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Unmanned aerial vehicles (UAVs) nowadays are getting soaring importance in many aspects like agricultural and military fields. A hybrid power system is a promising solution toward high energy density and power density demands for UAVs as it integrates power sources like internal combustion engine (ICE), fuel cell (FC) and lowcapacity lithium-polymer (LIPO) batteries. For robust energy management, accurate state-of-charge (SOC) estimation is indispensable, which necessitates open circuit voltage (OCV) determination and parameter identification of battery. The presented research demonstrates the feasibility of carrying out incremental OCV test and even dynamic stress test (DST) by making use of the hybrid powered UAV system itself. Based on battery relaxation terminal voltage as well as current wave excitation, novel methods for OCV determination and parameter identification are proposed. Results of SOC estimation against DST through adaptive unscented Kalman filter (AUKF) algorithm show that parameters and OCV identified with longer relaxation time don't yield better SOC estimation accuracy. Besides, it also discloses that OCV played the vital role in affecting SOC estimation accuracy. A detailed analysis is presented showing that mean discharging rate and current wave amplitude are the major factors which affect the quality of OCV identified related to SOC estimation accuracy. [ABSTRACT FROM AUTHOR]

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]

In recent years, we have witnessed significant advancements in the production of solar cells with a reduction in cost and an increase in their efficiency. One of the stages in creating advancements in new cells is evaluating their performance under different conditions using simulations before their fabrication. In this article, the structure of a multi-junction solar cell composed of Ge layers, InAlGaAs alloys, and InAlGaP alloys will be comprehensively examined. To achieve the highest efficiency, the lowest absorbing layer of the solar cell (Ge solar cell) will initially be optically simulated and then electrically simulated. After optimizing the Ge solar cell, the intermediate layers between the cells (tunnel junctions) and then the upper absorbing layers will be optimized in sequence. Optimization of solar cells in each absorbing layer refers to selecting the appropriate thickness, impurity density, and molar percentage of the layers to achieve the highest efficiency. According to simulation results, an efficiency of over 49% has been achieved for the 5-junction cell. [ABSTRACT FROM AUTHOR]

Abstract 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 (E b = 0.381 to 0.365 eV) calculated in the derivatives compared to the reference (E b = 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 V oc for reference and designed chromophores were obtained via HOMOdonor−LUMOPC71BM. The declining V oc 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.

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 work provides an extended description of the tools developed in the Wolfram Mathematica environment to characterize proton exchange membrane (PEM) fuel cells. These tools, with their user-friendly interface, facilitate the calculation of the main parameters required to obtain the PEM fuel cell polarization curve, offering a seamless and intuitive experience. Various mathematical models and algorithms are coded to accurately calculate the parameters needed for the polarization curve analysis. This study presents the development and validation of a computational tool designed to simulate the performance of proton exchange membrane (PEM) fuel cells. The tool integrates thermodynamic and electrochemical equations to predict key operational parameters, and was validated using experimental data from a commercial Ballard® PEM fuel cell to ensure its accuracy. The validation process involved comparing the numerical predictions with empirical measurements under various operating conditions. The results demonstrate that the computational tool accurately replicates the performance characteristics observed in the experimental data, confirming its reliability and instilling confidence in its use for simulating PEM fuel cell behavior. This tool offers a valuable resource for optimizing fuel cell design and operation, providing insights into the efficiency, output, and potential areas for improvement. Future work will expand the tool's capabilities to include degradation mechanisms and long-term performance predictions. This advancement underscores the tool's potential as a comprehensive solution for academic research and industrial applications in fuel cell technology. [ABSTRACT FROM AUTHOR]

Shepherd's model is considered as an improved and simple to-apply battery dynamic model. The experimental nominal parameters of five different capacities of Lithium-ion Polymer battery samples are established from the manufacturer's datasheets. The discharge and charge dynamics of the battery sample with the highest capacity, 3100 mAh are examined and validated. The clarity to derive the dynamic model parameters from the battery datasheet is a fascinating attribute of this model. The experimental database is utilized to study its dynamic feature and subsequently the dynamic battery model, which describes the relationship between the state of charge, the open circuit voltage and ambient temperature. The model is implemented and simulated by using MATLAB/Simulink tools. The current charge-discharge equations describe the optimized electrochemical activities with sustainable long cycle duration. The temperature model brings under control the aging effect, which plays down on the energy capacity of the battery. A steady load of 5 A is linked to the battery and used in a detail simulation of a direct current machine in determination of load effect. The compatibility of these equations and simulations implies that Shepherd's model is promising to provide guidelines for the analysis of discharge and charge in rechargeable polymer based lithium-ion batteries. The results show that the model can precisely illustrate the dynamic behavior of the batteries. [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]

The lead-free CH3NH3SnI3 perovskite is essential for absorbing light in perovskite solar cells (PSCs). In a photovoltaic (PV) device setup of FTO/STO/CH3NH3SnI3/Spiro-OMeTAD/Au, it demonstrates excellent PV performance. This device includes sulfur-doped tin oxide (STO) for the layer of electron transport (ETL), CH3NH3SnI3 as the absorber, and the hole transport layer (HTL) is Spiro-OMeTAD. The upper and back contacts consist of fluorine-doped tin oxide (FTO) and gold (Au), connecting these layers. Several parameters were estimated using the Solar Cell Capacitance Simulator (SCAPS-1D) program, including the thickness, acceptor and donor densities, series and shunt resistances, and temperature. The absorber, HTL, ETL, and FTO thicknesses were set at 1000 ​nm, 100 ​nm, 150 ​nm, and 50 ​nm, respectively, to find the perfect configuration. Densities of acceptors and donors were maintained at 1019 ​cm−3, 2.0 ​× ​1019 ​cm−3, 2.0 ​× ​1018 ​cm−3, and 1018 ​cm−3 for the absorber, HTL, ETL, and FTO, respectively, at an operating temperature of 300K. The device configuration exhibited reduced series resistance and increased shunt resistance, optimized with a back contact metal of Au. The idealized model demonstrated significant PV execution characteristics, including 1.117 ​V for open-circuit voltage (VOC), 28.88 ​mA/cm2 for short-circuit current density (JSC), 88.47 ​% for fill factor (FF), and 28.55 ​% for power conversion efficiency (PCE) under the AM1.5G spectrum. Additionally, the device displayed an average quantum efficiency (QE) of approximately 88.30 ​% at visible light wavelengths.

Abstract 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 (λ max), binding energy (E b), transition density matrix (TDM), density of states (DOS), and open circuit voltage (V oc ) 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 λ max 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 In this paper the influence of different parameters such as active layer thickness, light intensity and charge separation distance on the photocurrent-voltage, short circuit current density (Jsc) and open circuit voltage (Voc) characteristics in MEH-PPV:PCBM BHJ devicesis studied. For this purpose, the numerical continuum modelbased on drift-diffusion approximation is used. The J-V characteristics of MEH-PPV:PCBM BHJ devices under illumination change considerably with varying the active layer thickness from 40nm to 280nm. In these devices, as the active layer thickness increases from 40 nm to 120 nm the short-circuit current density increases dramatically. The open circuit voltage (Voc) is partially affected by varying the active layer thickness. In these devices, as the light intensity increases, the current density would increase at low voltages. Also, as the charge separation distance “a” increases, The exciton dissociation rate (kdissnexc) and current density would decrease.

Metal halide perovskites are promising light absorbers for multijunction photovoltaic applications because of their remarkable bandgap tunability, achieved through compositional mixing on the halide site. However, poor energy‐level alignment at the interface between wide‐bandgap mixed‐halide perovskites and charge‐extraction layers still causes significant losses in solar‐cell performance. Here, the origin of such losses is investigated, focusing on the energy‐level misalignment between the valence band maximum and the highest occupied molecular orbital (HOMO) for a commonly employed combination, FA0.83Cs0.17Pb(I1‐xBrx)3 with bromide content x ranging from 0 to 1, and poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA). A combination of time‐resolved photoluminescence spectroscopy and numerical modeling of charge‐carrier dynamics reveals that open‐circuit voltage (VOC) losses associated with a rising energy‐level misalignment derive from increasing accumulation of holes in the HOMO of PTAA, which then subsequently recombine non‐radiatively across the interface via interfacial defects. Simulations assuming an ideal choice of hole‐transport material to pair with FA0.83Cs0.17Pb(I1‐xBrx)3 show that such VOC losses originating from energy‐level misalignment can be reduced by up to 70 mV. These findings highlight the urgent need for tailored charge‐extraction materials exhibiting improved energy‐level alignment with wide‐bandgap mixed‐halide perovskites to enable solar cells with improved power conversion efficiencies. [ABSTRACT FROM AUTHOR]

The discovery of novel electrode materials based on two-dimensional (2D) structures is critical for alkali metal-ion batteries. Herein, we performed first-principles computations to investigate functionalized MXenes, Mo2BT2 (T = O, S), which are also regarded as B-based MXenes, or named as MBenes, as potential anode materials for Li-ion batteries and beyond. The pristine and T-terminated Mo2BT2 (T = O, S) monolayers reveal metallic character with higher electronic conductivity and are thermodynamically stable with an intrinsic dipole moment. Both Mo2BO2 and Mo2BS2 monolayers exhibit high theoretical Li/Na/K storage capacity and low ion diffusion barriers. These findings suggest that functionalized Mo2BT2 (T = O, S) monolayers are promising for designing viable anode materials for high-performance alkali-ion batteries. [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]

Lead halide perovskites have revolutionized the field of optoelectronics (such as photovoltaics and light emitting diodes) demonstrating extraordinary material properties despite being formed at low temperatures. However, ion migration in the bulk or at the interfaces results in stability issues especially in devices where metal electrodes directly interface with the perovskite film. Utilizing the switchable photovoltaic phenomenon (SPV) in halide perovskites as a measure of ion migration and electrochemical reactions within them, Cs0.05MA0.15FA0.70PbI2.5Br0.5 triple cation perovskite, widely used in photovoltaics is evaluated. The various factors determining the SPV, including electric field magnitudes, type of metal contacts, Illumination conditions, and temperature is systematically measured. This study reveals the roles of electrode work functions and reactivities on ion migration and local electronic structure modulation. ITO electrodes demonstrated the highest open‐circuit voltage (Voc) about 0.85 V while Ag electrodes developed conductive filaments. However, the Voc distribution for Ti and Cr electrodes shows a more pronounced linear correlation with the poling electric field strength. Insights from this lateral design are directly relevant to transistor and memristor architectures and offer inputs into the design of perovskite‐based photovoltaic/optoelectronic devices. [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 field of organic solar cells has witnessed notable advancements in the past few years, mostly due to the development of novel materials for the active layer. The current investigations reveal the potential of nine previously unexplored molecules (TP1–TP9) designed by end group modification of TPT4F molecule. These molecules were investigated at MPW1PW91/6‐31G (d, p) with DFT and TD‐DFT approach to study the various photovoltaic and geometrical parameters. The results obtained through computations indicated improvement in the investigated parameters. The terminal group modification shifted the absorption maximum towards longer wavelength in the UV‐visible region. Highly conjugated modified acceptors reduced the band gap. The lower excitation energies increased the rate of charge transfer. The designed molecules showed improved excited state lifetime in comparison to the reference. The open circuit voltage was determined using the PTB7 polymer, which exhibited a noticeable improvement, especially in TP1 (1.70 eV), TP3 (1.75 eV), TP4 (1.68 eV), TP6 (1.85 eV), and TP7 (1.75 eV) when compared with reference (1.59 eV). Moreover, charge transfer investigations of designed molecules with PTB7 complex were performed by analyzing the concentration of charge transfer over molecular orbitals, that is, HOMO to LUMO. All of the preceding investigations targeted to achieve high‐efficiency organic cells reveal that the altered molecules can be considered effective candidates to tackle future energy problems. [ABSTRACT FROM AUTHOR]

Photoinduced intermolecular charge transfer (PICT) determines the voltage loss in bulk heterojunction (BHJ) organic photovoltaics (OPVs), and this voltage loss can be minimized by inducing efficient PICT, which requires energy‐state matching between the donor and acceptor at the BHJ interfaces. Thus, both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient PICT. In this study, an effective method for quantifying the hot state matching of OPVs was developed. The degree of energy‐state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor (MF) calculated from the modified optical density of the BHJ. Furthermore, the correlation between the open‐circuit voltage (Voc) of the OPV device and energy‐state matching at the BHJ interface was investigated using the calculated MF. The OPVs with small absolute MF values exhibited high Voc values. This result clearly indicates that the energy‐state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs. Because the MF indicates the degree of energy‐state matching, which is a critical factor for suppressing energy loss, it can be used to estimate the Voc loss in OPVs. [ABSTRACT FROM AUTHOR]

This study focuses on conceptualization and development of a battery management system (BMS) with two main functions, battery monitoring and management, in the context of brushless direct current motors (BLDCs). The main challenge in variable estimation is to protect the battery from potential risks during the charge and discharge cycle. The new proposed resolution combines a comprehensive BMS with monitoring capabilities for charge (SoC), health (SoH), voltage, current and battery temperature. In addition, a protective mechanism is incorporated to prevent variables from overshooting safety parameters. This research uses two different methodologies for estimating SOC, coulomb counting and open circuit voltage. In experimental tests, resistance potentiometers of 1,650, 3,300 and 0 were used, with SoC estimates of 37%, 19% and 65%, while coulomb counting method has a marginal error of 1.13%. On the contrary, the open-circuit voltage method generated a SoC estimate of 0% for all potentiometer resistance, with an error rate of 0.64 %. As a result, the open circuit voltage method is chosen because of its superior accuracy compared to the coulomb counting method. The state assessment of the battery showed a value of 100% after seven cycles. In addition, a protective system has been implemented to ensure that battery variables remain within the safe thresholds throughout the charge and discharge process. Consequently, the implementation of this BMS is expected to significantly improve overall performance and extend battery life.

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This research investigates characterization of low lying excitations of newly designed organic dyes for their local excited and charge transfer-related molecular switching attributes such as donor-acceptor relations against the carbazole bridge. The eight new dyes, having 4 symmetrical (Syn-A-D) and 4 antisymmetric (Anti-A-D) arrangements showed how the push-pull effect can operate to create the charge transfer phenomenon. Their absorption energies (E) for Syn dyes ranged from 2.98 eV to 4.07 eV, with corresponding wavelengths (λmax) ranging from 304 nm to 415 nm. While for their Anti arrangements, it ranged from 1.62 eV to 3.99 eV, with corresponding λmax values as 310-617 nm. Syn-C1 with an ionization potential (IP) of 6.59 eV and an electron affinity (EA) of 2.04 eV can be predicted to be more chemically stable compared to Anti-C2 with an IP of 5.16 eV and an EA of 3.86 eV. Syn-C also has the highest Voc (3.24 eV) and Pmax (22.35 W), indicating that it has the potential to be more chemically stable as compared to the other dyes. The findings of this research contributed to a better understanding of the molecular switching attributes of carbazole-based organic dyes, which could have implications for various applications, including optoelectronics and energy conversion devices. This research explores on characterizing low lying excitations of newly designed organic dyes for their local excited and charge transfer related molecular switching attributes as donor-acceptor relations against the carbazole bridge. The eight new dyes, having 4 symmetrical (Syn-A-D) and 4 antisymmetric (Anti-A-D) arrangements showed that how the push-pull effect can operate to create the charge transfer phenomenon. [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]

Most investigations on flow batteries (FBs) make the assumption of perfectly mixed electrolytes inside the tanks without estimating their likelihood, while specific analyses are missing in the literature. This paper presents a pioneering investigation of the electrolyte flow dynamics inside FB tanks. This study considers the Open Circuit Voltage (OCV) measured at the stack of a 9 kW/27 kWh Vanadium FB with 500 L tanks. Order-of-magnitude estimates of the measured dynamics suggest that differences in densities and viscosities of the active species drive gradients of concentrations with different patterns in the positive and negative tanks and in charge and discharge, affected by current and flow rate, which result in significant deviation from homogeneity, affecting the State of Charge (SoC) of the electrolytes flowed into the stack and thus the FB performance. In particular, stratifications of the inlet electrolytes may appear which are responsible for delays in reaching the outlets, with initial plateau and following step (s) in the SoC at the stack. These events can have a major impact in the performance of industrial FBs with large tanks and suggest that specific tank designs may improve the overall dynamics, calling for further analysis. [ABSTRACT FROM AUTHOR]

Continuous monitoring of large-scale solar photovoltaic (PV) installations is necessary to check the deterioration and monitor the performance of the PV plant. Fault diagnosis is crucial to ensure the PV plant operates safely and reliably. This paper presents a diagnosis methodology based on current-voltage (I-V) and PV characteristics to monitor and assess the behavior of solar PV. In this paper, I-V curve characterization using an I-V curve tracer is used to check the deterioration and diagnosis of the PV panels. The real-time performance of the 50.4 kWp rooftop solar grid interfaced PV plant is investigated and analyzed using I-V and PV curve tracers in real-time conditions. The overall performance of solar PV is assessed on a real-time test system in different scenarios such as variable climatic conditions, partial shading conditions, aging of solar panels, short circuit conditions, and dust decomposition. Furthermore, the performance assessment of solar PV is evaluated using performance indicators such as open circuit voltage index, short circuit current index, fill factor, and performance ratio. [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]

Density functional theory (DFT) and time dependent DFT (TD‐DFT) techniques are used to explore six donor‐pi‐acceptor (D−A) type sensitizers that comprise coumarin as the donor unit and cyanoacrylic acid as the acceptor unit. It is examined how adding a spacer bridge like 3,4‐ethylenedioxythiophene (EDOT) affects the system. The introduction of EDOT leads to destabilization of highest occupied molecular orbital (HOMO) in both bare and TiO2 anchored sensitizers. The frontier molecular orbital (FMO) also depicts an effective intramolecular charge transfer from the EDOT unit to the acceptor unit in bare sensitizers and to the TiO2 core in TiO2 anchored sensitizers respectively. The FMO diagram of TiO2 anchored non‐bridged sensitizers reveals an electron‐deficient sensitizer unit coupled to an electron‐rich TiO2 core resulting in a poor charge transfer. The calculated Voc values are also found to be more for EDOT based sensitizers and hence making the EDOT bridged sensitizers efficient for DSSC application. According to the TD‐DFT investigation, the EDOT bridging sensitizers exhibit red‐shifted vertical excitation when compared to the corresponding non bridged sensitizers, which is consistent with the experimental data reported previously. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have become a widely studied class of semiconductors for various optoelectronic devices. The possibility to tune their bandgap (Eg) over a broad spectral range from 1.2 eV to 3 eV by compositional engineering makes them particularly attractive for light emitting devices and multi‐junction solar cells. In this metadata study, data from Peer‐reviewed publications available in the Perovskite Database (www.perovskitedatabase.com) is used to evaluate the current state of Eg tuning in wideEg MHP semiconductors. Recent literature on wide Eg MHP semiconductors is examined and the data is extracted and uploaded onto the Perovskite Database. Beyond describing recent highlights and scientific breakthroughs, general trends are drawn from 45,000 individual experimental datasets of MHP solar cell devices. The historical evolution of MHP solar cells is recapitulated, and general conclusions are drawn about the current limits of device performance. Three dominant causes are identified and discussed for the degradation of performance relative to the Shockley‐Queisser (SQ) model's theoretical limit for single‐junction solar cells: 1) energetically mismatched selective transport materials for wide Eg MHPs, 2) lower optoelectronic quality of wide Eg MHP absorbers, and 3) dynamically evolving compositional heterogeneity due to light‐induced phase segregation phenomena. [ABSTRACT FROM AUTHOR]

The non-fullerene acceptor (NFA) chromophores have sparked scientific and economic interest, due to their rapid advancements in power conversion efficiencies. Therefore, a series of new chlorothiazole based compounds (STM1-STM6) with A1–π–A2–π–A1 configuration was designed using reference chromophore (STMR). Structural modifications were made via incorporating selenophene and extended acceptor units, to enhance photovoltaic response in the designed materials. Density functional theory/time dependent-density functional theory (DFT/TD-DFT) calculations were executed at M06/6-311G (d,p) level to investigate key electronic and photovoltaic properties of STM1-STM6. So, various analyses such as UV–Visible, frontier molecular orbitals (FMOs), transition density matrix (TDM), density of states (DOS), open circuit voltage (Voc) and binding energy (Eb) were conducted to comprehend the photovoltaic properties. The designing in structural aspects with terminal acceptors and π-linker induced a reduction in energy gaps (ΔE = 2.078–2.237 eV) with an enhancement in the bathochromic shift (λmax = 744.650–798.250 nm in chloroform) than reference compound. A higher exciton dissociation rate was observed in all the compounds due to lower binding energy values (Eb = 0.525–0.572 eV). Additionally, TDM and DOS findings further endorsed the effective charge delocalization from HOMO to LUMO. Among all the examined compounds, STM3 exhibited the smallest band gap (2.078 eV), highest absorption maxima (798.250 nm), and the lowest exciton binding energy (0.525 eV), indicating significant electronic properties. Moreover, Voc analysis was conducted with respect to HOMOPBDBT-LUMOacceptor for all the designed chromophores; consequently, STM2 demonstrated a substantial Voc value of 1.647 V. Similarly, electron hole analysis was also conducted and significant electron and hole density was observed in all the investigated compounds, especially in STM2. The entitled compounds with photovoltaic potential would be considered as promising materials for the development of solar energy devices.

Abstract Photoinduced intermolecular charge transfer (PICT) determines the voltage loss in bulk heterojunction (BHJ) organic photovoltaics (OPVs), and this voltage loss can be minimized by inducing efficient PICT, which requires energy‐state matching between the donor and acceptor at the BHJ interfaces. Thus, both geometrically and energetically accessible delocalized state matching at the hot energy level is crucial for achieving efficient PICT. In this study, an effective method for quantifying the hot state matching of OPVs was developed. The degree of energy‐state matching between the electron donor and acceptor at BHJ interfaces was quantified using a mismatching factor (MF) calculated from the modified optical density of the BHJ. Furthermore, the correlation between the open‐circuit voltage (Voc) of the OPV device and energy‐state matching at the BHJ interface was investigated using the calculated MF. The OPVs with small absolute MF values exhibited high Voc values. This result clearly indicates that the energy‐state matching between the donor and acceptor is crucial for achieving a high Voc in OPVs. Because the MF indicates the degree of energy‐state matching, which is a critical factor for suppressing energy loss, it can be used to estimate the Voc loss in OPVs.

In this article, a project of portable photoelectric and photo thermal devices with a power of 60W based on crystalline silicon photoelectric batteries for the production and use of electricity and hot water for household needs in the rural areas of the republic was created. This natural experiment served two purposes. The first is to determine the optimal type for the climate when the various types of PVs available in the local commercial market are used in hot climates. Second, the results of determining and comparing the changes in parameters and energy efficiency of PV and PVT with the same base and capacity at the same time under the same conditions are presented. The results of the study of the parameters that increase their effectiveness have been considered. Special attention is paid to modern components and equipment so that these devices are relatively compact and convenient to operate and control occurs easily.

The article presents the results of studying the electric and thermal efficiency of mobile photovoltaic and photothermal devices (MPVD and MPTD) based on crystalline silicon with a power of 60W panel, designed for the production of electricity and hot water for the domestic needs of rural residents. Our experiment conducted in natural conditions was carried out in the heliopolygon of the Physical-Technical Institute in July of the summer season. The device was manually adjusted and measurements were carried out in the directed mode. Reflectors are installed on the side of the photovoltaic panel (PV) in order to increase the intensity of sunlight in MPTD. As a cooling system, heat collector (HC) is installed in the back of the PV. The HC of the photothermal panel (PVT) is fundamentally different from the system of HC in other works. During the experiment carried out in natural conditions, the effects of the reflectors installed on the front surface of the photothermal device’s PV and the heat collector attached to the back side were determined. Thermal efficiency was 5.5-6 times higher than electric efficiency for PVT panels. And 90% of the solar energy falling on the surface of the photothermal device is converted into useful energy.

In March 2024 — based on computer simulation — it was reported that 2-junction 1.5 eV CdTe/0.87 eV FeSi2 solar cells can achieve actual power conversion efficiency of 43.9 %, open circuit voltage of 1.928 V, and fill factor of 89.88 % at 300 K when the cells are irradiated by the air mass 1.5 global (AM1.5G) solar spectrum [M. H. Tonmoy et al., Heliyon 10 (2024) e27994]. These simulated values exceed the ideal detailed balance-limiting power conversion efficiency, open circuit voltage, and fill factor of a 1.5 eV/0.87 eV 2-junction solar cell.

We have simulated the effect of changing the end groups in BTP core with five organic units of 1,3-Indandione (IN), 2-thioxothiazolidin-4-one (Rhodanine), propanedinitrile (Malononitrile), (2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile) (CPTCN) and 2-(3-oxo-2,3-dihydroinden-1-ylidene (IC), and two halogenated units of (4F) IC and (4Cl) IC on the optical and photovoltaic properties of the BTP DA'D core molecular unit. Thus modified, seven molecular structures are considered and their optical properties, including HOMO and LUMO energies and absorption spectra are simulated in this paper. On the basis of HOMO and LUMO energies, it is found that two of the seven molecules, BTP-IN and BTP-Rhodanine, can act as donors and the other four, BTP-(4F) IC, BTP-(4Cl) IC, BTP-CPTCN and BTP-IC, as acceptors in designing bulk heterojunction (BHJ) organic solar cells (OSCs). Using these combinations of donors and acceptors in the active layer, eight BHJ OSCs, such as BTP-IN: BTP-(4F) IC, BTP-IN: BTP-(4Cl) IC, BTP-IN: BTP-CPTCN, BTP-IN: BTP-IC, BTP-Rhodanine: BTP-(4F) IC, BTP-Rhodanine: BTP-(4Cl) IC, BTP-Rhodanine: BTP-CPTCN and BTP-Rhodanine: BTP-IC, are designed, and their photovoltaic performance is simulated. The photovoltaic parameters J s c , V o c and FF for all eight BHJ OSCs and their power conversion efficiency (PCE) are simulated. It is found that the BHJ OSC of the BTP-IN: BTP-CPTCN donor–acceptor blend gives the highest PCE (14.73%) and that of BTP-Rhodanine: BTP-(4F) IC gives the lowest PCE (12.07%). These results offer promising prospects for the fabrication of high-efficiency BHJ OSCs with the blend of both donor and acceptor based on the same core structure. [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]

BACKGROUND: Microbial desalination cell (MDC) is a new technology in the use of electrical energy for water desalination and wastewater treatment. RESULTS: Open circuit (OC) and closed circuit (CC) modes were successfully simulated with initial TDS concentrations of 10 g/L and 10–15 g/L, respectively (an external resistance of only 150 Ω was applied for CC). After 160 h of operation, the maximum OC voltage, desalination efficiency and COD removal efficiency were 809 mV, 32.2% and 79.2%, respectively. The maximum voltage was also obtained when the external resistances were 150 Ω (423.4 and 438 mV) for the initial NaCl concentrations (10 and 15 g/L) in the central chamber, respectively. Moreover, the maximal desalting and COD removal efficiencies after 24 h run‐time were (30% and 28%) and (24% and 25%) for initial NaCl concentrations (10 or 15 g/L) in the central chamber, respectively. Maintaining pH (8.61, 7.01) to (7.85, 7.8) in anode and cathode chambers was studied. This research accurately depicted microbial desalination's efficiency in generating OC voltages and CC electrical energy via Box–Behnken Design Distribution (BBD). Investigated factors' interactions (initial salt/COD concentrations, time) on CC system's energy efficiency. Resulted in peak productivity at (1.85 mW), OC reaching (1100 mV). CONCLUSION: Finally, the research paper gave exciting results in improving the efficiency of the microbial desalination cell to increase the ability to produce electrical energy and desalinate water. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has reached 26.1% in small-scale devices. However, defects at the bulk, surface, grain boundaries, and interfaces act as non-radiative recombination centers for photogenerated electron-hole pairs, limiting the open-circuit voltage and PCE below the Shockley–Queisser limit. These defect states also induce ion migration towards interfaces and contribute to intrinsic instability in PSCs, reducing the quasi-Fermi level splitting and causing anomalous hysteresis in the device. The influence of defects becomes more prominent in large-area devices, demonstrating much lower PCE than the lab-scale devices. Therefore, commercializing PSCs faces a big challenge in terms of rapid decline in working performance due to these intrinsic structural defects. This paper provides a comprehensive review of recent advances in understanding the nature and the classification of defects, their impact on voltage losses, device parameters, intrinsic stability, and defect quantification and characterization techniques. Novel defect passivation techniques such as compositional engineering, additive engineering, post-treatments, dimensionality engineering, and interlayer engineering are also reviewed, along with the improvements in PCE and stability based on these techniques for both small-area devices and large-area roll-to-roll coated devices. [ABSTRACT FROM AUTHOR]

The structural, optical, electronic and photovoltaic properties of non-fullerene molecular entity were analyzed by using density functional theory method MPW1PW91/6-31G (d, p). The simulated results of all the modeled molecules proved them as more efficient molecules for practical use in organic solar cell. Their good solution process-ability and interface (new modeled molecules: PBDBT) success made high value fill factor and open circuit voltage. Comparatively, BDCl2F-DS was proved to be an outstanding material with open-circuit voltage (1.71 eV) and fill factor (92.25%). Assumption of a similar value of short circuit current from the reference work PCE was estimated. By doing so, outstanding calculated PCE values (in the range of 27.36% to 33.76%) made newly modeled molecules an advancement in investigation of unfused non-fullerene acceptors. All the properties were studied using concepts of DFT method MPW1PW91/6-31G (d, p) and Marcus theory. The estimated LHE, free energy of electrons injection and regeneration have extraordinary values which are essential parameters for short circuit current estimation. The compatibility of donor and acceptor interfaces was proved successful by testing Voc values (in the range of 1.61 eV to 1.71 eV) with donor PBDBT. The FF was found in range of 91–92% in all designed molecules. Lastly, Power conversion efficiency of modelled molecules was estimated which was found up to 33.76%. [ABSTRACT FROM AUTHOR]

Ambarella is one of the most popular tropical fruits in Southeast Asia. Since it has a high concentration of organic acids, the fruit has the potential to be employed as an electrolyte in biobatteries. In this work, Zn-Cu biobattery electrolytes are derived from the flesh and peel of ambarella fruit. The Open- and Closed-Circuit Voltage, Maximum Power Density, and Battery Capacity of Zn-Cu Biobatteries were investigated. The OCV of the fruit's flesh was 455 mV, while the OCV of its peel was 530 mV. Given the average CCV created by ambarella peel was 471.3 mV and the average CCV generated by ambarella flesh was 342.1 mV. The highest power of Zn-Cu biobatteries was 0.27 mW when fruit flesh was used as the electrolyte and 0.22 mW when fruit peel was used as the electrolyte, Indicating a difference of 18.5%. The peel of an ambarella fruit has a battery capacity of 540 mAh, while the flesh has a capacity of 328 mAh for the Zn-Cu biobattery. This indicates that Zn-Cu with an Ambarella peel has a greater capacity but less power, urging that it be investigated prior to any prospective use. [ABSTRACT FROM AUTHOR]

The photovoltaic and optical properties of 6,6′‐dibromoindigotin (DBI) crystal under changing solvent polarity are investigated through DFT analysis. It includes geometry optimization, global reactivity, UV–vis analysis, open circuit voltage (Voc), FMOs, and NBO analysis. The highest HOMO‐LUMO gap (Egap) value is found for the gaseous phase (1.82 eV), while the lowest Egap is found for dichloro methane (1.64 eV), and intermediate values with the other solvents. The molecule has a high IP of 2.48 eV, low EA of 0.74 eV, moderate polarity, and hardness (η). The maximum absorption wavelengths (λmax) of the compound in different solvents are dichloromethane and DMSO (373 nm), chloroform (372 nm), methanol and water (371 nm), toluene (367 nm), and gaseous (356 nm). Their Voc range is 0.2–0.28 eV. Among all, chloroform demonstrates the highest performance with a fill factor (FF) of 0.8630, normalized open circuit (Nor. Voc) of 31.69 eV, and Jsc of 26.47 mA cm−2. Toluene also shows promising results with an FF of 0.8060, Nor. Voc of 19.71 eV, and Jsc of 21.19 mA cm−2. Water, although not as effective as other solvents, still exhibits respectable values with an FF of 0.8315, Nor. Voc of 23.96 eV, and Jsc of 24.63 mA cm−2. [ABSTRACT FROM AUTHOR]

Applications for Wireless Sensor Network (WSN) require cheap, highly efficient, smaller dimension Schottky-barrier (SB) solar cells. Currently, results of the SB solar cells' Open Circuit Voltage (Voc), Minority Carrier Lifetime (teff) and Power Conversion Efficiency (PCE) are discouraging. Graphene Oxide (GO) appears to be the solution because of its better surface passivation property. In this work, GO as an interfacial layer, is investigated with a simulation model and results are verified experimentally by fabrication. Novelty of this work is a change in the deposition process of GO and inclusion of an Oxide layer between the Silicon and GO. The average Voc of the proposed solar cell is increased by 4% and the minority carrier lifetime is enhanced by ~10% which is expected to increase the PCE. The noteworthy improvement of the silicon surface passivation is attributed to the dangling bond saturation which results in reduced carrier recombination. This investigation leads us to a solar cell that can be fabricated with low cost at lower thermal temperature which is a very efficient alternative to power sensor nodes that are deployed in large numbers in WSN applications. [ABSTRACT FROM AUTHOR]