Remarkable Light Absorption Research Articles

Synthesis and Design Strategies of MXene Used as Catalysts

AbstractMXene have found extensive applications in various fields, including catalysis. Two predominant roles of MXene in catalysis are as catalyst carriers or as catalysts themselves. The former has received significant attention and is addressed in other publications. This review assesses MXene and its derivatives as direct catalysts, which is particularly intriguing due to its potential to reduce the design cost of catalysts. Moreover, an in‐depth discussion of this aspect aids in understanding the true role of MXene in catalysis, beyond its role as a catalyst carrier. For instance, MXene and its derivatives have been extensively employed as photocatalysts, with their catalytic activity significantly influenced by their structural characteristics. Furthermore, due to MXene's remarkable light absorption capacity, it is crucial to explore the contributions of photothermal generation or photocatalytic‐thermocatalytic synergistic effects. Additionally, MXene has demonstrated remarkable electrocatalytic performance in hydrogen production. Moreover, MXene exhibits promising applications in thermal catalysis, such as dehydrogenation and oxidation. A deeper understanding of these aspects can help researchers further design MXene‐based nanomaterials, or alleviate their oxidation. Finally, we offer insights into the future research directions of MXene from our perspective. This review could provide guidance for the design of novel MXene catalysts for industrial applications.

Investigating the optoelectronic properties of Mn and Fe doped CuAlS₂ for intermediate band solar cell applications

Chalcopyrites demonstrate compelling features for optoelectronic and photovoltaic devices, attributed to their valuable properties. Their remarkable light-absorption capabilities and well-suited band gap render them so attractive for applications in these fields. By allowing low-energy sub-bandgap photons to pass through and reducing the thermalisation loss from high-energy photons, intermediate-band materials address the primary problems in solar cells. This approach allows for more efficient use of the solar spectrum, helping solar cells exceed the traditional efficiency limits defined by the Shockley-Queisser limit. The objective of this study was to evaluate the electronic and optical characteristics of CuAlS2 systems doped with transition metals (TM = Mn, Fe) using the Full Potential Linearized Augmented Plane Wave approach within the framework of Density Functional Theory. A stable phase within the systems was observed upon replacing the Al atom with TM. The functionality of the intermediate band was governed by the 3d electronic characteristics of the TM3+ ion and its electronic configuration. The optical properties of CuAlS2 doped with Mn and Fe were analysed by calculating the dielectric function, refractive index, reflectivity, and absorption coefficient. Furthermore, the introduction of Mn and Fe through doping led to the creation of an intermediate band, enhancing visible light absorption and power conversion efficiency. Consequently, the optical spectrum of Mn-doped CuAlS2 and Fe-doped CuAlS2 compounds exhibits additional absorption peaks, accompanied by a significant improvement in absorption intensity. Our findings highlighted the need for continued and futuristic research into the scalability of these materials for practical applications in solar cells, optoelectronics, and spintronic devices. This investigation suggests that Mn-doped CuAlS2 holds the highest potential due to its high charge carriers and low recombination rate, indicating enhanced performance in CuAlS2-based intermediate band solar cells.

A self-floating and windproof Janus biomass composite hydrogel with magnetic controllability and salt rejection for polluted seawater desalination

To alleviate the global freshwater crisis, a self-floating magnetic Janus biomass composite hydrogel has been fabricated through a rational asymmetric bilayer structure design, which exhibits many merits such as remarkable light-absorption, photothermal conversion, water-evaporation, salt rejection, wind-resistant, etc. Specifically, sodium alginate, cellulose nanofibrils (from corn straw), and acrylic acid were crosslinked by triple interpenetrating networks (chemical cross-linking, ionic cross-linking and hydrogen bonding). Janus hydrogel evaporator was constructed by incorporating the top layer containing light-absorbing core–shell magnetic nanoparticles (Fe3O4@PDA NPs), and the bottom layer composed of self-floating foam gel due to the addition of foaming agent. Under one solar irradiation, the average evaporation rate and photothermal conversion efficiency of Janus biomass composite hydrogel reached 2.89 ± 0.09 kg·m−2·h−1 and 95.66 ± 2.68 %, respectively. Its evaporation stability and salt tolerance capability have been demonstrated by extended period of simulated desalination. Furthermore, Janus biomass composite hydrogel also had excellent mechanical property (ultimate stress of 1.6 MPa) and magnetic performance, which can not only effectively resist the stress induced by wind and waves, but also enable the magnetic maneuvering and wind-resistance floating on the sea. When the input voltage of electromagnet was 24 V, the furtherest response displacement and maximum resisted wind speed were 9 cm and 7.2 m/s, respectively. Therefore, such magnetic self-floating Janus biomass composite hydrogel serving as interfacial solar-driven evaporator system offers a green, efficient and sustainable solution for clean freshwater production.

Preparation and performance enhancement of MXene/Na2HPO4·12H2O@SiO2 phase change microcapsule

Currently, the leakage problem of phase change materials can be solved by the microencapsulation technology. Inorganic hydrated salt materials have the advantages of high latent heat density, high thermal conductivity and low cost. How to construct inorganic hydrated salt microcapsules with excellent heat storage capacity and photothermal conversion performance maintains a challenge. In this work, the MXene/Na2HPO4·12H2O@SiO2 (MXene/MPCMs) composite phase change microcapsules were designed and prepared. The Na2HPO4·12H2O was directly used as phase change material and TEOS was used as raw material to generate SiO2 wall material. The MXene played a key and important role in simultaneously enhancing their photothermal conversion efficiency while maintaining available latent heat. The prepared composite microcapsules (MPCM-1) showed more obvious heat storage and release characteristics, and the latent heat reached 169.62 J/g. Besides, when the hydrated salt was encapsulated in silica shell, the supercooling degree of hydrated salt was reduced from 14.2 °C to 10.1 °C. With the increase of MXene content, the maximum surface temperature of microcapsules significantly increased. Based on the results of surface temperature distribution, the photothermal conversion ability and heat transfer rate of microcapsules were effectively improved, which was mainly attributed to the remarkable light absorption conversion ability of MXene. When the MXene was added, the MXene/MPCMs still showed excellent heat storage properties (∼ 156.64 J/g). At the same time, the MXene/MPCMs showed good chemical compatibility, crystallization characteristics and thermal stability. Considering available performance enhancement, the prepared microcapsules show good application prospect in solar energy utilization.

Replacing the electron-hole transport layer with doping: SCAPS simulation of lead-free germanium-based perovskite solar cells based on CsGeI3

In recent years, scientists have shown increasing interest in perovskite solar cells because of their remarkable light absorption capabilities and promising prospects, among which germanium-based perovskite solar cells have been praised for non-toxicity. However, the defects between the charge transport layers affect its performance, and the charge transport layer materials also bring environmental hazards due to some organic properties. In this work, we propose to replace the charge transport layer with a solar cell based entirely on the germanium-based perovskite absorption layer by varying the CsGeI3 doping concentration. We created n-CsGeI3 and p-CsGeI3 layers conducive to electron hole transport, thus effectively reducing the defects between the interface transport layers, improving the electron hole transport environment, and improving the transmission efficiency. We employed SCAPS software for designing and optimizing the cell structure, enabling us to model and fine-tune parameters such as band gap, thickness, doping concentration, and defect density. These optimizations led to the calculation of optimal values, resulting in an impressive 34.57 % efficiency. The cell structure developed in this work validates the feasibility of germanium-based perovskite solar cells without electron hole transport layer, reducing environmental risks and optimizing performance parameters to some extent. This provides a valuable reference for future research on such solar cells.

First-principles studies on the electronic and photocatalytic water splitting properties of surface functionalized Y2C-based MXenes.

Recently, MXenes, an emerging family of two-dimensional (2D) materials, have attracted increasing interest for photocatalytic water splitting due to their various excellent physical and chemical properties, such as large specific surface area, good hydrophilicity, and remarkable light absorption ability. However, the photocatalysts of MXenes with symmetric structures are limited by rapid recombination of photo-generated carriers and the prerequisite of a large band gap no less than 1.23 eV. Differently, Janus MXenes with different surface functional groups facilitate the separation of photo-generated electrons and holes with the help of the intrinsic electric field. And, at the same time, there is no prerequisite for the band gap of Janus MXene photocatalysts as long as they possess appropriate band edge positions. Here, we explored the structural, electronic and photocatalytic water splitting properties of symmetric Y2CT2 and Janus Y2CTT' MXenes (T, T' = H, F, Cl, OH) using the density functional theory (DFT) method. Our calculations show that all the investigated Y2CT2 are not suitable photocatalysts for photocatalytic water splitting at all pH values (pH = 0, 7, and 14). In contrast, all the investigated Janus Y2CTT' MXenes are good water splitting photocatalysts with high optical absorption coefficients and remarkable solar-to-hydrogen (STH) efficiencies larger than 18% at pH = 14. Moreover, the STH efficiencies are larger than 18% even at all investigated pH values for Y2CHCl (18.5-22.6%), Y2 CFCl (∼18.7%), and Y2 C(OH)Cl (∼19.4%). Based on the first-principles calculations, we here for the first time propose an easy strategy to design Janus MXene photocatalyst candidates with possible high STH efficiency according to the electronic properties of their symmetric counterparts. Our study is helpful for the future design of Janus MXenes and more generally Janus 2D photocatalysts for water splitting with high STH efficiency.

Two-dimensional Janus XWZAZ' (X = S, Se, Te; A = Si, Ge; Z, Z' = N, P, As): candidates for photocatalytic water splitting and piezoelectric materials.

Due to their extraordinary properties, particularly the presence of an inherent electric field that effectively suppresses the recombination of photogenerated carriers, Janus two-dimensional (2D) materials exhibit strong light absorption and high solar-to-hydrogen conversion efficiency, making them promising candidates for photocatalytic water splitting applications. In this study, we conducted first-principles calculations to investigate the layers XWZAZ' (X = S, Se, Te; A = Si, Ge; Z, Z' = N, P, As; Z ≠ Z'). Out of 36 possible structures, 25 were found to be stable in terms of their dynamic, thermal, and mechanical properties. Among these 25 stable structures, 22 exhibit semiconductor behavior. Notably, 9 of these semiconductor structures demonstrate excellent photocatalytic and light absorption properties. These 9 photocatalysts possess remarkable light absorption rates (∼23%), high solar-to-hydrogen energy conversion efficiencies (38.447%), ultra-high carrier mobilities (101 596.37 cm2 s-1 V-1), and spontaneous hydrogen evolution reaction (HER) capabilities. Furthermore, all 22 semiconductor structures display significant piezoelectric responses both in-plane and out-of-plane, and biaxial strain has a considerable impact on the properties of the 25 stable structures. This study not only provides potential candidate materials for photocatalytic and piezoelectric applications but also offers theoretical guidance for addressing energy crises and environmental pollution challenges.

High-efficiency, thermal stable, and self-floating silver nanowires/Ti3C2Tx MXene/aramid nanofibers composite aerogel for photothermal water evaporation and antibacterial application

Interfacial solar steam generation shows great potential as a technology for seawater desalination. However, there are still considerable challenges in manufacturing photothermal evaporators with ultra-low thermal conductivity, mechanical robustness, and high-temperature resistance. Herein, we report Ag nanowires/Ti3C2Tx MXene/aramid nanofibers (Ag/Ti3C2Tx/ANFs) composite aerogel photothermal evaporators with internal three-dimensional (3D) micropores and a layered structure. The ANFs porous frame, with excellent mechanical properties and low thermal conductivity, allows abundant water transmission channels and reduces heat loss. Ti3C2Tx MXene and Ag NWs, known for their broadband absorption capability and antibacterial properties, enhance photothermal conversion efficiency. The Ag/Ti3C2Tx/ANFs composite aerogel distinguishes itself with a wide compression range (2 %∼60 %), remarkable light absorption capacity (96 %), and low thermal conductivity (0.49 W/mK), excellent thermal stability ensures the composite aerogel could withstand a wide temperature range from ∼500 °C to ∼196 °C. As expected, under one sun illumination, the Ag/Ti3C2Tx/ANFs composite aerogel presents a high evaporation rate of 2.21 kg m-2h−1 with an energy efficiency of 92 %. In addition, this evaporator composite aerogel exhibits outstanding and efficient salt tolerance, desalination, antibacterial properties, and heavy-metal ion wastewater purification capabilities. The unique evaporator structure presented here offers a new perspective for the structural design of next-generation, high-efficiency solar evaporators.

Z-scheme Bi2SiO5/Ni-doped Ag6Si2O7 heterojunction with remarkable photocatalytic performance for MO degradation with enhanced light absorption ability: Adjustment of electron transfer path and energy band structure

In this paper, a novel Bi2SiO5/Ni-Ag6Si2O7 semiconductor with remarkable light absorption ability and electron transfer efficiency was synthesized through ice bath deposition and hydrothermal method. The addition of Ni2+ reduced the particle size of Ag6Si2O7 and increased specific surface area. Under simulated sunlight, the degradation rate of the optimal samples for MO reached 0.03743 min−1, which was 7.28 times, 3.15 times and 1.56 times than that of Bi2SiO5 and Ag6Si2O7 and Bi2SiO5/Ag6Si2O7, respectively. The formation of Z-scheme heterojunction inhibited the photoinduced carrier recombination, promoted the generation of active free radicals and preserved high redox capacity of photogenerated carriers. According to the density functional theory (DFT) and M-S test, an intermediate doping energy level was introduced to Ag6Si2O7, which acted as the capture center of photogenerated carriers and effectively adjusted the energy band structure. The impurity energy level further inhibited the recombination of carriers and promoted the electron transfer in the Z-scheme transfer mechanism. Moreover, the introduction of Ni2+ further enhanced the light response of photocatalysts. Therefore, the improved photocatalytic ability was assigned to the introduction of Ni2+ ions based on the formation of heterojunction.

Highly stable, easily regenerable photothermal porous black ceramics used in an energy-efficient bionic system for practical solar-driven interfacial evaporation

Solar-driven interfacial evaporation has emerged as a promising way for renewable energy-driven clean water production, due to its ability to concentrate heat on the evaporation surface and facilitate the evaporation process. Nevertheless, the weak interaction between solar-absorbing materials and porous support substrates has posed a significant challenge in achieving the necessary combination of light absorption, mechanical strength, and long-term stability required for practical solar-driven water evaporation. In this work, we prepared porous black ceramics with both high light absorption and strong structural support, exhibiting a remarkable light absorption of 94% in the solar spectrum. Afterward, inspired by the water transport and evaporation process of mushrooms, we developed an energy-efficient bionic system. The resulting system demonstrates an evaporation rate of 1.41 kg/m2/h under 1 sun illumination (1 kW/m2) and 25 °C, attributable to the heat localization effect. Furthermore, under natural sunlight with an average solar intensity of 0.44 kW/m2, the bionic system exhibits an evaporation rate of 0.7 kg/m2/h. This work not only developed a highly stable, regenerable photothermal material and an energy-efficient bionic system for practical solar-driven water evaporation, but also highlights the immense potential of porous ceramics in advancing the field of solar-driven interfacial evaporation.

ZIF-67@MXene structure synergistically improve heat storage and photothermal conversion of phase change material

How to design and construct the MOF-based composite phase change materials (PCMs) with simultaneously enhanced heat storage and photothermal conversion to meet the performance requirement of solar energy utilization still remains a challenge. Herein, the polyethylene glycol was selected as PCM, the ZIF-67@MXene acted as supporting structure, a series of polyethylene glycol/ZIF-67@MXene form-stable composite PCMs (PZM fs-CPCMs) with improved latent heat and photothermal conversion were designed and prepared. All the PZM fs-CPCMs showed obvious heat storage and release characteristics, and their latent heat reached ∼106.01 J/g. Furtherly, the latent heat loss of PZM40 was only 1 % after 100 phase change cycles, indicating outstanding thermal reliability, which was closely related to the structure and morphology of the PZM fs-CPCMs. More importantly, during irradiation, the maximum surface temperature of PZM fs-CPCMs regularly increased (42.5–45.2 °C) with increasing ZIF-67@MXene content, while during cooling, it regularly decreased (27.4–23.2 °C). Based on the surface temperature distribution results, the photothermal conversion ability and heat transfer rate of PZM fs-CPCMs were effectively improved, which was mainly attributed to the remarkable light absorption and conversion ability and high thermal conductivity of MXene. Meanwhile, the PZM fs-CPCMs showed good chemical compatibility, crystallinity characteristic and thermal stability, which was conducive to the solar energy utilization.

Self-powered photodetectors with high detectivity based on MoSe2/Si heterojunction using ITO as the transparent electrode and highlight trapping structures

Due to the remarkable light absorption effect and electrical properties, transition metal dichalcogenide-based heterojunction allows for the realization of a highly sensitive photodetector. A self-powered photodetector with high detectivity (355–980 nm) was reported based on the MoSe2 that was prepared by the MoO3 films as the precursor layer which reduced the reaction temperature. The n-type silicon substrates with optical trapping structures were prepared by wet chemistry, which can enhance the performance of photodetectors. The as-grown MoSe2 nanosheet was applied in the self-powered ITO/MoSe2/Si photodetector. The self-powered device can detect faint light with a power density below 200 μW/cm2 which shows high responsivity (18.13 mA/W), normalized detectivity (2.80 × 1012 cm·HZ1/2W−1) and a fast response time of 43 ms under 980 nm (1.5 mW/cm2) illumination at zero bias. The ITO/MoSe2/ Si heterojunction with outstanding properties has promising potential for application in self-powered, sensitive, and broadband photodetectors.

3D-printed graphene-anatase TiO2 photoanode with well-interconnected hierarchical channels for integrated self-floating photofuel cell powered by seawater pollutants

Photoelectrode architecture with well-interconnected oriented micro- and nanochannels is essential and critical for photofuel cell (PFC) to high-performance energy conversion of pollutants. However, challenges remain pertaining to manufacturing consistency and scalability, high efficiency in pollutant trapping and remarkable light absorption. Herein, a novel photoelectrode featuring porous microlattice structure was constructed via a scalable and controllable extrusion-based 3D printing strategy, with well-interconnected oriented channels as well as enriched hierarchical and open pores built by jointing tortuous photoactive graphene sheets. The unique architectural features facilitated high light absorption, and meanwhile guaranteed unimpeded channels acting as “superhighways” for rapid seawater pollutant diffusion and trapping. An integrated PFC assembled with 3D-printed photoelectrode demonstrated impressive photoelectric conversion capability for seawater pollutants under persistent self-floating and sunlight, with exceptional cycling stability and maximum power density of 0.09 mW cm−2. This work has shed light on new strategies for fabricating rational photoelectrode architectures toward high-performance PFC devices.

Tailoring the π-system of benzimidazole ligands towards stable light-harvesting cyclometalated iridium(III) complexes.

The synthesis, structure, optical and redox properties as well as photovoltaic studies of iridium(III) complexes with cyclometalated 2-arylbenzimidazoles decorated with various polyaromatic fragments and an ancillary aromatic β-diketone are reported. Despite the strong preference of the iridium(III) ion to form bis- or tris-cyclometalated complexes in which the metal participates in five-membered metallacycles, the cyclometalation of the benzimidazole ligands containing rigid π-extended systems yields dimeric complexes containing strained five- or six-membered metallacycles and allows for generating an extremely rare monocyclometalated complex. X-ray crystallography shows that the steric strain observed in the dimers is retained in heteroleptic diketonate complexes which is also corroborated by gas-phase DFT calculations. While emission maxima and redox potentials of the heteroleptic complexes exhibit just a moderate variation upon the change of the cyclometalated ligands, the extension of the π-system of the benzimidazole ligands give the complexes remarkable light absorption in the visible spectral range, which meets the requirements for application in dye-sensitized solar cells. At the titania photoanodes, these iridium dyes retain their optical properties and exhibit power conversion efficiencies under standard AM 1.5 G conditions comparable to those of other iridium-based sensitizers. These results demonstrate that the size and position of the π-extended fragment in cyclometalated ligands can modulate not only the electronic structure of the corresponding iridium(III) complexes, but also affect their composition, structure and reactivity that may find implications in future design of emerging iridium dyes, emitters and catalysts.

Construction of benzothiadiazole-based D-A covalent organic frameworks for photocatalytic reduction of Cr (VI) and synergistic elimination of organic pollutants

Covalent organic frameworks (COFs) are porous crystalline materials that have attracted considerable attention owing to their environmental-friendly photocatalytic characteristics. However, insufficient charge transfer and rapid charge recombination occur in the sunlight-driven photocatalytic performance of most COFs, which greatly impedes their photocatalytic activity. In this study, a donor-acceptor (D-A) COF, DTB-BT-COF, was synthesized using electron-deficient 4,4'-(benzo[c] [1,2,5]thiadiazole-4,7-diyl)dianiline (BT) and electron-rich 1,3-dihydroxy-2,4,6-trialdehyde benzene (DTB). With its D-A structure, DTB-BT-COF exhibited outstanding photocatalytic performance for Cr(VI) reduction, which can be attributed to the integrative effect of the remarkable light absorption ability and more efficient separation of the photogenerated charge carriers. More significantly, DTB-BT-COF has proven to be a highly efficient photocatalyst in the removal of different aqueous contaminants with rhodamine B, methylene blue, or metronidazole as scavengers, which could be attributed to the synergetic effect between photocatalytic oxidation and reduction by individually consuming photogenerated holes and electrons. This study provided a new way to construct highly efficient D-A COFs for the purification of wastewaters containing mixed heavy metal ions and organic pollutants.

Template-free preparation of carbon nitride hollow spheres with adjustable sizes for photocatalytic hydrogen generation

Carbon nitride hollow spheres (CNHS) with adjustable sizes were successfully fabricated via a template-free supramolecular pre-assembly strategy, in which melamine-cyanuric acid (MCA) hollow spheres were constructed through hydrogen bonds. A feasible formation mechanism was proposed, which coupled an inside-out Ostwald ripening with the supramolecular pre-assembly process. Interestingly, the sizes of MCA could be manipulated by changing the pre-assembly temperature. Consequently, the sizes of CNHS were adjustable. The optimal CNHS exhibited excellent photocatalytic hydrogen evolution rate (98.6 μmol/h) in the visible-light region, which was approximately 11 times higher than that of bulk carbon nitride calcined by melamine. The significantly improved performance was due to the contributions including: the unique architectures with remarkable light absorption ability, high electrical conductivity, relatively narrowed band gap, fast charge separation. This work provides a facile template-free supramolecular pre-assembly strategy to fabricate carbon nitride hollow spheres with adjustable sizes for the first time.

Electrically Conductive, Optically Responsive, and Highly Orientated Ti3C2Tx MXene Aerogel Fibers

AbstractAerogel fibers, which combine the lightweight and multimesoporous properties of aerogel with the flexible and slender characteristics of the fiber, have received growing attention in the fields of smart fabrics, flexible electronic devices, and transparency‐determined optics. Herein a pure Ti3C2Tx MXene aerogel fiber, showing an intriguing oriented mesoporous structure, ultrahigh electrical conductivity, and electrothermal/photothermal dual‐responsiveness, is fabricated via a simple dynamic sol–gel spinning and subsequent supercritical CO2 drying. MXene aerogel fibers exhibit tunable porosity (96.5–99.3%), high specific surface area (up to 142 m2 g−1), and low density (down to 0.035 g cm−3). Benefiting from the metal‐like conductive MXene nanosheets and their high orientation induced by dynamic sol–gel wet spinning, the resultant Ti3C2Tx MXene aerogel fibers display ultrahigh conductivity up to 104 S m−1, which far surpasses the known aerogel materials (including aerogel monoliths, aerogel fibers, and aerogel films) reported in the literature. In addition, MXene aerogel fibers also have excellent electrothermal/photothermal dual‐responsiveness due to high electrical conductivity and remarkable light absorption ability. The combination of these characteristics makes MXene aerogel fibers with encouraging potential in flexible wearable devices, smart fabrics, and portable equipment applications.

Comparisons of visible-light driven photocatalytic CO2 conversion performances over mesoporous CdSxSe1–x with different molecular compositions

This study presents a synthesis method for nanowire arrayed mesoporous CdSxSe1-x compounds with different S/Se molar ratios. Both ternary and binary compound semiconductors are synthesized by hard-templating using SBA-15 as a silica template. The synthesized mesoporous materials have high specific surface areas of approximately 65–100 m2 g−1 and remarkable light absorption properties in the UV to visible light region (1.7–2.4 eV), and thus they are appropriate for the photo-conversion of CO2 into CO and CH4. The results show that the compositions of CdSxSe1-x excellently agree with the compositions of the reactants. Moreover, the band gaps of the mesoporous CdSxSe1-x samples could be directly tuned by varying the composition of the reactants. It is concluded that mesoporous CdSe achieves the highest CH4 yield rate, i.e., 0.382 μmol gcat–1 h–1, and CdS0.5Se0.5 achieves the highest CO yield rate (among all the samples synthesized), i.e., 5.633 μmol gcat–1 h–1. Also, it is found that the CO2 photoconversion performance on mesoporous II-VI photocatalyst are highly affected by CO2 adsorption capacities and photo-generated charge separation.

Tapered Coaxial Arrays for Photon- and Plasmon-Enhanced Light Harvesting in Perovskite Solar Cells: A Theoretical Investigation Using the Finite Element Method.

Although there have been reports of separate studies of photon-enhanced and plasmon-enhanced light harvesting to improve perovskite solar cell (PSC) efficiency, there are none that have achieved simultaneous enhancement in both photonic and plasmonic effects in PSCs. In this work, we designed a layer of tapered coaxial humps (TCHs) to harvest both in PSCs. The light absorption behavior of the textured perovskite layer in PSCs was systematically investigated through the finite element method (FEM). The calculation results show that the TCH-textured perovskite layer absorbs 67.6 % of visible light under AM 1.5G solar irradiation, a 21.8 % increase relative to the planar reference cell without TCHs. Using this design, a perovskite thickness of only 106 nm is needed to realize the full light absorption that normally requires 300-nm-thick perovskite without TCHs. To reveal the mechanism of light absorption enhancement, the specific field distributions were studied. We demonstrated that different photonic modes and plasmonic modes collectively result in remarkable light absorption enhancement in the 500-800 nm wavelength range. The textured PSCs reported herein provide an effective method to decrease Pb-based perovskite consumption and realize angle-insensitive and ultrathin PSCs.

Lead-free and electron transport layer-free perovskite yarns: Designed for knitted solar fabrics

Highly flexible and Lead-free perovskite solar yarns, based on methylammonium tin mixed halide- Polyvinylpyrrolidone (PVP) composite nanofibers doped with [6,6]-Phenyl C61 butyric acid methyl ester (PC61BM), as the light harvesters are reported. The photoactive nanofiber layer of the solar yarn featured an optical bandgap of 1.65 eV, with a remarkable light absorption capacity > 90% in the wavelength range of 300–550 nm, outstanding flexibility, and an impressive charge carrier lifetime of 278 ns which rises to 300 ns upon doping with PC61BM. These photoactive nanofibers are directly electrospun on top of poly(3-hexylthiophene-2,5-diyl) ‘P3HT’, as the hole transporting layer, which was coated on a multi-filament carbon fiber yarn. The resulting yarn is twisted with a commercial silver yarn, serving as the positive electrode. The ensuing fiber-shaped solar device exhibits a maximum power conversion efficiency of 5.34% which is increased to 7.49% upon doping the photoactive layer with 0.17% PC61BM. A knitted solar fabric from the novel solar yarn with 45-mm × 35-mm active area presented a maximum power density of 1.21 mWcm−2 under 1 sun (1000 Wm−2) solar illumination.