Open Circuit Voltage Values Research Articles

Photovoltaic Efficiency Enhancement of Indium-Free Wide-Bandgap Chalcopyrite Solar Cells via an Aluminum-Induced Back-Surface Field Effect.

Wide-bandgap chalcopyrite materials are attractive candidates for a wide variety of energy conversion devices such as the top cell of tandem-type photovoltaic devices and photoelectrochemical water splitting hydrogen evolution devices. Nevertheless, simultaneous realization of high open circuit voltage (VOC) and high fill factor (FF) values has been challenging, and thus, the photovoltaic performance has been limited. In this article, high VOC and high FF values of wide-gap chalcopyrite CuGaSe2 thin-film solar cells are simultaneously demonstrated using an aluminum-induced back-surface field effect. An independently certified photovoltaic efficiency of 12.25% was obtained from an elemental In-free CuGaSe2:Al (bandgap energy ∼1.7 eV) solar cell (VOC: 0.959 V, short circuit current density: 17.64 mA cm-2, FF: 72.5%). In addition, an over 1 V-VOC CuGaSe2 cell (FF: 74.5%) was obtained even with the use of a conventional CdS buffer layer. Although incorporation of aluminum often leads to degradation of the chalcopyrite solar cell performance, the addition of a small amount of aluminum is found to be effective in enhancing wide-gap chalcopyrite photovoltaic performance.

Nonhalogenated Solvent-Processed Efficient Ternary All-Polymer Solar Cells Enabled by the Introduction of a Naphthyloxy Group into the Side Chain of Polymer Donors.

Conjugated polymer donors are crucial for enhancing the power conversion efficiencies (PCEs) in all-polymer solar cells (All-PSCs) in nonhalogenated solvents. In this work, three wide-band-gap polymer donors (Sil-D1, Ph-Sil-D1, and Nap-Sil-D1) based on dithienobenzothiadiazole (DTBT) and benzodithiophene (BDT) donor moieties optimized by side chain engineering were designed and synthesized. Alkyl (Sil-D1), phenyloxy (Ph-Sil-D1), and naphthyloxy (Nap-Sil-D1) alkyl siloxane side chain units were incorporated into these polymer donors, respectively. Notably, the Nap-Sil-D1 polymer donor had a greater conjugation length, π-electron delocalization, and improved dipole moment. The deepest highest occupied molecular orbital level of Nap-Sil-D1, with a high absorption coefficient, showed better aggregation properties. In addition, reduced bimolecular recombination and trap-state density generated a high charge transfer to cause a significant enhancement of open-circuit voltage, current density, and fill factor values of 0.94 V, 25.5 mA/cm2, and 70.4%, respectively, for the Nap-Sil-D1-blended All-PSC ternary device (PM6:Nap-Sil-D1:PY-IT), with the highest PCE of 16.8% in the o-xylene solvent, compared to other polymers (Sil-D1 and Ph-Sil-D1) with PCEs of 15.5 and 16.2%. As a result, this optimized device architecture was found to be the most promising as a nonhalogenated solvent processed in additive-free ternary All-PSCs with good stability.

Interface properties study of black silicon solar cells with front surface a-Si:H/c-Si heterojunction

Abstract The exceptionally low reflectance of black silicon across a broad wavelength range makes it an intriguing surface texture for solar cell applications. Silicon heterojunction (SHJ) solar cells fabricated on black silicon (Si) formed by dry reactive ion etching (RIE) using inductive coupled plasma (ICP) on n-type Si are explored. The study is focused on the properties of the a-Si:H/c-Si interface, being a key issue for the photovoltaic performance of SHJ. Deep-level transient spectroscopy (DLTS) detected no radiation defect in Si after the etching. The surface of black Si was passivated with an intrinsic a-Si:H layer, followed by the deposition of p-type and n-type a-Si:H on the front and back sides, respectively. The SHJ solar cell photovoltaic performance based on black Si is strongly influenced by defect density at the a-Si:H/Si interface. Admittance spectroscopy and effective charge carrier lifetime measurements demonstrate that interface defect density decreases with the increase of (i)a-Si:H thickness. The value of 0.75 ms effective charge carrier lifetime was reached for single (i) a-Si:H layer passivation and 0.25 ms when (p)a-Si:H was deposited over the intrinsic a-Si:H layer. The measured open circuit voltage (VOC) values for the SHJ solar cells increase with the (i)a-Si:H layer thickness reaching 658 mV. However, the fill factor decreases with increasing (i) a-Si:H layer thickness, limiting the efficiency at the maximum value below 14% due to the thickness uniformity of the a-Si:H layer. The development of conformal growth of a-Si:H is a key issue for further improvement of black Si heterojunction solar cell photovoltaic performance. 

Elucidating the Advancement in the Optoelectronics Characteristics of Benzoselenadiazole-Based A2-D-A1-D-A2-Type Nonfullerene Acceptors for Efficient Organic Solar Cells.

The potential applications of nonfullerene acceptors (NFAs) such as tunable band gaps, improved charge separation, wide-range absorption, enhanced power conversion efficiency, and operational stability make them highly favorable for organic photovoltaic applications. Herein, we designed eight novel structurally modified nonfused benzoselenadiazole (BSe)-based A2-D-A1-D-A2-type NFAs for efficient organic solar cells (OSCs). These newly modeled BSe-based NFA series contain BSe as the central core. We employed strong electron-withdrawing moieties at terminal acceptor A2 to further enhance the optical, optoelectronics, and photovoltaic characteristics of OSCs. These designed molecules (HNM1-HNM8) along with the synthetic reference molecule (HNM) were thoroughly characterized by using efficient and advanced quantum chemical simulation approaches. Thus, to ascertain the enhancement of both optical and photochemical response, a thorough density functional theory (DFT) study was carried out using the M062X level in association with the 6-31G(d,p) basis set. All of the investigated molecules (HNM1-HNM8) had their excited states calculated using the time-dependent density functional theory method. The newly designed molecules (HNM1-HNM8) presented narrower band gaps, improved absorption and optoelectronics properties, and reduced excitation and binding energies. The electrostatic potential, density of states, transition density matrix, ionization potential, and electron affinity analysis of this newly designed (HNM1-HNM8) series revealed a strong coherence with those of the reference HNM molecule. Electron density difference mapping allowed us to visualize the spatial movement of electrons between the donor and acceptor molecules during excitation. This insight helps us to understand the efficiency of charge separation and recombination processes that are critical for the performance of organic photovoltaics. The reorganization energy and charge transfer analysis suggests that HNM1-HNM8 molecules could act as NFAs for organic photovoltaic applications to enhance their efficiency further. The donor: acceptor charge transfer analysis was also carried out, which revealed that the PTB7-Th:HNM2 donor:acceptor complex shows a great charge transportation process at the donor-acceptor interface. Moreover, the photovoltaic analysis shows that the designed (HNM1-HNM8) NFA series has a great potential to produce improved open-circuit voltage and fill factor values, which may be helpful in enhancing the overall PCEs of the OSCs.

Tuning the electrochemical performance of a biphenylene coated metal as the anode for K+-ion batteries

The researchers employed density functional theory (DFT) computations to assess suitability of BP-biphenylene (b-BP) monolayers for application in potassium-ion battery systems. In their evaluations, the researchers considered various factors, like adsorption energy (Ead) of the b-BP monolayer with adsorbed potassium adatoms, in addition to diffusion energy barrier (Ebar) and storage capacity and of potassium ions on this surface. The results indicated that the b-BP monolayer has significantly higher potassium-ion storage capacities, reaching 1026 mAh/g, compared to typical graphite anodes and other carbon materials. The Ebar for potassium ions on the b-BP monolayer was determined to be 0.22 eV. Furthermore, anticipated open-circuit voltage (OCV) values for this material were found to lie within acceptable range of 0.25–1.2 V, making it suitable for use as an anode. These research findings underscore the potential of the b-BP monolayer as an appropriate anode material for potassium-ion battery (KIBs) applications.

Investigation on Lithiated Half‐Heusler Alloy CoMnSi for Lithium‐Ion Batteries

ABSTRACTIn this work, we report on CoMnSi half‐Heusler alloy as a cathode material for secondary lithium‐ion batteries using ab initio methodology based on the density functional theory. The first‐principle calculations have been performed via the Wien2k package, which utilizes the full potential linearized augmented plane wave (FP‐LAPW) method to estimate the stability of the proposed structures and electronic characteristics while considering the exchange and correlation effects within the generalized gradient approximation. This alloy is found structurally stable with better electronic properties and with the alloying of lithium (Li) into the host lattice of CoMnSi, the metallic character is attained for LixCo1−xMnSi (0.125 ≤ x ≤ 1). We propose possible reactions at electrodes during the electrochemical lithiation. The addition of Li in place of the Co atom is found to be an endothermic process. With the increase in lithium concentration, a substantial change in the total and atom projected density of states around the Fermi level is observed. The theoretical maximum specific capacity (CM) and theoretical open circuit voltage (OCV) increase with the increase of lithium concentration in CoMnSi. The CM and OCV values attain a maximum value of around 297 mAh/g and 2.4 Volts for x ≥ 0.75, which means towards the complete conversion of CoMnSi into LiMnSi. The LiMnSi exhibits a similar structure as CoMnSi, which is also advantageous for the overall performance of lithium‐ion batteries to avoid any volumetric change during the charging and discharging cycles. Hence, the proposed half‐Heusler alloys have great potential to be used as a cathode material for lithium‐ion batteries.

Cell Experiment Equipment by Using Ashes as Electrolytes

This article presents information about an experiment on how to create simple galvanic cell experiment equipment by using waste ash from burning as electrolytes, a copper plate as a cathode, and a zinc plate as an anode. The main purpose is to create a set of experimental equipment for teaching physics under the title of electrochemistry, to examine the possibility of generating electricity from ash, to study the change of the mixture ratio between the ashes and water that affects the open circuit voltage (OCV), to compare the value of the open circuit voltage from the sedimentation ashes electrolyte and non-sedimentation ashes electrolyte, and to study the pH value of the ash’s electrolyte within two hours. The research revealed that it can create five sets of galvanic cells by using different quantities of ashes, and it was found that the ashes from burning can generate electricity. The same type of ash with a different quantity will give almost the same OCV values, and changing the mixture ratio between ash and water will not affect the OCV values, which found that the mixing ratio between water and dry ash to become an electrolyte must use a minimum mixing ratio of water equal to ash or use a ratio of water more than ash to mix together. The results of measuring the value of OCV over a period of 2 hours found that the average value is almost constant, equal to 0.7 V. Here, we found that if the ash is allowed to settle, the value of OCV will decrease slightly, and if the ash is not allowed to settle, the value of OCV is constantly unchanged. It was also found that the pH value of the ash in each galvanic cell during the period of 2 hours was the same, with an average high alkalinity of about 13. This shows that alkaline electrolytes can generate electricity and have almost constant electricity. These five devices can be applied as a teaching tool for the Physics and Chemistry subject in the title of electrochemistry for students at the secondary school level and bachelor’s students because of an easy way to fabricate galvanic cells. The materials used are cheap and easy to find. It can also be used to study the characteristics of electrical conductivity in ash’s electrolyte and the characteristics of ash’s electrolyte.

Functionalized MBene, Ti[formula omitted]BX[formula omitted] (X=Si, Ge, P, As) as potential excellent anode materials for lithium and sodium-ion batteries: A first-principles study

In the search for next-generation energy storage devices, superior-performance alternative electrode materials based on two-dimensional materials for rechargeable metal-ion batteries are essential. Here, we explored group III and IV functionalization of 2D Ti2B, Ti2BX2 (X=Si, Ge, P, As) as anode materials for Li and Na ion batteries using first-principles calculations. The structures had excellent metallic properties and demonstrated energetically favorable adsorptions for metal ions. Analyzing charge transfer and electronic band structures, silicon and phosphorous-functionalized Ti2B (Ti2BSi2 and Ti2BP2) showed the most potential. The energy band diagrams showed that both Ti2BSi2 and Ti2BP2 had metallic characteristics after Li and Na-ion adsorption, which offered considerable advantage for rechargeable-ion batteries. The structures exhibited low energy barriers for Li and Na-ion migration. The minimum energy barriers calculated for Na were 0.08 eV for Ti2BSi2 and 0.24 eV for Ti2BP2. Theoretical specific capacity and open circuit voltage were calculated using maximum layer adsorption. For both Li and Na, high values of specific capacity and low values of open circuit voltage (¡ 1 V) were found. Ti2BSi2 had the best performance, with a theoretical specific capacity of 1647.10 and 1317.68 mA h/g for Li and Na, respectively. Its open circuit voltages for Li and Na were 0.65 and 0.38 V. The insights of this study will be beneficial in fabricating high-performing Ti2BX2-based anodes for rechargeable Li and Na ion batteries.

Impact of calcined temperatures on the crystalline parameters, morphological, energy band gap, electrochemical, antimicrobial, antioxidant, and hemolysis behavior of nanocrystalline tin oxide

To construct a battery, the precipitation-synthesized SnO2 products at 450 °C and 650 °C were separately taken and mixed with graphite as the anode and PbO2,V2O5, and graphite materials as cathode materials to make the pellets and examine their open circuit voltage (OCV) values. The microstrain, lattice parameter, and crystallite size values of the above-mentioned tin oxide compounds were obtained through Rietveld refinement-MAUD fit analysis. The microstrain and lattice parameter values of tin oxide were significantly varied at a higher calcined temperature. Surface particle grain growth was increased with the increased calcined temperature from 450 to 650 °C as evidenced by FE-SEM study. Particle size distributions of SnO2 and polycrystalline behavior have been discussed with the aid of TEM analysis. From the UV–visible spectra, optical band gap (Eg) values reduced from 3.73 to 3.69 eV for the SnO2 products with an increase in calcined temperatures from 450 to 650 °C. The antimicrobial responses of the two different calcined SnO2 samples at 450 °C and 650 °C against two different bacterial pathogens (gram-positive-S. aureus and gram-negative-E.coli) were investigated. From the microbicidal assessment, a relatively higher diameter of the zone of inhibition (DZOI) of tin oxide at 650 °C samples was measured to be 19 ± 2 mm and 21 ± 2 mm for S. aureus and E. Coli than the DZOI of SnO2 at 450 °C samples (15 ± 1 mm for S. aureus and 18 ± 1 mm for E. coli. DPPH scavenging activity at 100 μg/ml shows that SnO₂ calcined at 450 °C achieves 68 ± 1 %, while SnO2 calcined at 650 °C exhibits a significantly higher activity of 86 ± 1 %. A slight increase in hemolysis was observed for SnO2 calcined at 650 °C, reaching 1.3 % at higher concentrations, but overall, hemolysis remained below 5 %, indicating high hemocompatibility.

Fabrication, photovoltaic analysis, and electrical characterization of Au/ZnTPyP/p-Si/Ag heterojunction under gamma radiation effect for solar cell applications

The main objective of the current study is to investigate the impact of gamma rays on the characteristics and behavior of a fabricated heterojunction device based on tetra pyridyl-porphine zinc (ZnTPyP). The importance of this study includes determining critical parameters such as conversion efficiency (η). A cobalt-60 gamma source has been employed to investigate the effects of gamma exposure dosages ranging from 0 to 5 kGy on the morphological and optical features of the studied material. An atomic force microscope (AFM) was used to examine the morphological characteristics of the ZnTPyP film that formed on the glass substrate. The thin film’s optical characteristics were investigated on quartz for both as-deposited and irradiated films at various gamma doses (1 kGy and 3 kGy). Additionally, ZnTPyP is evaporated on p-type silicon substrates to create ZnTPyP/p-Si heterojunction. The current–voltage (I–V) curves at various doses of gamma radiation at 0, 1, 3, and 5 kGy for Au/ ZnTPyP /p-Si/Ag heterojunction device are experimentally measured. The predominant conduction processes are the thermionic emission and single-trap space-charge-limited current (SCLC). Furthermore, the values of the barrier height φB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\varphi_{B} } \\right)$$\\end{document} are estimated using two different methods, including I–V method and Norde’s equations at different doses, and their values are comparable. Under illumination at 0 kGy, we found the values of short-circuit current (Isc), open-circuit voltage (Voc), and photoconversion efficiency (η) to be 0.92 mA, 0.41 V, and 4.28%, respectively. On the hand, some important optical parameters are determined for both as-deposited and irradiated ZnTPyP films, such as skin depth (δ), and found that δ values reduce with increasing gamma doses, reflecting the efficiency and performance of photovoltaic cells. Finally, the study indicated the alteration in the studied optical parameters and slightly enhanced the Au/ZnTPyP/p-Si/Ag heterojunction efficiency when subjected to gamma radiation.

Cu2+ ions implanted porous titania for efficient dye sensitized solar cells

In the quest to unlock the remarkable potential of nanotechnology, the sol-gel method was employed to craft a porous TiO2 nanostructured film, meticulously deposited onto FTO glass substrates. This endeavor marked a significant leap as a controlled bombardment of Cu ions, accelerated at 700 keV, at varying flux rates of 2x1013, 2x1014, and 2x1015 ions/cm² was introduced to these ingeniously engineered films. A comprehensive assessment of these nanocrystalline TiO2 structures, both before and after Cu+2 ion irradiation, revealed a fascinating array of results. he anatase tetragonal structure's permanence was validated by X-ray diffraction (XRD), which improved the material's stability and integrity. In the present study, an interesting observation was made that band edges show a dynamic behavior in Cuirradiated samples in UV-Vis spectroscopy. At 2x1014 ions/cm2, the phenomena peaked, revealing an intriguing redshift and an exceptionally low band gap value of 3.39 eV. In photoluminescence spectra, the peaks corresponding to the lattice defects show a significant reduction when the flux of the Cu ions on TiO2 is adjusted to 2 x 1014 ions/cm2. It is an indication that film quality and purity have improved. This arrangement for photoanode modification helps in the development of dye-sensitized solar cells with tremendous characteristics. The fabricated device with this novel approach results in high values of open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and maximum photoconversion efficiency of 5.10%. These findings indicate a new era of possibilities in the field of renewable energy, since these nanostructured materials have the ability to significantly alter the solar field.

Self-regulating heating and self-powered flexible fiber fabrics at low temperature

Self-regulating heating and self-powered flexibility are pivotal for future wearable devices. However, the low energy-conversion rate of wearable devices at low temperatures limits their application in plateaus and other environments. This study introduces an azopolymer with remarkable semicrystallinity and reversible photoinduced solid-liquid transition ability that is obtained through copolymerization of azobenzene (Azo) monomers and styrene. A composite of one such copolymer with an Azo: styrene molar ratio of 9:1 (copolymer is denoted as PAzo9:1-co-polystyrene (PS)) and nylon fabrics (NFs) is prepared (composite is denoted as PAzo9:1-co-PS@NF). PAzo9:1-co-PS@NF exhibits hydrophobicity and high wear resistance. Moreover, it shows good responsiveness (0.624 s−1) during isomerization under solid ultraviolet (UV) light (365 nm) with an energy density of 70.6 kJ kg−1. In addition, the open-circuit voltage, short-circuit current and quantity values of PAzo9:1-co-PS@NF exhibit small variations in a temperature range of -20 °C to 25 °C and remain at 170 V, 5 μA, and 62 nC, respectively. Notably, the involved NFs were cut and sewn into gloves to be worn on a human hand model. When the model was exposed to both UV radiation and friction, the temperature of the finger coated with PAzo9:1-co-PS was approximately 6.0°C higher than that of the other parts. Therefore, developing triboelectric nanogenerators based on the in situ photothermal cycles of Azo in wearable devices is important to develop low-temperature self-regulating heating and self-powered flexible devices for extreme environments.

Synthesis, Crystal Structure, and Theoretical Screening of Solvatochromism and Light-Harvesting Performance of Hexamine V-Substituted Lindqvist-Based Photosensitizer for Photovoltaic Solar Cells.

In this paper, we employ density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches to predict the solvatochromism and light-harvesting properties of a newly synthesized hybrid hexamine (HMTA) vanadium-substituted Lindqvist-type (V 2 W 4 ) polyoxometalate (POM), (C7H15N4O)2(C6H13N4)2[V2W4O19]·6H2O, (HMTA-V 2 W 4 ) for application in dye-sensitized solar cells (DSSCs). Single crystal X-ray diffraction (XRD) and noncovalent interaction (NCI) analyses show a 3D-supramolecular packing stabilized by means of hydrogen bonds and van der Waals (vdW) and ionic interactions between highly nucleophilic cage-like HMTA surfactant, lattice water, and electrophilic V 2 W 4 polyanions. Experimental and theoretical UV/vis absorption spectra show large absorption in the visible region, which is strongly solvent polarity dependent. This solvatochromic behavior can be attributed to hydrogen bonding interactions between the V 2 W 4 polyanion and protic solvents. Furthermore, the energy level of semiconductor-like nature of HMTA-V 2 W 4 with high LUMO level matches well with the conduction band (CB) of TiO2, which is beneficial for the photovoltaic device performance. The photovoltaic empirical parameters are theoretically predicted to demonstrate a remarkably high open-circuit voltage (Voc) value (1.805 eV) and a photoelectric conversion efficiency (PCE) value up to 8.7% (FF = 0.88) along with superior light-harvesting efficiency (LHE) (0.7921), and therefore, the studied compound is expected to be a potential candidate as a photosensitizer dye for applications in DSSCs. The aim of this work was to broaden the range of applications of POMs, owing to their low-cost fabrication, leveraging and flourishing optoelectronic properties, and ever-improving efficiency and stability for use in future technology pointed to the development of clean and green renewable energy sources to solve the current energy crisis.

Inorganic salts released from polypyrrole nanocapsules on compact TiO2 layer for highly efficient inorganic CsPbI3-type perovskite solar cells

The compact TiO2 serves as a crucial electron transport layer (ETL) for fabricating high-efficiency CsPbI3 solar cells. Modifying TiO2 with inorganic ions is regarded as a simple and effective method to optimize the band energy level, eliminate interface defects, and enhance the crystallinity of the CsPbI3 film. However, inorganic ions risk being washed away by perovskite solvents such as DMF and DMSO. In this work, core–shell inorganic salt (LiCl, NaCl, ZnCl2)@polypyrrole nanocapsules (PPy NCPs) were fabricated as a buffer layer at the interface of TiO2/CsPbI3 layer. The inorganic salts are released from PPy NCPs during the annealing process of the CsPbI3 precursor film, thereby preventing them from being washed away by the DMF/DMSO solvents. Compared to NaCl@PPy NCPs-TiO2, ZnCl2@PPy NCPs-TiO2, and pristine TiO2 films, the LiCl@PPy NCPs-TiO2 exhibited the best electron conductivity and highest Fermi level. The released LiCl not only passivates point defects in TiO2 by forming Li-O-Ti bonds, optimizing the energy level at the TiO2/perovskite interface, but also incorporates into the CsPbI3 lattice, improving its crystallinity. As a result, solar cells based on LiCl@PPy NCPs-TiO2 layer demonstrated a higher PCE of 19.78 %, along with increased open-circuit voltage (VOC) and fill factor (FF) values of 1.161 V and 83.1 %, respectively. Furthermore, the LiCl@PPy NCPs-TiO2 layer also enhanced the stability of CsPbI3 solar cells under humidity conditions.

Optimizing perovskite solar cell efficiency with Cs0.15FA0.81MA0.04PbBr0.14I2.86 - MAPbBr3 QDs Complex active layer and GuBr interface modified layer

Achieving optimal efficiency in perovskite solar cells (PSCs) necessitates the creation of a light-absorbing layer with superior crystallization, minimal defect concentration, exceptional stability and better energy level alignment. In this context, the active layer of the PSCs comprises (Cs0.15FA0.81MA0.04PbBr0.14I2.86), incorporating MAPbBr3 quantum dots doped with toluene as an anti-solvent to enhance device performance, achieving a Photovoltaic Conversion Efficiency (PCE) of 18.9 %. Furthermore, GuBr is introduced at the interface between NiOx and photovoltaic active layer for effective interface modification. These improvements lead to optimized devices, particularly with GuBr modification at doping amount of 3 mg/ml, showcasing an impressive PCE of 20.6 %. Noteworthy attributes of these devices include a short-circuit current density of 24.7 mA/cm2 and an open-circuit voltage (Voc) value of 1.02 V. Significantly, the altered film retained more than 81 % of its original effectiveness for a prolonged duration surpassing 10 days. The conclusive findings underscore the successful attainment of high efficiency and high stability through the employed design strategy in PSCs.

Numerical Expedition on the Potential of AgBiS2-Based Thin Film Solar Cells Employing Different Carrier Transport Layers.

In this study, a photovoltaic (PV) device has been developed by using AgBiS2 as the key material. The simulation of the photovoltaic cell has been performed using the SCAPS-1D simulator to analyze the impact of each layer. The design incorporates three window layers, CdS, In2S3, and ZnSe, alongside six familiar compounds, AlSb, CuGaSe2 (CGS), CuS, MoS2, Sb2S3, and WSe2, as the back surface field (BSF) layers. These heterostructures aim to uncover the potential of AgBiS2 in the realm of photovoltaic technology. When AgBiS2 functions within a singular heterojunction, specifically in configurations such as n-CdS/p-AgBiS2, n-In2S3/p-AgBiS2, and n-ZnSe/p-AgBiS2, the resulting values for open-circuit voltage (V OC) and the short circuit current (J SC) are found to be ∼0.90 V and ∼32 mA/cm2, respectively, while the corresponding power conversion efficiencies (PCE) are 23.56%, 22.60%, and 23.62%, respectively. On the contrary, the incorporation of various BSF layers like AlSb, CGS, CuS, MoS2, Sb2S3, and WSe2 results in a substantial increase in V OC, leading to an enhancement in PCE. Among the AgBiS2 based different dual-heterostructures, the outstanding PCE of 30.04% with a V OC of 1.12 V is achieved by n-ZnSe/p-AgBiS2/p+-Sb2S3 device. In comparison, the n-ZnSe/p-AgBiS2/p+-CGS structure exhibits a similar PCE of 30.03% with a V OC of 1.12 V. Additionally, the n-ZnSe/p-AgBiS2/p+-MoS2 arrangement demonstrates a PCE of 29.95% and a V OC of 1.12 V. The effective band alignments observed at the interfaces of ZnSe/AgBiS2 and AgBiS2/MoS2, ZnSe/AgBiS2 and AgBiS2/CGS, as well as ZnSe/AgBiS2 and AgBiS2/Sb2S3 contribute to a substantial built-in potential, leading to an elevated V OC. As an alternative to ZnSe, the CdS window could offer similar performances, whereas In2S3 might provide a lower efficiency. The elaborate simulation findings highlight the substantial potential of AgBiS2 as an absorber, particularly when coupled with different windows and BSF layers. This opens avenues for experimental research focused on AgBiS2 in the era of photovoltaic cells.

Transparent metal-oxide photovoltaics for energy harvesting and storage for sustainable platforms

A transparent photovoltaic (TPV) energy harvesting method would provide more degrees of freedom for deployment on windows, buildings, vehicles, and surfaces with less soil dependency. This study designs a TPV-integrated energy storage system (capacitor charger) as a sustainable energy platform. The TPV device comprises a metal-oxide junction with a thin Si layer to enhance light utilization across a broad spectrum. Wide-bandgap metal-oxide-based materials absorb high-energy ultraviolet (UV) photons, while the Si layer captures longer wavelength lights due to the lower bandgap. The TPV structure (FTO/NiO/p+-Si/a-Si/n+-Si/AZO/ITO) exhibits an average visible transparency of 37 % and a power conversion efficiency of 4.97 % under 405 nm UV light illumination. The excellent electrical characteristics with a short-circuit current density of 10.1 mA/cm2 and open-circuit voltage value of 0.79 V allow TPVs to serve as a power source for rapidly charging capacitor banks in the energy storage unit. This PV-linked capacitor energy system can illuminate LED lamps, suggesting an on-site sustainable energy platform. The proposed Si-embedded TPV demonstrates electric power generation across broad wavelengths, enabling the bi-directional PV utilization of sunlight and indoor light sources for energy harvesting both day and night.

Chlorination of benzyl group on the terminal unit of A2-A1-D-A1-A2 type nonfullerene acceptor for high-voltage organic solar cells

Benzotriazole (BTA)-based A2-A1-D-A1-A2 type wide-bandgap (WBG) non-fullerene acceptors (NFAs) have shown promising potential in indoor photovoltaic, and in-depth investigation of their structure-property relationship is of great significance. Herein, we explored the chlorination effect of the side chain on the terminals. We introduced Cl atoms into the benzyl side chains in parent BTA5 to synthesize two NFAs, BTA5-Cl with mono-chlorinated benzyl groups and BTA5-2Cl containing bi-chlorinated benzyl groups. We chose D18-Cl with deep-energy levels and strong crystallinity to pair with these three acceptors, affording high photovoltage and photocurrent. With the stepwise chlorination, the open-circuit voltage (VOC) values decrease from 1.28, 1.22, to 1.20 V, while the corresponding power conversion efficiencies (PCEs) improve from 5.07 %, 9.15 %, to 10.96 %. Compared with BTA5-based OSCs, introducing Cl atoms downshifts the energy levels and slightly increases the non-radiative energy loss (0.14 < 0.17 < 0.19 eV), resulting in a sequential decrease in VOC. However, more chlorine atom replacements produce more effective exciton dissociation, higher charge transfer, and balanced carrier mobility in the blend films, ultimately achieving better PCEs. This work indicates that chlorination of the benzyl group on the terminals can improve the device's performance, implying good application potential in indoor photovoltaics.

Light management in hole transport layer-free perovskite solar cell by SPP and LSPR

In recent years, light management based on localized surface plasmon resonance (LSPR) effects in perovskite solar cells (PSCs) has received significant attention. However, the use of surface plasmon polariton (SPP) excitations in PSCs has been less studied. Meanwhile, hole transport layer-free perovskite solar cells (HTL-free PSCs) have garnered interest due to their lower cost. In this study, we improve light absorption in HTL-free PSCs by simultaneously utilizing LSPR and SPP effects. Au nanotriangles are employed on the surface of the back electrode to excite SPPs. The thickness of the perovskite layer is varied from 100 nm to 400 nm. The optimal periodicity and dimensions of the triangular nanoparticles are determined for each perovskite layer thickness. In the optimal structures with perovskite layer thicknesses of 100 nm, 200 nm, 300 nm, and 400 nm, absorption enhancements of 25%, 12.4%, 13%, and 4.3% are achieved, respectively. The interaction of light with SPP and LSP modes leads to improved solar cell performance. Furthermore, the short circuit current density (JSC) in structures with layer thicknesses of 100 nm and 200 nm increased from 16.7 mA cm−2 to 20.71 mA cm−2 and from 19.8 mA cm−2 to 21.86 mA cm−2, respectively. Other photovoltaic characteristics of the solar cell were obtained through optical-electrical numerical analysis. For the improved solar cell with a perovskite thickness of 100 nm, the values of open circuit voltage, efficiency, and fill factor were 0.847 V, 0.81, and 14.24%, respectively, representing increases of 1.1%, 2.4%, and 28.7% compared to the bare device. Additionally, in the solar cell with a thickness of 200 nm, an efficiency of 17.03% was achieved, showing a 12.5% improvement compared to the bare structure. Our research results facilitate the design of high-performance, ultra-thin, semi-transparent solar cells.

Synthesis and characteristics of densified GDC-LSO composite as a new apatite-based electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFC)

Developing solid-state ionic conductors with desirable charge-transport efficiency and reasonable durability is a fundamental and long-lasting challenge for solid-oxide fuel cells (SOFCs). Ceria-based electrolytes, as one of the most common types of electrolytes for intermediate-temperature solid-oxide fuel cells (IT-SOFCs), offer a high surface-exchange coefficient and faster kinetics in the triple phase boundaries (TPBs); however, they suffer to some extent of electronic conductivity in the reducing atmosphere and gradual phase transitions. Here in this work, we have reported a novel co-doped IT-SOFC electrolyte composite combining the apatite structure of Lanthanum Silicate (LSO) with the fluorite structure of Gadolinium-doped Ceria (GDC), which showed a high ionic conductivity and a minimal electronic leak. The resulting GDC-LSO composite electrolyte also achieved an OCV (open-circuit voltage) of 1 V at 800 °C, implying a significant improvement in the OCV values reported for the typical ceria-based electrolytes (∼0.75 V). The sample was prepared using 40 wt% GDC and 60 wt% LSO (40GDC-60LSO) showed a maximum electrical conductivity of 25 mS cm−1 at 800 °C with good densification properties (>95 % relative density). The cell electrochemical performance measurement was conducted using a 3.0 vol% humified H2 stream at the anode side while the cathode side was exposed to the air at 800 °C. The interdiffusion of cations between La3+ in the LSO phase and Ce4+ and Gd3+ in the GDC phase was detected by XRD and EDX results after sintering samples at 1500 °C for 4 h using 0.5 wt% PVA or 0.5 wt% Ethyl cellulose (EC) as the binder. The proposed GDC-LSO composite could help better understand the influence of compositional constituents and processing variables on the densification and electrical properties of the electrolyte materials for the IT-SOFCs.