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The current study presents six D-π-A configured non-fullerene acceptor chromophores (BTI1-BTI6) derived from benzotriindole compound end-capped with hexyldicyanovinyl groups, referred to as BTI (2 T-DCV-Hex)3, through structural tailoring of different terminal acceptors. Optoelectronic characteristics of newly designed chromophores were determined via DFT study at B3LYP/6-31G (d,p) functional. Various analyses such as frontier molecular orbitals, density of states (DOS), transition density matrix (TDM), binding energy (Eb), and open circuit voltage (Voc) were conducted. All the derivatives exhibited a comparable band gap (2.45–2.70 eV) manifesting absorption bands in the UV-Visible spectrum (590–463 nm), in solvent as well as in gaseous phase. Interestingly, smaller Eb values of 0.170 and -0.099 eV were observed for BTI5 and BTI6, respectively, suggesting a greater degree of charge transfer and improved exciton dissociation in these derivatives. These findings are further supported by TDM and DOS analyses, which confirm that all the studied compounds exhibit a higher charge transfer rate from highest occupied orbital to lowest unoccupied orbital (HOMO to LUMO). In conclusion, the good photovoltaic response observed for all the compounds suggests that these chromophores are reasonable candidates for development of efficient organic solar cells. [ABSTRACT FROM AUTHOR]

Currently, polycyclic aromatic compounds in organic solar cells (OSCs) have gained substantial consideration in research communities due to their promising characteristics. Herein, polycyclic aromatic hydrocarbons (PAHs) core-based chromophores (TTFD1-TTFD6) were designed by structural modifications of peripheral acceptor groups into TTFR. The density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations were carried out at B3LYP/6-311G (d, p) functional to explore insights for their structural, electronic, and photonic characteristics. The structural modulation unveiled notable electronic impact on the HOMO and LUMO levels across all derivatives, leading to decreased band gaps. All the designed compounds exhibited band gap ranging from 2.246 to 1.957 eV, along with wide absorption spectra of 897.071-492.274 nm. An elevated exciton dissociation rate was observed due to the lower binding energy values (Eb = 0.381 to 0.365 eV) calculated in the derivatives compared to the reference (Eb = 0.394 eV). Furthermore, data from the transition density matrix (TDM) and density of states (DOS) also corroborated the effective charge transfer process. Comparable results of Voc for reference and designed chromophores were obtained via HOMOdonor−LUMOPC71BM. The declining Voc order values was noted as TTFD5 > TTFD6 > TTFD4 > TTFD3 > TTFD2 > TTFD1 > TTFR. Interestingly, TTFD5 was found with the smallest energy gap and highest absorption value, resulting in better charge transference among all the derivatives. The results illustrated that the modification in indenofluorene based chromophores with end-capped small acceptors proved to be a significant approach in achieving favorable photovoltaic properties. [ABSTRACT FROM AUTHOR]

A photodiode based on zinc oxide is fabricated using a direct current DC sputtering system. The effect of the nitrogen (N) ratio to argon (Ar) on photoelectrical properties is investigated via current-voltage characteristics. The nitrogen is varied within the 0–100 cm3 range, while the argon is maintained constant during the deposition process. The Au/ZnO:N/nSi/Au photodiode exhibited a high rectification factor around 105. According to high obtained value of ideality factor n ~3 a non-ideal behavior of Au/ZnO:N/nSi/Au photodiode is revealed. Saturation current (Is) and barrier height (φB) are found to be around 1 nA and 0.84 eV, respectively. Besides, the series resistance of 100 Ω is calculated by Cheung method. The Au/ZnO:N/nSi/Au heterostructure exhibited a high photosensitivity of 104. The sputtered as-grown ZnO films on glass are characterized by SEM and EDX facilities. The grain sizes are found to be around 24 nm. [ABSTRACT FROM AUTHOR]

This study reports the room temperature testing of an InGaAs/InP photodetector, biased under linear sweep and/or parametric bias voltage for both modulated, and unmodulated 1550 nm wavelength illuminations. Charge transport of the photo-generated carriers is probed under absorber's electric field manipulations via parametric control of applied bias, readout element, and light intensity. The device exhibits three different illumination intensity dependent current signatures. Speed of the employed device is enhanced under relatively stronger electric fields ensuring higher drift, and reduced transit times. A three order reduction in the gain setting of the readout element results in ∼ 235 times large peak-current under 20 times smaller pulsed illumination of 0.2 μ W . This electric field enhancement decreases rise, and fall times under pulsed illumination from 225 ns to 115 ns , and 1.553 μ s to 1.143 μ s , respectively. But, the large photodetection plausibility, and reduced transit times ensuring relatively fast speed comes at the expense of ~ 5 order high noise activity in the device. It is also inferred that, overall noise spectrum of the device is not decided by simple generational processes in the absorber, but through the actual proportion of photo-generated carriers taking part in the real charge transport. [ABSTRACT FROM AUTHOR]

To improve the efficacy of organic solar cells (OSCs), novel small acceptor molecules (CTD1–CTD7) were designed by modification at the terminal acceptors of reference compound CTR. The optoelectronic properties of the investigated compounds (CTD1–CTD7) were accomplished by employing density functional theory (DFT) in combination with time-dependent density functional theory (TD-DFT). The M06 functional along with a 6-311G(d,p) basis set was utilized for calculating various parameters such as: frontier molecular orbitals (FMO), absorption maxima (λmax), binding energy (Eb), transition density matrix (TDM), density of states (DOS), and open circuit voltage (Voc) of entitled chromophores. A red shift in the absorption spectra of all designed chromophores (CTD1–CTD7) was observed as compared to CTR, accompanied by low excitation energy. Particularly, CTD4 was characterized by the highest λmax value of 685.791 nm and the lowest transition energy value of 1.801 eV which might be ascribed to the robust electron-withdrawing end-capped acceptor group. The observed reduced binding energy (Eb) was linked to an elevated rate of exciton dissociation and substantial charge transfer from central core in HOMO towards terminal acceptors in LUMO. These results were further supported by the outcomes from TDM and DOS analyses. Among all entitled chromophores, CTD4 exhibited bathochromic shift (685.791 nm), minimum HOMO/LUMO band gap of 2.347 eV with greater CT. Thus, it can be concluded that by employing molecular engineering with efficient acceptor moieties, the efficiency of photovoltaic materials could be improved. [ABSTRACT FROM AUTHOR]

This paper reports the fabrication and 60Co gamma radiation effects on the silicon heterojunction solar cells (SHJ). The SHJ solar cells were fabricated by using physical vapor deposition technique. An n-type Si wafer was used as a substrate. The intrinsic layer, hole selective layer and transparent conductive oxide were deposited above the substrate. A complete SHJ solar cell was fabricated in dimension of 1 × 1 cm2. The illuminated I–V characteristics of SHJ solar cell with A.M 1.5 are done using the solar simulator. The different electrical characteristics of solar cell such as short circuit current (Isc), open circuit voltage (Voc), fill factor (FF) and conversion efficiency (η) were studied. The fabricated SHJ solar cell displayed a conversion η of 9.09%, a Voc of 0.733 V, an Isc of 19.14 mA, and an FF of 64.74%. The fabricated SHJ solar cells are subjected to doses of 60Co gamma radiation ranging from 100 krad to 100 Mrad. As the gamma dose aincreased, the solar cell output parameters also reduced. FF decreased from 64.74 to 57.16%, and Voc decreased from 0.73 to 0.66 V. The Isc decreased to 7.825 from 19.14 mA. The η decreased from 9.09 to 2.98% for the fabricated silicon SHJ solar cell. [ABSTRACT FROM AUTHOR]

The curcuminoid class of organic compounds is very versatile which possesses applications over vast fields of science and technology. In the present investigation, we systematically designed six curcuminoid (Crmd) derivatives with symmetric and asymmetric structures, which are named as Crmd-1 to Crmd-6. We used 2,2-difluoro-4,6-divinyl-dioxaborinine moiety as a linker to design symmetric and asymmetric donor π-conjugation and acceptor configurations. Triphenylamine and triphenylborane are used as donor and acceptors which are intrinsically donor and acceptors owing to the presence of vacant p-orbital in boron and lone pair of electrons in nitrogen atoms, respectively. Density functional theory (DFT) is applied using M06/6-311G* method to calculate linear polarizability (α), and second hyperpolarizability (γ). The value of isotropic linear polarizability (αiso) and anisotropic linear polarizability (αiso) are 125.3 × 10–24 esu and 148.1 × 10–24 esu for Crmd-6, respectively. By comparative analysis, it is observed that the highest value of γ amplitude is calculated to be 6472.3 × 10–36 esu for Crmd-6. The robust increase in non-linear optical (NLO) polarizability is observed due to the asymmetric intramolecular charge transfer (ICT) and better D-π-A configuration in Crmd-6. Time dependent DFT calculations are performed to observe the origin of third-order NLO polarizabilities. Furthermore, frontier molecular orbitals, electron density difference, molecular electrostatic potential diagrams, and transition density matrix analysis demonstrate enhanced charge redistribution from the donor to the acceptor fragments. The use of modern computational tools highlights an effective ICT, which leads stronger third-order NLO response properties in designed curcuminoid derivatives. [ABSTRACT FROM AUTHOR]

Context: The purpose of the S01–S05 series of end-capped modified donor chromophores is to amplify the energy conversion efficiency of organic solar cells. Using quantum chemical modeling, the photophysical and photoelectric characteristics of the S01–S05 geometries are examined. Method: The influence of side chain replacement on multiple parameters, including the density of states (DOS), molecular orbital analysis (FMOS), exciton-binding energy (Eb), molecular electrostatic potential analysis, dipole moment (μ), and photovoltaic characteristics including open circuit voltage (VOC), and PCE at minimal energy state geometries, has been investigated employing density functional theory along with TD-DFT analysis. The molar absorption coefficient (λmax) of all the proposed compounds (S01–S05) was efficiently enhanced by the terminal acceptor alteration technique, as demonstrated by their scaling up with the reference molecule (SR). Among all molecules, S04 has shown better absorption properties with a red shift in absorption having λmax at 845 nm in CHCl3 solvent and narrow energy gap (EG) 1.83 eV with least excitation energy (Ex) of 1.4657 eV. All created donors exhibited improved FF and VOC than the SR, which significantly raised PCE and revealed their great efficiency as OSC. Consequently, the results recommended these star-shaped molecules as easily attainable candidates for constructing extremely efficient OSCs. [ABSTRACT FROM AUTHOR]

Context: Various innovative molecules have been designed and explored for use in organic photovoltaics. In this study, we devised novel molecules (KZ1–KZ7) specifically for organic solar cells (OSCs). The newly formulated acceptor compounds possess a lower bandgap (Eg = 1.85–2.02), along with bathochromic shift (λmax = 713–788 nm) compared to the reference (Eg = 2.04 eV and λmax = 774 nm). Moreover, the FMO results identified the distinct charge transfer from HOMO to LUMO, which was strongly corroborated by the TDM maps. Similarly, the new designed molecules show less excitation energy (Ex = 1.31–1.54(gas)) than reference (Ex = 1.72). Likewise, all designed molecules (KZ1–KZ7) have demonstrated an analogous open circuit voltage (Voc) with the donor polymer PTB7-Th. All seven designed molecules (KZ1–KZ7) exhibited more fill factor ranging from 97.08 to 97.29 than reference 95.25 and PCE of between 8 and 20% at short circuit current densities of 9, 12, and 15 mA cm−2. Overall, the findings support that designed molecules can be potential molecules for future practical applications. Methods: Geometric calculations were conducted with Gaussian 09W software, and the findings were visualized using Gauss View software. DFT and TD-DFT were employed to evaluate various parameters for R and designed molecules (KZ1–KZ7). Firstly, four functionals including B3LYP, CAM-B3LYP, MPW1PW91, and ωB97XD with 6-31G(d,p) DFT level were applied to R to decide the best level for results. After appropriate analysis, the MPW1PW91/6-31G(d,p) was selected for further examination by comparing the experimental and DFT-based absorption graphs of R. External and internal reorganization energy are the two main factors contributing to reorganization energy. External energy refers to changes in external environment, while internal energy deals with information related to internal geometrical symmetry or the internal environment. The effect of outside factors or external reorganizational energy is omitted because it creates too little change. [ABSTRACT FROM AUTHOR]

The tandem organic solar cell could absorb the complementarity sunlight spectra by the sub-cells based on the different energy gap of the active-layer materials. In this work, a wide-band gap of the organic material PTB7-Th: PC71BM is used as the front sub-cells active layer, and the narrow-band gap of PTB7-Th: IEICO-4F is used as the rear sub-cells active layer. The front and rear sub-cells present the complementary absorption spectra leading to the sufficiently improvement of the sunlight absorption. MoO3/Au/ZnO multilayer film is the interconnecting layer. ZnO film was prepared by the sputtering method is smaller root-mean-square than that of the film prepared by the solution synthesis, resulting in a good contact interfacial between the sub-cells. This is in favor of the JSC and FF of the tandem organic solar cell. Importantly, the short-circuit current density of the tandem solar cell is handily controlled by the active-layer concentration of the front sub-cell, the tandem cell exhibits an optimal PCE of 11.77% with a large VOC of 1.45 V. [ABSTRACT FROM AUTHOR]

Polymer solar cells (PSCs) with an inverted architecture are promising photovoltaic devices. The inverted device has clearly distinguishable electron and hole transport layers (ETL and HTL) compared to traditional PSCs with a direct structure. ETL and HTL ensure effective charge separation and transport, and their properties significantly affect the photovoltaic performance and stability of PSCs. In this research work, we studied the effect of the thickness and quality of zinc oxide (ZnO) ETL on dynamics of charge transport in FTO/ZnO/P3HT:IC60MA/MoOx/Ag devices and their photovoltaic performance. We observe that, when ZnO layer thickness is decreased, the power conversion efficiency (PCE) of the device sharply boosts reaching peak value and then steadily decreases. According to the impedance spectroscopy study, there are two competitive charge transfer processes in PSCs: electron transport from the photoactive layer to FTO through ZnO and charge recombination at the ZnO/P3HT:IC60MA interface. The kinetics of these charge transfer processes depends on ZnO thickness and quality. Our study indicates that there is a balance between charge transport and recombination rate at the thickness of the ZnO layer of approximately 50 nm. The champion device with ZnO ETL thickness of 54 nm has generated a short-circuit current of 9.5 mA/cm2, an open-circuit voltage of 0.6 V, and PCE of 3.2% under the light illumination with the intensity of 100 mW/cm2. [ABSTRACT FROM AUTHOR]

In this article, GaN/ InxGa1 − xN based solar cell with Si substrate and SiCN buffer layer is investigated with the help of modeling and simulation. The performance of the designed device is best suited for the low cost photovoltaic applications in terms of high open-circuit voltage (VOC) of 2.53 V, short-circuit current density (JSC) of 2.83 mA/cm2, Fill Factor (FF) of 76.98% and power conversion efficiency (η) of 4.02% under air mass (AM) 1.5G illumination. The mole fraction of Indium content in InxGa1 − xN plays a significant role in increasing the efficiency and open circuit voltage for improved device performance. A commercial Silvaco TCAD is used for simulation of GaN/InxGa1 − xN based solar cell for extracting the energy band gap, short-circuit current density, power (P) and the power conversion efficiency with different design parameters. [ABSTRACT FROM AUTHOR]

In this theoretical study, quantum chemical analysis of five novel non-fullerene donor molecules designed from recently reported highly efficient (11.5%) donor molecule P2TBR, containing non-fused ring central thiophene-benzene-thiophene core, 2-D benzodithiophene donors, and end capped 3-methylrhodanine acceptors, has been performed to evaluate the photovoltaic parameters and their application in organic solar cells. These donor molecules consist of centrally introduced acrylonitrile acceptors in between thiophene-benzene-thiophene core of P2TBR, namely M1. Compounds M2–M5 were designed from M1 containing ZOPTAN core, through peripheral acceptor group modification by 2-methylenemalononitrile (M2), methyl 2-cyanoacrylate (M3), 2-(5,6-difluoro-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene) malononitrile (M4), and 2-(3-methyl-5-methylene-4-oxothiazolidin-2-ylidene) malononitrile (M5). DFT and TD-DFT simulations of all molecules including reference were carried out using MPW1PW91 functional in conjunction with 6-31G (d, p) basis set. Optoelectronic properties, exciton dynamics, electron density distribution pattern, and charge mobility were further analyzed by absorption spectra, TDM plots, frontier molecular orbitals (FMO) analysis, and calculation of reorganization energies, respectively. Results reveal that central addition and end capped modification of acceptors in designed molecules proved to be effective strategy to finely tune the electronic and optical characteristics. Amongst all designed molecules, M4 exhibited improved opto-electronic parameters such as highest maximum absorption (695 nm) in chloroform, least band gap (2.24 eV), lowest values of λh (0.0034 eV), and λe (0.0054 eV) and lowermost binding energy (0.46 eV), because of mutual effect of extended pi-conjugation and significant electron pulling nature of terminal acceptors. Moreover, higher dipole moment, lower values of hole reorganization energy, and improved Voc of designed molecules than reference (R) make them efficient donors to enhance PCE of photovoltaic materials. [ABSTRACT FROM AUTHOR]

Investigations of the influence of the optimized process of wet chemical treatment on the optical characteristics of the silicon monocrystalline wafers surface have been carried out. It was found that chemical treatment of a silicon wafer surface with a KOH solution with a concentration of 45% in deionized water at a temperature of 75°C for 4 min leads to etching of the damaged surface layer, thereby reducing the number of surface recombination centers of charge carriers. The use of ozone for cleaning from organic and other contaminants and the replacement of isopropyl alcohol in a solution with KOH replaced by ALKATEX surfactant allows the plates to be textured at higher temperatures in a relatively short time and to reduce material costs. The use of an optimized wet chemical treatment process makes it possible to texture monocrystalline silicon wafers and obtain a pyramid on the surface with a base width from 1 to 4 μm and a height of ~1.5–3 μm, which will make it possible to reduce the reflection coefficient of electromagnetic radiation by more than 3 times in relation to plates with a smooth surface, in the spectral range of 600–800 nm, the reflection coefficient decreased to a value of 8.7%. A decrease in the reflection coefficient from the silicon wafer surface should lead to an increase in the transmittance of the supplying electromagnetic radiation of the silicon wafer, which will increase the number of the solar cell quanta penetrating the photoactive region, as a result of which the magnitude of the short-circuit current and the open-circuit voltage should increase. Investigation of the load current–voltage characteristic of a heterojunction with an intrinsic thin-layer (HIT) solar cell based on a textured monocrystalline silicon wafer showed an efficiency value of 22.92% under standard test conditions. [ABSTRACT FROM AUTHOR]

Organic-inorganic metal halide perovskite materials, i.e., ABX3 (A = methylammonium, B = Pb, X = Cl, Br, I) have been proved to be outstanding for solar energy conversion. They provide a solution to renewable energy problems with good efficiency and cost-effective technology. Here, we report the initial calculations done by solving Kohn-Sham equations by the use of density function theory. The electronic structural and band gap of CH3NH3PbI3 material are obtained by using different exchange-correlation potential (PBE, PBE-sol, GGA). Further, solar cell devices with CH3NH3PbI3 as absorption layer and CdS/TiO2/ZnTe as buffer layer have been modeled; device physics is discussed and performance of solar cell structure is analyzed in terms of short circuit current density, open circuit voltage, efficiency, fill factor, and quantum efficiency. The maximum efficiency of CH3NH3PbI3 solar cell is found to be 19.6% with TiO2 buffer layer, whereas efficiency with ZnTe buffer layer is also comparable which is 19.5%. Further the effect of layer thickness and temperature are analyzed for maximum efficiency. [ABSTRACT FROM AUTHOR]

This work presents the results of experimental analysis of the correlation between open-circuit voltage at 0% and the state of charge of a set (3 × 6) of high-temperature valve-regulated lead acid batteries, which provides a valuable health diagnosis tool when performing predictive maintenance actions. The proposed test could be executed after any emergency event in the battery system. It offers an alternative to the integration ampere hours, simplifying the diagnostic system, and can be used in many applications where the diagnosis can be made by monitoring the discharge voltage to a defined controlled value. By testing three different sealed, high-temperature lead acid battery models, it has been proved that open-circuit-voltage measurement at 0% state of charge is valid to evaluate health status and is applicable to different manufactures. In addition, the first derivative value calculation of the relaxation voltage over time provides accurate correlation with the state of health of the battery. The method proposed minimizes diagnosis times providing an easier way to implement the method in real systems. [ABSTRACT FROM AUTHOR]

The study provides a multifunctional measuring device that searches for the maximum energy output using a certain algorithm and calculates the fill factor and efficiency of a solar module. It also monitors the air temperature and relative humidity, the temperature of the solar module, the level of solar radiation, wind speed, and current and voltage of the solar module. An electrical circuit for measuring the current–voltage characteristic of photovoltaic modules is proposed. In addition, rechargeable batteries allowing measurements without connecting the device to a power supply ensure autonomy of the device. An algorithm is proposed for finding the point of maximum power of a photovoltaic module. The device is developed on the basis of an ATmega2560 microcontroller with additional sensors. The measuring device software sends all acquired data from the device to a computer to be saved in a database. [ABSTRACT FROM AUTHOR]

This paper presents the results of experimental studies of spectral, dark current–voltage and light load characteristics of the selenide–copper–gallium–indium (Cu(In, Ga)Se2) solar cell. Тhe main fundamental parameters of the photoactive semiconductor layer Cu(In, Ga)Se2, such as the band gap, the resistivity of the layer, the equilibrium majority–carrier concentration, the lifetime and the product μnτn of nonequilibrium minority carriers from the spectral, photoelectric and dark current–voltage characteristics are determined. Based on an analysis of the light-load current–voltage characteristics at various solar radiation powers (50–1000 W/m2), the main parameters of the p–n junction were determined, as well as the nonideality factor and the magnitude of the reverse diode saturation current; a photogeneration mechanism was established in the studied solar radiation range, which had the character of a diffusion mechanism, where carrier recombination in the photoactive layer did not have a significant effect. We found that in conditions of real solar lighting (Рrad = 50–1000 W/m2), the output parameters of the solar cell – short-circuit current, open circuit voltage, the maximum output power increases with Рrad. The fill factor (FF) of the light-current–voltage characteristics has a maximum at Рrad ≈ 200 W/m2, and an efficiency has a maximum value at Рrad ≈ 600 W/m2. The observed dependences of FF and efficiency are explained by the dependence of the series (Rser) and shunt (Rsh) resistance of a solar cell on Prad. To maintain the efficiency of a solar cell based on thin-film layers Cu(In, Ga)Se2, equally high in conditions of increased radiation, as well as in conditions of low solar radiation, it is necessary that Rser decreases and Rsh does not change with Prad. [ABSTRACT FROM AUTHOR]

This research paper presents a comprehensive study on the design and photovoltaic parameters of azobenzene type 24 photo switches (PSs) of triazole by density functional theory (DFT). The focus was on investigating how to create a long-range push-pull effect of different substituents on the PS properties for their application in photovoltaics by further substituent decoration. Their range of values for the maximum wavelength (λmax) ranged 315-556 nm while their HOMO-LUMO energies (Egaps) were 0.57-6.35eV. The stability of the PS was evaluated by measuring hardness (η) and softness (σ) values. Additionally, photovoltaic parameters such as open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and maximum power (Pmax) were calculated to assess the performance of the PS as photovoltaic materials. The results revealed that PSs 6 exhibited promising photovoltaic parameters to include Voc values ranging from 0.4-1.63eV, FF values ranging from 0.5438-0.929, Jsc values ranging from 19.27-50.75 mA/cm2, and Pmax values ranging from 14.72-75.91W. This indicates its potential as an efficient light-harvesting material for photovoltaic applications. Moreover, this study presents a pioneering investigation on the correlation between rotational velocity (R) and Mayer bond index (MBI) for the first time. The findings revealed a significant correlation between R and MBI, providing valuable insights into the structural dynamics of the PS. This novel finding opens up new avenues for understanding the structural dynamics of PS and their potential applications in various fields, including photovoltaics. The study provides valuable insights into the structure-property relationships of azobenzene-based PS and their suitability for photovoltaic devices. Further investigations are warranted to optimize the design of the PS, enhance their photovoltaic performance, and explore the underlying mechanisms of the correlation between R and MBIs.Graphical Abstract: This research paper presents a comprehensive study on the design and photovoltaic parameters of azobenzene type 24 photo switches (PSs) of triazole by density functional theory (DFT). The focus was on investigating how to create a long-range push-pull effect of different substituents on the PS properties for their application in photovoltaics by further substituent decoration. Their range of values for the maximum wavelength (λmax) ranged 315-556 nm while their HOMO-LUMO energies (Egaps) were 0.57-6.35eV. The stability of the PS was evaluated by measuring hardness (η) and softness (σ) values. Additionally, photovoltaic parameters such as open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and maximum power (Pmax) were calculated to assess the performance of the PS as photovoltaic materials. The results revealed that PSs 6 exhibited promising photovoltaic parameters to include Voc values ranging from 0.4-1.63eV, FF values ranging from 0.5438-0.929, Jsc values ranging from 19.27-50.75 mA/cm2, and Pmax values ranging from 14.72-75.91W. This indicates its potential as an efficient light-harvesting material for photovoltaic applications. Moreover, this study presents a pioneering investigation on the correlation between rotational velocity (R) and Mayer bond index (MBI) for the first time. The findings revealed a significant correlation between R and MBI, providing valuable insights into the structural dynamics of the PS. This novel finding opens up new avenues for understanding the structural dynamics of PS and their potential applications in various fields, including photovoltaics. The study provides valuable insights into the structure-property relationships of azobenzene-based PS and their suitability for photovoltaic devices. Further investigations are warranted to optimize the design of the PS, enhance their photovoltaic performance, and explore the underlying mechanisms of the correlation between R and MBIs. [ABSTRACT FROM AUTHOR]

Insulating zirconia has attracted increasing attention in industrial applications due to its excellent hardness, chemical stability, and corrosion resistance. However, insulating zirconia is difficult to machine by using traditional cutting techniques. In this paper, the high-speed wire electrical discharge machining (HS-WEDM) process of insulating zirconia is carried out with the assisting electrode method. The machining characteristics of insulating zirconia with HS-WEDM process are investigated, which include the study of effect of open-circuit voltage ( U) on machining speed, discharge gap, surface roughness, surface microtopography, and electrical discharge status. The experimental results indicate that when U is changed from 90 to 150 V, the machining speed increases from 1.02 to 2.61 mm/min and the machining gap increases from 15.55 to 26.67 μm. With the increasing U, the percentage of electrical discharge with high resistance increases, the percentage of electrical discharge with low resistance changes only slightly, and the percentage of short circuit with low resistance decreases. Moreover, when grooves are machined into transverse and longitudinal direction of the workpiece, the two machined surfaces of one grove present different surface characteristics. [ABSTRACT FROM AUTHOR]

Micro-SOFCs, miniaturized solid oxide fuel cells (SOFCs) for low temperature operation, are being developed as a power source for portable electronics. Reducing the thickness of the electrolyte and the adoption of acceptor-doped ceria as an electrolyte material are important to minimize the Ohmic resistance at low temperature. Acceptor-doped ceria thin-films are often deposited on nano-porous metal substrates to reduce cracking of the thin electrolyte. However, due to the difficulty of depositing a pore-free electrolyte on a porous medium, the cells often show the low open circuit voltages (OCVs). In this study, we have deposited ∼1 μm-thick Gd-doped ceria on a nano-porous nickel film to assess whether a thin-film, metal-supported GDC can be deposited as a pore-free layer and would thus be suitable as an electrolyte of micro-SOFCs. The Ni-supported GDC cell showed an OCV of ∼0.92 V at 450 °C under a hydrogen/air gradient. The high OCV verifies that the thin-electrolyte layer, deposited on porous Ni using the pulsed laser deposition (PLD) method, is dense enough to prevent gas leakage as also observed in its microstructure. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) can 'treat' wastewater but individually are thermodynamically restricted. Scale-up might, therefore, require a plurality of units operating in a stack which could introduce losses simply through fluidic connections. Experiments were performed on two hydraulically joined MFCs (20 cm apart) where feedstock flowed first through the upstream unit (MFC) and into the downstream unit (MFC) to explore the interactive effect of electrical load connection, influent make-up and flow-rate on electrical outputs. This set-up was also used to investigate how calculating total internal resistance based on a dynamic open circuit voltage (OCV) might differ from using the starting OCV. When fed a highly conductive feedstock (~4,800 μS) MFC dropped approximately 180 mV as progressively heavier loads were applied to MFC (independent of flow-rate) due to electron leakages through the medium. The conductivities of plain acetate solutions (5 and 20 mM) were insufficient to induce losses in MFC even when MFC was operating at high current densities. However, at the highest flow-rate (240 mL/h) MFC dropped by approximately 100 mV when using 5 and 220 mV using 20 mM acetate. When the distance between MFCs was reduced by 5 cm, voltage drops were apparent even at lower flow-rates, (30 mL/h decreased the voltage by 115 mV when using 20 mM acetate). Shear flow-rates can introduce dissolved oxygen and turbulence all capable of affecting the anodic biofilm and redox conditions. Calculating total internal resistance using a dynamic OCV produced a more stable curve over time compared to that based on the starting constant OCV. [ABSTRACT FROM AUTHOR]

Electrolyte design for Li ion batteries was approached by means of comparison of faradaic and non-faradaic currents. The faradaic current by the movement of Li+ ions was dependent on the composition of the electrolyte and was related to the battery capacity; the higher the capacity, the greater the current by the faradaic reaction. The open circuit potential of the electrode with a greater faradaic current decreased at a slower rate than that of the electrode with a smaller faradaic current. This analysis method can be used to prepare an optimal electrolyte of an actual Li ion battery, especially when developing batteries with excellent high-rate discharge capabilities and low temperature discharge properties. [ABSTRACT FROM AUTHOR]

The open circuit voltage (OCV) model of the solid polymer electrolyte (SPE)/salt system in lithium batteries is established by combining concentrated solution theory with the modified double lattice-non-random (MDL-NR) model which describes the non-ideal behavior of the salt activity in the polymer electrolyte. The activity parameters are obtained from the phase diagram for the given systems and used to describe the OCV of the corresponding systems with one additional parameter, transport number,t. The proposed model agrees very well with the OCV data for various PEO/salt systems. [ABSTRACT FROM AUTHOR]

Sealing technology is currently considered a top-priority task for planar solid oxide fuel-cell stack development. Compressive mica seals are among the major candidates for sealing materials due to their thermal, chemical, and electrical properties. In this paper, a comprehensive study of mica seals is presented. Two natural micas, muscovite and phlogopite, were investigated in either a monolithic single-crystal sheet form or a paper form composed of discrete mica flakes. A "hybrid" mica seal, developed after identification of the major leak paths in compressive mica seals, demonstrated leak rates that were hundreds to thousands times lower than leak rates for conventional mica seals. The hybrid mica seals were further modified by infiltration with wetting materials; these "infiltrated" micas showed excellent thermal cycle stability with very low leak rates (10-3 sccm/cm). The micas were also subjected to studies to evaluate thermal stability in a reducing environment as well as the effect of compressive stresses on leak rates. In addition, long-term open circuit voltage measurements versus thermal cycling showed constant voltages over 1,000 cycles. The comprehensive study clearly demonstrated the potential of compressive mica seals as sealing candidates for solid oxide fuel cells. [ABSTRACT FROM AUTHOR]