GeC/InS heterostructure as a photocatalyst.