Broad Absorption Research Articles

Frequency selective rasorber based on cross bend resonators for wideband transmission and absorption

The wideband absorption and transmission of frequency-selective rasorber (FSR) remain a persistent challenge in the application of radar devices. In this article, a novel high performance wideband FSR design based on cross bend resonators was proposed. The FSR consists of an upper absorption lossy layer, which offers broad absorption and transmission bands, and a lower bandpass frequency-selective surface that enables a highly selective transmission of incident electromagnetic wave. Full wave simulation results showed that this novel design achieves an absorption bandwidth of 83.7% with more than 90% absorptivity in the frequency range of 5.2–12.7 GHz. Furthermore, the passband’s fractional bandwidth for the insertion loss (IL) less than −3 dB is 33.9%, ranging from 14.9 to 21 GHz, with the minimum IL recorded at 0.69 dB at 17.7 GHz. To further verify the proposed method, a prototype FSR with 10 × 10 units of 120 mm × 120 mm was fabricated and the performance of the FSR was tested. The experiment results were in good agreement with the simulated results, and it showed a significant monostatic radar cross-section reduction in the frequency range of 5.3 GHz to 18.3 GHz compared with a metallic plane of the same size.

Structure and gamma attenuation behavior of copper ions in host glass from the system (P2O5–LiF–CaF2)

Copper-doped lithium calcium fluorophosphate glasses in the compositional system (60−x)P2O5·20LiF·20CaF2·xCuO (x = 0−3 mol%) were prepared using the conventional melt quenching technique. X-ray diffraction confirmed the amorphous, non-crystalline phase of the glasses. Optical absorption spectra indicated the presence of additional broad visible-NIR absorption bands upon CuO doping, attributed to distorted Cu2+ ions. Possible overlaps from Jahn-Teller distorted sites or clustering into nanodomains may contribute to band broadening. The direct optical bandgap was found to reduce from 3.89 eV to 1.17 eV with increasing CuO content. The study of physical parameters showed almost linear variation in density (2.62–2.95 g/cm3) and molar volume (40.45–35.29 cm3/mol) with incremental CuO substitution, explained by changes in structural packing efficiency and formation of Cu–O complexes. FTIR spectra revealed vibrations corresponding to phosphate structural groups. The simulation of radiation shielding parameters displayed steady improvements with higher CuO fractions, which were related to enhanced photon interactions via photoelectric absorption and Compton scattering.

Improved near-resonant two photon absorption of α-MnO2 nanowires surface functionalized reduced graphene oxide sheets

The versatile study of graphene derivatives has resurgence of interest on understanding its nonlinear optical response at different nanoscales. Nanostructured manganese dioxide: reduced graphene oxide (MnO2: rGO) hybrids were synthesized by reduction method by varying the content of rGO (5, 10, 15 & 20 wt%). X-ray Photoelectron Spectroscopy studies confirmed the surface functionalization of MnO2 on rGO. Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Tunnelling Electron Microscopy (HRTEM) witness that with respect to the content of rGO, the morphology of MnO2 varies radically from clusters to nanorods to nanowires over the surface of rGO sheets. Ground state absorption spectra of the hybrids have absorption edge at 268 nm corresponding to combined metal oxide charge transfer between rGO (π-π* transition of CC and n-π transition of C-O bonds) and MnO2 (d-d transition). Moreover, hierarchical MnO2 nanowire network resided on 2D rGO sheets involves broad absorption at the visible spectral domain due to polaron transition as well the localization of π- π* transited electrons that facilitates the probability of occurrence of excited state absorption. Intensity dependent open aperture Z-scan technique of the prepared hybrids using Q-switched Nd: YAG 532 nm nanopulsed laser reveals unusual transitions and enhanced nonlinear absorption. MnO2:(5 wt%) rGO shows saturable absorption (SA) at low intensity and changeover dynamically to reverse saturable absorption (RSA) at higher intensity. MnO2:(10 & 15 wt%) rGO exposes coupled nonlinear absorption (SA + RSA) owing to the combined effect of graphene (π-states) and MnO2 (σ-states). MnO2:(20 wt%) rGO exhibits a stronger RSA ascribed to sequential two photon absorption. The third-order nonlinear absorption coefficient and limiting threshold of MnO2: rGO (20 wt%) are 4.04 ×10-10 m/W and 0.84 ×1012 W/m2, which shows five-fold increase compared to bare rGO and MnO2. The obtained results propose that the optical nonlinearity of MnO2 nanowires surface functionalized rGO sheets can significantly be tuned to meet the requirements for fabricating laser safety devices.

Rational Bi[sbnd]Mo[sbnd]O nanospheres decorated g-C3N4 for photocatalytic performance of dye degradation

Developing a superior heterostructured composite, optimizing performance through synergies from complementary advantages in diverse materials, remains an ongoing challenge. The rise in organic contaminants in freshwater bodies possesses a major threat to human health. Various dyes such as Rhodamine B, Eosin Y and Methylene Blue are found in excess concentration due to industrial usage and their removal is important for environmental remediation and contaminant-free water. In this study, we report synthesis and fabrication of Bi2MoO6/g-C3N4 (BM/CN) composite photocatalyst and Rhodamine B photodegradation studies. The composite photocatalysts have been characterized using XRD, TGA, FT-IR, UV–Vis, TRPL, SEM, TEM, XPS, electrochemical, and BET studies over g-C3N4, Bi2MoO6, and Bi2MoO6 (10–40 wt%) supported on g-C3N4 photocatalysts. The photocatalytic studies are performed using various composite photocatalysts of BM/CN show 30%-Bi2MoO6 supported on g-C3N4 (30BM/CN) exhibits maximum visible light activation for dye degradation with 3.6 and 2.4-fold higher rate of degradation than bare g-C3N4 and Bi2MoO6, respectively. Higher surface area, broad light absorption, enhanced lifetime, lower charge transfer and higher transient photocurrents of the composite photocatalysts compared to g-C3N4 and Bi2MoO6. Moreover, study is aided with scavenger tests to support the proposed mechanism.The increased photoactivity of 30BM/CN is due to the synergistic interplay of improved charge generation and a reduction in the electron-hole (e−/h+) recombination rate.

Unveiling the Role of BODIPY Dyes as Small‐Molecule Hole Transport Material in Inverted Planar Perovskite Solar Cells

Perovskite solar cells (PSCs) have become a research hotspot since their dramatic increase in power conversion efficiency (PCE), surpassing 26% due to advances in cell engineering and interfacial layers. Within the last factor, hole transporting materials play a crucial role in enhancing device performance and stability. Among several molecular building blocks, BODIPYs are attractive for the design of novel hole transporting material (HTMs) due to their outstanding photophysical and charge transport properties easily tuned by synthetic modifications. Herein, the synthesis of five new BODIPY‐based HTMs PyBDP 1–5 are reported, functionalized at the meso‐ and α‐ positions with pyrenyl and arylamino units, respectively. The resulting compounds exhibit broad absorption in the visible region, remarkable thermal stability, narrow bandgaps, suitable energy levels, and good hole extraction capability, as subtracted from experimental and computational characterizations. The performance of the BODIPY derivatives as HTMs is evaluated in planar inverted (p‐i‐n) PSCs and compared to commonly used PTAA, resulting in highly efficient systems, reaching PCEs very close to that obtained with the reference polymer (21.51%). The incorporation of these BODIPY‐based HTMs result in an outstanding PCE of 20.37% for devices including PyBDP‐1 and 19.97% for devises containing PyBDP‐3, thus demonstrating that BODIPY derivatives are a promising alternative to obtain simple and efficient organic HTMs.

Fabrication, characterization, spectroscopic, and magnetic properties of polyaniline/magnetite (PANi/Fe3O4) nanocomposites

In this research, pure polyaniline (PANi), pure magnetite (Fe3O4), and then PANi/ Fe3O4 nanocomposites were prepared and characterized. FT-IR spectra of the prepared samples indicate successful polymerization of PANi onto Fe3O4. PANi/Fe3O4 nanocomposites exhibit broad absorption bands at specific wavenumbers, indicating the presence of various functional groups. The observed blue shift in certain peaks suggests the interaction between nitrogen atoms and oxygen atoms on the magnetite surface through hydrogen bonding. The intensity and wavenumber of the Fe3O4 band decrease, indicating weakened Fe–O bonds. These findings demonstrate a strong interaction and combination between PANi and Fe3O4 in the nanocomposites. Fe3O4 nanoparticles exhibit a regular spherical shape with an average diameter of 16 nm. However, they also show non-uniform size distribution due to aggregation into larger secondary particles, likely driven by attractive forces. PANi/Fe3O4 core-shell nanocomposites demonstrate clear morphological changes, with Fe3O4 nanoparticles well spread and wrapped by the PANi shell. The electron diffraction technique confirms the crystalline structure of Fe3O4 nanoparticles, showing diffraction rings consistent with magnetite. The results confirm the potential of incorporating magnetic Fe3O4 nanoparticles to impart magnetic functionality in the resulting PANi-based nanocomposite materials. Magnetic saturation measurements displayed an enhancement in magnetization with increasing Fe3O4 nanoparticles. The change in magnetic behavior for doped samples provides a means of tuning the magnetization strength of the composites to meet the application requirement such as data storage and magnetic sensors.

Polarized spectroscopic properties of Tm3+/Ho3+:YPO4 single crystal: A potential gain medium for tunable and ultrafast pulse laser at 2.0 μm

YPO4 crystals co-doped with Tm3+ and Ho3+ ions (Tm3+/Ho3+:YPO4) have been prepared using the high temperature solution method. The crystal structure, electronic band and polarized spectroscopy were characterized. It has intense and broad absorption bands around 800 nm with a full width at half maximum of 14.31 nm and 22.95 nm for π- and σ-polarizations, respectively. Based on Judd-Ofelt theory, relevant parameters about the radiative properties were systematically analyzed. The broad emission bands of Tm3+ and Ho3+ from 1600 to 2300 nm allow wide tunability of laser oscillation. The energy transfer efficiency from Tm3+: 3F4 to Ho3+: 5I7 level in YPO4 crystal was calculated to be 54.59 %. The results show that Tm3+/Ho3+:YPO4 is expected to be applied in tunable and ultrafast pulse laser at 2.0 μm.

Multi-Functional 2D Covalent Organic Frameworks with Diketopyrrolopyrrole as Electron Acceptor.

2D covalent organic framework (COF) materials with extended conjugated structure and periodic columnar π-arrays exhibit promising applications in organic optoelectronics. However, there is a scarcity of reports on optoelectronic COFs, mainly due to the lack of suitable π-skeletons. Here, two multi-functional optoelectronic 2D COFs DPP-TPP-COF and DPP-TBB-COF are constructed with diketopyrrolopyrrole as electron acceptor (A), and 1,3,6,8-tetraphenylpyrene and 1,3,5-triphenylbenzene as electron donor (D) through imine bonds. Both 2D COFs showed good crystallinities and AA stacking with a rhombic framework for DPP-TPP-COF and hexagonal one for DPP-TBB-COF, respectively. The electron D-A and ordered intermolecular packing structures endow the COFs with broad UV-vis absorptions and narrow bandgaps along with suitable HOMO/LUMO energy levels, resulting in multi-functional optoelectronic properties, including photothermal conversion, supercapacitor property, and ambipolar semiconducting behavior. Among them, DPP-TPP-COF exhibits a high photothermal conversion efficiency of 47% under 660nm laser irradiation, while DPP-TBB-COF exhibits superior specific capacitance of 384Fg-1. Moreover, P-type doping and N-type doping are achieved by iodine and tetrakis(dimethylamino)ethylene on a single host COF, resulting in ambipolar semiconducting behavior. These results provide a paradigm for the application of multi-functional optoelectronic COF materials.

Boosting the Photocatalytic Performance of g-C3N4 through MoS2 Nanotubes with the Cavity Enhancement Effect.

The development of catalysts with high photon utilization efficiency is crucial for enhancing the catalytic performance of photocatalysts. Graphitic carbon nitride (g-C3N4) is a prominent material in the field of photocatalysis. However, it still exhibits drawbacks such as low utilization of visible light and severe recombination of photogenerated carriers. To address these issues, this study employs MoS2 nanotubes (NTs) as cocatalysts and constructs MoS2 NTs/g-C3N4. The MoS2 NTs/g-C3N4 exhibits a significant cavity enhancement effect through multiple light reflections. This results in a broad spectral absorption range and high photon utilization efficiency, while also reducing the recombination of photogenerated carriers. The photocatalyst demonstrates outstanding performance in both photocatalytic hydrogen production and photodegradation of organic pollutants. Specifically, the hydrogen production rate is 1921 μmol·g-1·h-1, which is approximately 2.4 times that of g-C3N4. Furthermore, the photodegradation rate of Rhodamine B reaches 98.6% within 30 min, which is approximately three times higher than that of g-C3N4. Free radical capture experiments confirm that holes (h+) are the primary active species in photodegradation. A plausible photocatalytic mechanism for the catalyst is proposed. This study provides valuable insights into the development of heterojunction photocatalysts with high photon utilization efficiency.

Micro-helical Ni3Fe chain encapsulated in ultralight MXene/C aerogel to realize multi-functionality: Radar stealth, thermal insulation, fire resistance, and mechanical properties

Magnetic carbon aerogels with high porosity, ultralow density, and excellent impedance matching are considered to be a promising microwave absorption (MA) material. In this study, ethylene glycol polymerization is used to assemble Ni3Fe particles into a micro-helical chain, which is further wrapped by MXene and then encapsulated in poly-Schiff-base aerogels through the carbonyl–amine condensation reaction. Finally, ultralight TiO2/Ni3Fe/MXene/C (NFMC) aerogels are synthesized through calcination treatment. Benefiting from the electromagnetic synergistic effect of multi-dimensional and multi-component materials, the NFMC-7 aerogel exhibits excellent MA performance with a minimum reflection loss of −61.6 dB at 3.0-mm thickness and an effective absorption bandwidth of 8.16 GHz at 2.77-mm thickness under a low filler loading of 7.6 wt%. Commercial computer simulation technology is used to verify the strong magnetic and dielectric loss characteristics of Ni3Fe chains. At the same time, the NFMC-7 aerogel exhibits excellent radar stealth, heat insulation, compression resistance, and fire resistance performance, which verifies its practical applicability. Overall, this work establishes an effective strategy to fabricate multi-functional magnetic aerogels, which can serve as lightweight, thin, and strong microwave absorbers with broad absorption bandwidth.

Efficient identification of broad absorption line quasars using dimensionality reduction and machine learning

Efficient identification of broad absorption line quasars using dimensionality reduction and machine learning

Ultra-wideband electromagnetic wave absorption property with bimetallic Co6W6C/carbon

Binary dielectric materials, particularly carbide/carbon composites, have garnered considerable attention for their promising electromagnetic wave (EMW) absorption property. In this work, bimetallic carbide and carbon composite (Co6W6C/C) was successfully prepared through hydrothermal method and pyrolysis process. Characterization results reveal the growth of Co6W6C nanoparticles on two-dimensional carbon nanosheets. The mass ratio of glucose (C6H12O6) to Co6W6C was found to significantly impact the EMW absorption performance. When 150 mg C6H12O6 and 100 mg CoWO4 were added, the CWCC-2 composite exhibited an ultra-high effective absorption bandwidth of 7.49 GHz (10.51–18 GHz). In the far-domain circumstance, the highest radar cross-section acreage reached 21.24 dB m2. The exceptional EMW absorption performance can be attributed to the synergistic effects of impedance matching, electrical losses, and magnetic losses. The Co6W6C/carbon composite, synthesized through a facile approach, showcases a broad electromagnetic wave absorption bandwidth, paving the way for a breakthrough in materials science with wide-band and high-efficiency absorption capabilities.

Optical properties and passive self Q-switching of floating zone grown Cr–Nd co-doped YVO4 crystal

Single crystals of Cr (0.7, 1.0, 1.4 and 2.0 at%) and Nd (0.7 at%) co-doped yttrium vanadate (YVO4) were grown by optical floating zone method. [100]-oriented elements were fabricated from the grown crystals for optical and lasing studies. The refractive index analysis revealed that the values of ordinary refractive indices (no) for 0.7, 1.0, 1.4 and 2.0 at% Cr doped samples were found to be almost constant except for a slight increase corresponding to 532 nm. But the extraordinary refractive indices (ne) was found to increase with Cr doping concentration and it is maximum at 1.4 at% for all the wavelengths. The thermal coefficient of ne and no increases slightly and becomes constant beynd 1.4 at% of Cr. The band gap of the crystal is polarization sensitive with the values in the range of 3.51–3.55 eV and 3.59–3.62 eV for electric field parallel and perpendicular to c axis, respectively. The band gap does not exhibit any significant change on Cr doping. The emission spectrum with excitation at 808 nm is characterized by three broad asymmetric bands centered at 896, 1064 and 1341 nm. The emission intensity for the peak around 1064 nm decreases with an increase in Cr due to a broad absorption around 1100 nm of Cr5+ ion and, therefore, this band is exploited for passive Q-switching in the crystal. Further, excitation at 400 nm of Cr band revealed that there is strong emission at 1064 nm, which may be explored for pumping the gain medium with solar radiation. Finally, a stable passive Q-switching at 1064 nm was demonstrated in [100] element fabricated from the gown crystal having 1.4 at% Cr. An output power of ∼108 mW having pulse-width ∼220 ns and repetition rate ∼239 kHz was achieved for a pumping of ∼14.6 W at 808 nm.

Reinforcement of microwave absorption and thermal conductivity of polydimethylsiloxane achieved by metal-organic framework-derived carbon nanotube/boron nitride flake heterogeneous structure

Due to the rapid advancement of electronic devices towards miniaturization, high-integration, multi-functionality, high-power, and high-frequency, it is necessary to design thermal interface materials (TIMs) that possess exceptional thermal conductivity as well as good capabilities for absorbing electromagnetic waves. In this report, carbon nanotubes (CNTs) containing cobalt (Co) nanoparticles have been in-situ grown on the surfaces of boron nitride flakes (BNFs) using the Co nanoparticles as catalysts which formed by the high-temperature pyrolysis and reduction of zeolite-imidazolate skeleton. Then, a multifunctional heterogeneous structure of Co@CNT/BNFs has been developed with tunable microwave absorption (MA) property and high thermal conductivity, which can be applied to enhance the MA performance and thermal conductivity of polymers simultaneously. The minimum reflection loss can reach −46.6 dB and a broad absorption bandwidth of 5.92 GHz can be obtained when adjusting the content of Co@CNT/BNFs in the absorbers. Furthermore, the thermal conductivity of the polydimethylsiloxane measured using the transient hot-wire apparatus is 0.72 W/(m·K) when the content of Co@CNT/BNFs is 30 wt%, exhibiting excellent heat dissipation performance in thermal management. This work is significant for investigating MA packaging and high thermally conductive TIMs for the electronic devices.

Visible-light harvesting SrTiO3 solid solutions for photocatalytic hydrogen evolution from water.

The fabrication of solid solutions represents a compelling approach to modulating the physicochemical properties of materials. In this study, we achieved the successful synthesis of solid solutions comprising SrTiO3 and SrTaO2N (denoted as (SrTiO3)1-x-(SrTaO2N)x, 0 ≤ x ≤ 1) using the magnesium powder-assisted nitridation method. The absorption edge of (SrTiO3)1-x-(SrTaO2N)x is tunable from 500 to 600 nm. The conduction band minimum (CBM) of (SrTiO3)1-x-(SrTaO2N)x comprises the Ti 3d orbitals and the Ta 5d orbitals, while the valence band maximum (VBM) consists of the O 2p and N 2p orbitals. The microstructure of the (SrTiO3)1-x‑(SrTaO2N)x consists of small nanoparticles, exhibiting a larger specific surface area than the parent compounds of SrTiO3 and SrTaO2N. In the photocatalytic hydrogen evolution reaction (HER) with sacrificial reagents, the activity of solid solutions is notably superior to that of nitrogen-doped SrTiO3 and SrTaO2N. This superiority is mainly attributed to its broad light absorption range and high charge separation efficiency, which indicates its potential as a promising photocatalytic material. Moreover, the magnesium powder-assisted nitridation method exhibits obvious advantages for the synthesis of oxynitrides and bears instructional significance for the synthesis of other nitrogen-containing compounds and even sulfur-containing compounds.

Surfactant-induced morphology engineering in chitosan-derived carbon aerogels realizing high-efficiency absorption of electromagnetic wave

Despite the significant research advances in dielectric loss-type absorbents, developing high-efficiency electromagnetic wave (EMW) absorbents dominated by the conduction loss are still challenging due to the imbalance between impedance matching and conduction loss. In this study, for the first time, high-efficiency EMW absorption governed by the conduction loss in chitosan-derived carbon aerogels was realized through surfactant-assisted morphology modification. Electrostatic interaction and hydrogen bonding between chitosan and surfactants were ingeniously applied to induce tightly-stacked nanosheets to transform into three-dimensional (3D) interwork structure and loosely-stacked porous nanosheets, respectively, and thus the moderately enhanced conductivity converted the original EMW-transparent carbon to EMW-absorbing carbon. Benefiting from the favorable balance of impedance matching and conduction loss, the carbon aerogels with 3D interwork structure showed a broad effective absorption bandwidth (EAB) of 7.2 GHz (2.8 mm) and minimum reflection loss (RLmin) of −42.6 dB; and moreover, an ultra-wide EAB of 7.84 GHz at 2.9 mm occurred in the samples with loosen and wrinkled nanosheet structure, both outperforming most of reported carbon-based composite aerogels. This work provides a new insight for the morphology regulation and performance optimization of carbonaceous EMW absorbents.

Hollow carbon microsphere embedded with Fe nanoparticles for broadband microwave absorption

Nowadays, Fe-based microwave absorption materials still face crucial problems of poor oxidation resistance, lack of dielectric loss and narrow effective absorption bandwidth. In this work, we developed a feasible way of calcining and etching SiO2 microspheres coated Fe3+ and polydopamine (SiO2@Fe3+-PDA) to confine Fe nanoparticles (12 nm) in the hollow carbon microspheres with a thickness of 17 nm, which provides more interfaces and polarization sites to enhance microwave attenuation. With the increase of Fe content, the microwave absorption performance of the sample is gradually improved. When Fe content is 19.7 wt%, the sample has a minimum reflection loss (RL) of −30.9 dB and a broadband absorption bandwidth (RL ≤ −10 dB) of 11.9 GHz (6.1–18 GHz) at the thickness of 4.0 mm. The ultra-wide effective absorption bandwidth is ascribed to synergetic effect of Fe nanoparticles and carbon layer, which provide magnetic loss and dielectric loss, respectively. Moreover, the hollow structure extends the transmission path and induces the multiple scattering of the incident electromagnetic waves. The novel hollow Fe/C microspheres are promising as high-efficiency microwave absorbers with strong microwave absorption and broad absorption bandwidth.

DFT+U investigation of electronic, optical, and thermoelectric properties of YAuX (X=Si or Ge or Sn) half-Heusler alloys

Half-heusler alloys are fascinating thermoelectric materials because they have superior mechanical and transport properties. In this study, we used dft+u calculations and the Boltztrap equation to examine the electronic, optical, and thermoelectric properties of YAuSi, YAuGe, and YAuSn half-heusler alloys. The DFT+U approach predicted band gaps of 1.2767 eV, 0.611 eV, and 1.5741 eV for YAuGe, YAUSn, and YAuSi, respectively. We also observed that all materials under consideration have a broad absorption spectrum ranging from 1 eV to 12 eV, with notable peaks in the visible and UV ranges. The obtained opto-electronic properties position the three alloys as promising candidates for photovoltaic applications. Finally, thermoelectric property calculations revealed that the figure of merit values for YAuSi, YAuGe, and YAuSn HH alloys were 0.730, 0.726, and 0.736 at 800 K, respectively suggesting the materials are also suitable candidates for application in the field of thermoelectricity

Constructing multiple heterogeneous interfaces in one-dimensional carbon fiber materials for superior electromagnetic wave absorption

Due to impedance mismatch and a single loss mechanism, carbon fiber fails to meet the requirements for efficient absorbers in terms of lightweight construction and broad absorption band. In this study, we have successfully prepared one-dimensional beaded SiO2@SiC@C nanofiber (SSCF) composites with multiple heterogeneous interfaces by employing the electrospinning-carbothermal reduction method. The beaded SSCF composites effectively address the impedance mismatch issue by controlling silicon dioxide and silicon carbide through carbothermal reduction. This optimization enriches the defects and interfaces of carbon fibers composites, consequently enhancing the electromagnetic wave absorption performance. The SSCF composites demonstrate remarkable performance, with a minimum reflection loss of −59.53 dB at a matched thickness of 2.21 mm and a maximum absorption bandwidth of 6 GHz. This outstanding performance is attributed to the synergistic effects of the multi-phase composition, bead structure, and one-dimensional network structure. These features not only optimize impedance matching but also enhance defect loss, interface polarization loss (SiC/SiO2, C/SiO2, SiC/C, C/Air), conduction loss, and relaxation loss of the SSCF composites. Furthermore, radar cross-section analysis utilizing computer simulation technology confirms the excellent attenuation of microwave energy by the SSCF composites under realistic far-field conditions. This study provides valuable insights for designing efficient one-dimensional carbon-based electromagnetic wave absorbers.

Designing of phenothiazine dioxide based donor molecules with improved photovoltaic parameters for efficient perovskite solar cells

Perovskite solar cells are the emerging photovoltaics devices due to their high efficiency because of broad range light absorption and better charge carrier and separation properties. However, in the past few decades their material degradation and instability in the device operation accompanying low power conversion efficiency were the major drawbacks. To address these shortcomings, here we designed five Phenothiazine based novel hole-transporting molecules of d-Pi-A type with improved photovoltaic parameters for efficient perovskite solar devices. Detailed DFT calculation analysis with MPW1PW91 functions and 6–31 G basis set were performed for all molecules. Structural geometrical analysis along with density of states and transition density matrix analysis were extensively performed. Their electronic properties including HOMO and LUMO energies including energy gap, electron affinity, and ionization potential were also explored to elucidate the charge transfer characteristics. The lower values of reorganization in relation to reference molecules show that all designed molecules are better hole-transporters for perovskite building blocks. Lastly the devices photovoltaic parameter calculations for all the designed systems revealed that their Fill factor (FF), VOC and resultant power conversion efficiencies were significantly improved (18.63–22.81 % than its reference counterpart with PCE of 16.7 %) demonstrating their great potential for the future efficient PSCs devices.