Photovoltaic Applications Research Articles

Solvent-mediated carboxylic acid diammonium spacer for synthesizing FA-based 2D Dion–Jacobson perovskites toward efficient solar cells

Two-dimensional (2D) perovskites are promising for photovoltaic applications due to their outstanding optical properties and better environmental stability compared to three-dimensional (3D) perovskites. Unlike 2D Ruddlesden–Popper (RP) perovskites, which use monovalent ammonium spacers, Dion–Jacobson (DJ) perovskites employ divalent organic spacers that enhance structural stability by mitigating weak van der Waals interactions. However, the random phase distribution and disorder crystal orientation in 2D DJ perovskites create deep quantum wells, hindering charge transfer and reducing short-circuit current density (JSC) and overall photovoltaic performance. This study introduces an organic diammonium, 1,4-butanediamine diacetate (BDAAc2), to replace the traditional halide spacer 1,4-butanediamine iodide (BDADI2). This substitution regulates perovskites crystallization dynamics, reducing compositional disorder and random phase distribution, thus improving the quality of the perovskite films. The robust coordination interactions between BDAAc2 and the perovskite inorganic framework lead to an ordered [PbX6]4− arrangement, suppressing the formation of complex intermediate phases and significantly enhancing δ phase crystallinity in the intermediate film. This results in a high yield of high-quality α phase. Consequently, the resulting 2D DJ perovskite solar cells based on BDAFA3Pb4(I0.9Br0.1)13 achieve a higher power conversion efficiency of 16.41% and an elevated JSC of 20.46 mA cm−2.

Compositionally Tunable Magneto-optical Properties of Lead-Free Halide Perovskite Nanocrystals.

Inorganic lead-free metal halide perovskites have garnered much attention as low-toxicity alternatives to lead halide perovskites for luminescence and photovoltaic applications. However, the electronic structure and properties of these materials, including the composition dependence of the band structure, spin-orbit coupling, and Zeeman effects, remain poorly understood. Here, we investigated vacancy-ordered Cs3Bi2X9 (X= Cl, Br) perovskite nanocrystals using magnetic circular dichroism spectroscopy. Our results indicate that the excitonic spectra are predominantly composed of direct and indirect band gap transitions and that the Zeeman splitting energy of the direct exciton increases from 0.50 to 0.63 meV at 7 T by substituting Br for Cl. Comparison with analogous results for Cs2AgBiCl6 nanocrystals, obtained by cation substitution, suggests an important effect of charge distribution within electronic bands on the excitonic Zeeman splitting. This work demonstrates that the magneto-optical properties of these materials can be effectively manipulated via chemical composition, suggesting promising applications in photonics, spintronics, and optoelectronics.

Photovoltaic and Piezoelectric Power Generation Characteristics of Flexible Poly(Vinylidene Fluoride‐Ran‐Trifluoroethylene) Thin Films

ABSTRACTWe investigated the photovoltaic and piezoelectric power generation characteristics of ferroelectric poly(vinylidene fluoride‐ran‐trifluoroethylene, PVDF‐TrFE) thin films on flexible indium tin oxide (ITO)/polyethylene terephthalate (PET) substrates. The solar cells and piezoelectric hybrid devices provide consistent energy to extend battery life and improve self‐charging. The flexible PVDF‐TrFE thin films with a transmittance of about 60% in the visible region showed a remanent polarization of about 10.5 μC/cm2 (2Pr ~ 21.0 μC/cm2) with excellent β‐phase formation. The flexible PVDF‐TrFE thin films exhibited optimal ferroelectric and piezoelectric properties by exhibiting β‐phase without α‐phase. Since β‐phase is the phase that carries high dipole alignment of the material, which is important for maximizing power output, the performance of the material in photovoltaic and piezoelectric applications is enhanced. The PVDF‐TrFE capacitor exhibited not only a piezoelectric generation characteristic with an approximate voltage of 1.1 V under compression, but also a photovoltaic generation feature with an open‐circuit voltage of about 0.23 V and a short‐circuit current of approximately 0.13 mA/cm2.

A q‐Z Source‐Based Modified Bidirectional Three‐Port Converter for Battery‐Assisted Solar PV Applications

ABSTRACTIn this paper, two separate q‐Z source‐based three‐port converters (TPC) with modified bidirectional networks (BDNs) that offer significant voltage gain for photovoltaic (PV)‐battery applications are proposed. Both designs allow the converter operation to be carried out in four different modes where the power from primary source can flow to the battery as well as the load and the battery alone can also feed power to the load, at lower duty cycle. The designs are based on a q‐Z source converter and use a modified bidirectional path to accommodate the battery port. The main advantage of using one of the two proposed topology is that it provides a common ground for the primary source input (PV), the bidirectional energy storage port, and the output port. In addition to the above mentioned four modes of operation, in the proposed topology, an external switch can be used to charge the battery from the PV source in the absence of the load as well. On the basis of these two distinct advantages, one of the two designs is analyzed in detail. A noncomplex control algorithm is designed to facilitate the battery operation depending upon load power requirement. There are two different duty ratios to control the operation of five MOSFETs to regulate the output voltage. In addition, the converter offers suitable features such as low voltage stress (V) across devices, continuous input current, and common ground (comm.g.) for all three ports, to be used for renewable energy source (RES) applications. The validation of the analytical analysis of the converter is done in a Matlab simulink environment, and the results are presented. For validating the performance of the proposed converter, a 250‐V, 450‐W prototype is implemented and tested at 10 kHz. The converter in stand‐alone mode can attain an efficiency of around 94.5%.

Nanopore Confinement Effect Mediated Heterogeneous Plasmonic Metasurfaces for Multifunctional Biosensing Interfaces.

Plasmonic metasurfaces (PMs) exhibit extraordinary optical response due to surface lattice resonance, which is crucial for realizing high-performance photovoltaic device preparation. In this work, a nanopore confinement effect-mediated MOF@UsAu is proposed as a novel PM heterojunction for photovoltaic interfaces. 2D MOFs have the unique advantage of a tunable and ordered porous structure. Its nanopore confinement effect regulates in situ synthesis of AuNPs on the MOF surface in dimensions and regions. The interface delocalization induced by work function matching and the Schottky barrier formed by band bending enhance the ordered LSPR and photovoltaic response of PM heterojunctions, achieving a significant enhancement of SPR interface plasma electric field. Based on the bi-directional interaction design between the S-shaped multifunctional peptide and MOF@UsAu, a PMs-enhanced SPR biosensor is constructed for direct, real-time, and ultrasensitive analysis of tumor exosomes. This study is the first to use 2D MOFs as substrates for constructing PMs and designing customized in situ synthesis strategies for specific application scenarios. It provides new ideas for the design of novel PMs and the construction of customized photovoltaic interfaces, expected to be extended to various types of photovoltaic device applications.

A computational exploration of structural, electronic, and optical properties of Hf- substituted CaZr1-x HfxS3 (x = 0.25, 0.50, and 0.75) for photovoltaic applications

Abstract This study investigates the structural, electronic, and optical properties of Hf-substituted CaZrS₃ (CaZr_(1-x) Hf_x S_3, where x =0.25,0.50, and 0.75) for photovoltaic applications. Using first-principles calculations within the Quantum Espresso framework, we explore the effects of Hf incorporation on the orthorhombic crystal structure (Pnma space group). The study reveals that Hf substitution significantly influences the material’s properties, including lattice parameters, band gap, and optical absorption. The calculated band gaps for Hf-substituted CaZrS₃ are smaller than the experimental value for unsubstituted CaZrS₃, indicating enhanced suitability for photovoltaic applications. Moreover, Hf substitution improves the thermal, mechanical, and chemical stability of the material. The results suggest that Hf-substituted CaZrS₃ is a promising candidate for high-efficiency, stable, and environmentally friendly photovoltaic devices.

Creation of Flexible Heterogeneously-Doped Carbon Nanotube Paper PN Diodes to Enhance Thermoelectric and Photovoltaic Effects

This study investigates the fabrication and characterization of flexible PN diode devices using phosphorus- and boron-doped carbon nanotube (CNT) paper, also known as Buckypaper (BP). The BP substrate is fabricated from multi-walled carbon nanotubes (MWCNTs) and doped with phosphorus and boron to form N-type and P-type semiconductors, respectively. Various experimental techniques, including Raman spectroscopy, Hall effect measurements, and scanning electron microscopy (SEM), are employed to analyze the properties of the doped BP. The results reveal that the current-voltage (I-V) and capacitance-voltage (C-V) characteristics preliminarily exhibit the basic electrical properties of a diode after doping with P-type and N-type carriers. Subsequently, optimized vertical stacking combined with parallel electrode configurations for the BP diode devices demonstrates that vertical series stacking gradually enhances the thermoelectric voltage, while horizontal parallel connections approximately scale up the thermoelectric and photovoltaic voltages proportionally. The findings underscore the critical role of creating heterogeneously doped CNT-paper PN junction electric fields in improving the performance of carbon-based semiconductor devices. Furthermore, we demonstrate that these directionally oriented energy devices, when stacked, can form modular systems with enhanced efficiency. This work highlights the potential of flexible carbon material-based devices for advanced thermoelectric and photovoltaic applications.

Regulating Strain and Suppressing Defect States Through Polymer Ionization and Chemical Chelation for Efficient Inverted Flexible Perovskite Solar Cells.

Flexible perovskite solar cells (FPSCs) have great promise for applications in wearable technology and space photovoltaics. However, the unpredictable crystallization of perovskite on flexible substrates results in significantly lower efficiency and mechanical durability than industry standards. A strategy is investigated employing the polymer electrolyte poly(allylamine hydrochloride) (PAH) to regulate crystallization and passivate defect states in perovskite films on flexible substrates. The weakly acidic precursor allows PAH to undergo partial ionization, leading to the protonation of some ─NH3 + groups into ─NH3 +. Simulations and experimental results indicate that multifunctional PAH forms strong chemical interactions with precursors of perovskite materials including Formamidine Hydroiodide (FAI) and Lead Iodide (PbI2), facilitating homogenous nucleation and growth of crystals of perovskite films. High-resolution transmission electron microscopy (HR-TEM) reveals that PAH strongly anchors to grain boundaries (GBs), consistent with findings from photo-induced force microscopy-based infrared spectroscopy (PiFM-IR). PAH improves the uniformity distribution of Young's modulus between the grains and GBs, facilitating stress relief in the perovskite films. Therefore, the champion efficiency of PAH-modified FPSCs reaches 24.19% and exhibits strong bending durability, retaining 87.9% of their initial efficiency after 2500 bending cycles (r = 5 mm), demonstrating their practical application potential in outdoor wearable electronic products.

Vacuum-Nitrogen Assisted (VANS) Topotactical Deintercalation for Extremely Fast Production of Functionalized Silicene Nanosheets.

Silicene, the analog of graphene composed of silicon atoms arranged in a honeycomb lattice, has garnered significant attention due to its unique properties, positioning it as a promising candidate for various applications in electronic devices, photovoltaics, photocatalysis, and biomedicals. While the chemical synthesis of silicene nanosheets has traditionally involved time-spending and expensive- methods, this study introduces a rapid vacuum/nitrogen cycle assisted (VANS) protocol that dramatically speeds up the production of silicene. The strategic implementation of vacuum/nitrogen cycles provides the efficient removal of the generated hydrogen, boosting the overall reaction kinetics while maintaining inert reaction conditions to prevent oxidation. In contrast to previous methodologies, usually qualified by prolonged reaction durations of up to 5 days and low reaction temperatures (-30°C), this integrated approach substantially shortens the synthesis time from hours to minutes. Indeed, the VANS method drastically reduces the reaction time, operates at room temperature, and exhibits the successful fabrication of silicene flakes with structural properties comparable to those achieved through prolonged reaction times and low temperatures.

Iron-irradiated methylammonium lead iodide bromide (MAPbI2Br) thin films with enhanced optical and electrical properties for high-efficiency perovskite solar cells

In the pursuit of enhancing the optoelectronic properties of perovskite thin films for photovoltaic applications, this study investigates the effects of Fe ion irradiation on methylammonium lead iodide bromide (MAPbI₂Br) thin films. Thin films of methylammonium lead iodide bromide, (CH3NH3PbI2Br, or MAPbI2Br) have been deposited by sol–gel dip coating technique. These films were irradiated with 300 keV Fe ions with flouncy of 2 × 1014 ions/cm2. The prepared films all show the cubic crystal structure. However, the film irradiated with Fe ions has a larger grain size, according to XRD. The optical characteristics, such as refractive index, band gap energy, and extinction coefficients, are examined by UV–Vis analysis. Although both the films showed a direct bandgap, the film irradiated with Fe ions showed a lower value for the bandgap energy (1.76 eV) and high refractive index. The device structure used was FTO/TiO2/MAPbI2Br/spiro-OMeTAD/Au. The devices made with 300 keV Fe ions irradiated film has high current density of 10.86 mA cm−2, fill factor of 0.80, an open circuit voltage of 1.06 V, and an efficiency of 9.93%. The findings emphasize the potential of Fe ion irradiation as a novel technique to improve grain structure and optoelectronic properties, advancing perovskite-based device technology for higher efficiency solar cells.

Enabling Ultrafast Intramolecular Singlet Fission in Perylene Diimide Tetramer with Saddle-Shaped Linker.

Intramolecular singlet fission (SF) in multichromophore systems is of high interest for photovoltaic application. As an attractive candidate for SF-based devices, enabling efficient SF in covalent oligomers of perylene diimide (PDI) still remains challenging. In this work, inter-PDI SF with τSF = ∼150 ps and ∼150% triplet yield in a covalent tetramer COTh-FPDI was facilitated by employing a saddle-shaped cyclooctatetrathiophene (COTh) core and fused linking with PDIs. In comparison, ultrafast symmetry-breaking charge separation (τCS = ∼100 fs) was observed for the tetramer COTh-αPDI with flexible linking. Taking advantage of rigid linking and minimized excited-state structural relaxation, unique inter-PDI geometry in COTh-FPDI can be fully defined by the topological characteristic of COTh, which plays a key role for inter-PDI electronic coupling required by SF. Our work provides a new strategy for enabling intramolecular SF by predefining interchromophore geometry by a rigid structure, which might be inspired for future designing of multichromophore SF systems.

A comparative study of the structural, electronic, and optical properties of Ca3SbCl3 halide perovskite using DFT-GGA and HSE06 functional for photovoltaic applications

A comparative study of the structural, electronic, and optical properties of Ca3SbCl3 halide perovskite using DFT-GGA and HSE06 functional for photovoltaic applications

Fabrication of Black Silicon Antireflection Coatings to Enhance Light Harvesting in Photovoltaics

Black silicon has attracted significant interest for various engineering applications, including solar cells, due to its ability to create highly absorbent surfaces or interfaces for light. It enhances light absorption in crystalline solar cells, improving the efficiency of converting incident light into electricity for photovoltaic applications. This research focused on fabricating nanostructures that played a critical role in enhancing light absorption in the upper layers of solar cells. These nanostructures were created using the black silicon method, forming a layer known as “black silicon”. The coating not only improved the efficiency of crystalline solar cells but also enhanced their stability. The antireflection coating, composed of nanostructures with various shapes, including conical, pillar-like, and spike-like forms, achieved a reflectivity as low as 10% in the spectral range of 400–700 nm. This corresponded to a sample with α = 0.85 and a chuck bias of 4 W. An Inductively Coupled Plasma Reactive Ion Etching (ICP RIE) machine was employed to develop and control the specific shape, size, and density of the fabricated black silicon, which was then subjected to testing. The efficiency of the black silicon photovoltaic cell was 23.3%.

Multistage Regulation Strategy via Fluorine-Rich Small Molecules for Realizing High-Performance Perovskite Solar Cells.

Perovskite solar cells (PSCs) are an ideal candidate for next-generation photovoltaic applications but face many challenges for their wider application, including uncontrolled fast crystallization, trap-assisted nonradiative recombination, and inefficient charge transport. Herein, a multistage regulation (MSR) strategy for addressing these challenges is proposed via the introduction of fluorine-rich small molecules with multiple active points (i.e., 1-[Bis(trifluoromethanesulfonyl)methyl]- 2,3,4,5,6-pentafluorobenzene (TFSP)) into the precursor solution of the perovskite film. The addition of TFSP effectively delays and regulates the crystallization and growth process of the perovskite film for larger grains and fewer defects, and it effectively improves the coverage of self-assembled molecules for efficient charge transport. The multiple active points of TFSP induce a strong binding affinity with uncoordinated defects in the perovskite film. Moreover, the high fluorine content of TFSP induces strong electronegativity to establish a high binding strength between the perovskite film and electron transport layer. Finally, PSCs prepared by the MSR strategy demonstrated an optimal power conversion efficiency (PCE) of 25.46% and maintained 91.16% of the initial PCE under nonpackaged air conditions and at a relative humidity of 45% after 3000h.

Sliding Mode Control and Immersion & Invariance Observer for Grid-Tied Inverters in Photovoltaic Applications: Continuous Operation for Power Quality Enhancement

This work proposes a model-based control scheme using a sliding mode controller (SMC) and an immersion and invariant (I&I) observer. The objective of the proposed control scheme is to be applied to a three-phase grid-tied inverter, which could operate as a shunt active power filter when the photovoltaic array is not generating power (night-time operation). The grid-tied inverter always remains operational, ensuring continuous support of the power quality improvement, as well as current harmonic compensation due to nonlinear loads and power factor correction. An external control loop is included to keep the voltage of the DC-link capacitor regulated. As can be explained in detail along with the work, a battery stack is avoided in this proposed research. Thus, a decision stage is added to the control scheme to select the night or day operation. Simulation results are carried out using Altair-PSIM© to demonstrate the effectiveness of the proposed control scheme in several scenarios.

High-Temperature Mechanical Properties of Basalt Fibers: A Step Towards Fire-Safe Materials for Photovoltaic Applications

Amidst the urban energy transition towards clean and renewable energy, distributed photovoltaic (PV) systems are emerging as critical infrastructure. However, the evolution of PV rack and mount systems has lagged, particularly in addressing cost efficiency and fire safety This study focuses on the high-temperature mechanical properties of basalt fibers (BFs), a key component of basalt fiber-reinforced polymer (BFRP), to establish a foundational understanding for future BFRP applications. The experimental results demonstrate that basalt fibers retain approximately 150 MPa residual tensile strength at 600 °C (30–40% of room temperature strength of Q235B steel) and 94 MPa at 800 °C, outperforming steel under similar conditions. Furthermore, the decomposition of wetting agents and Fe2+ oxidation at 600 °C was observed to stabilize after 100 min, maintaining structural integrity. These findings validate the high-temperature performance of BF, paving the way for subsequent studies at the BFRP composite level, which will address structural optimization and fire-resistance strategies for PV rack and mount systems. This research provides a critical step toward improving the safety and sustainability of urban PV systems.

Colossal Shift Currents in Band-Inverted Bi Nanotubes Driven by the Interplay of Curvature and Spin-Orbit Coupling.

The concept of non-trivial electronic structure combined with reduced dimensionality presents a promising strategy for advancing optical applications and energy harvesting technologies. Symmetry breaking in low dimensional system enables the emergence of non-linear optical responses, which are greatly amplified by the singular points of band inversion. Here, using first-principles calculations, the significant enhancement of the shift current in Bi nanotubes is investigated, driven by the combined effects of 1D geometry and non-trivial band order. By rolling a 2D Bi monolayer, which exhibits a quantum spin Hall phase, into a 1D nanotube, an extraordinarily large shift current of 4.94 A·Å2V-2 is generated, two orders of magnitude larger than the experimental values in WS2 nanotubes. The enhancement of the shift current in Bi nanotubes is demonstrated and attributed to the state mixing induced by the interplay of strong spin-orbit coupling, the curvature of the tube, and the non-trivial band order of Bi nanotubes. The robustness of this enhanced shift current against various perturbations is also discussed, such as oxidation and doping. The novel approach integrating non-trivial band order with reduced dimensionality sheds new light on advanced photovoltaic applications by harnessing both geometric advantages and exotic electronic structures for energy conversion.

Fine Tuning the Glass Transition Temperature and Crystallinity by Varying the Thiophene-Quinoxaline Copolymer Composition.

In recent years, the design and synthesis of high-performing conjugated materials for the application in organic photovoltaics (OPVs) have achieved lab-scale devices with high power conversion efficiency. However, most of the high-performing materials are still synthesised using complex multistep procedures, resulting in high cost. For the upscaling of OPVs, it is also important to focus on conjugated polymers that can be made via fewer simple synthetic steps. Therefore, an easily synthesised amorphous thiophene-quinoxaline donor polymer, TQ1, has attracted our attention. An analogue, TQ-EH that has the same polymer backbone as TQ1 but with short branched side-chains, was previously reported as a donor polymer with increased crystallinity. We have synthesised copolymers with varied ratios between octyloxy and branched (2-ethylhexyl)oxy-substituted quinoxaline units having the same polymer backbone, with the aim to control the aggregation/crystallisation behaviour of the resulting copolymers. The optical properties, glass transition temperatures and degree of crystallinity of the new copolymers were systematically examined in relation to their copolymer composition, revealing that the composition can be used to fine-tune these properties of conjugated polymers. In addition, multiple sub-Tg transitions were found from some of the polymers, which are not commonly or clearly seen in other conjugated polymers. The new copolymers were tested in photovoltaic devices with a fullerene derivative as the acceptor, achieving slightly higher performances compared to the homopolymers. This work demonstrates that side-chain modification by copolymerisation can fine-tune the properties of conjugated polymers without requiring complex organic synthesis, thereby expanding the number of easily synthesised polymers for future upscaling of OPVs.

Ultrathin transparent indium tin oxide-based electrodes for enhanced performance of perovskite solar cells

Abstract Perovskite solar cells (PSCs) have been given much attention in photovoltaics-based power generation, particularly in building integrated photovoltaics (BIPV) applications due to their lightweight and promising technical performance. PSCs exhibit remarkable transparency to visible light, which makes them an ideal candidate for BIPV applications such as glass-based solar facades and clear solar windows. As the PSC is yet an immature technology, much research is still required to validate its visibility and cost-effectiveness for different applications including electrical vehicles. This paper takes one step forward in achieving this goal by presenting a new ultrathin transparent electrodes (UTE) design that comprises a square patch layout to improve the performance of transparent conductive materials. The proposed electrode design is aimed to improve the absorption of the material in the ultra-violet (UV) region with high optical transparency. To assess the angular dependence on the absorption characteristics, both transverse magnetic and transverse electric modes are studied at various oblique angles of incident light. Furthermore, interference theory is applied numerically to validate the proposed UTE design. The impact of various geometric parameters including period, ground height, spacer height, and top square resonator length on the performance of the proposed UTE layout is investigated through detailed simulation analysis. Moreover, surface electric field patterns are analyzed to understand the absorption mechanism of the proposed UTE. Results reveal the effectiveness of the proposed structure for various BIPV applications including electric vehicles, wearable electronics, and tandem devices.

Exploring the physical characteristics of chalcogenide SrZrS3 perovskite: Insights for photovoltaic use

AbstractIn this study, first-principle-based Density functional Theory (DFT) have been utilized to investigate the electronic, optical, mechanical and thermal properties of SrZrS3 for the solar cell application. Semiconducting nature of SrZrS3 was found via the investigation of electronic band structure and density of state (DOS). Electronic band structures reveal direct bandgap semiconductor properties with values 0.57 eV in Perdew-Burke-Ernzerhof functional (PBE) method, and 1.28 eV is in hybrid Functional (HSE06) method for SrZrS3, suggesting specific applications in photovoltaic (PV) cell. Significant constant such as absorption, reflectivity, refractivity, and loss function were also calculated to evaluate the optical properties of SrZrS3. The optical properties highlight the potential of SrZrS3 material for optoelectronic and photovoltaic applications. The Born stability criteria confirmed the mechanical stability of this compound. Furthermore, its minimum thermal conductivity (Kmin = 0.66 Wm−1 K−1) is adequate for maintaining performance without excessive heat buildup, making it suitable for high-efficiency solar cells. Graphical Abstract