Search Results (637)

Modern photovoltaic technologies are increasingly evaluated not only in terms of power conversion efficiency and cost, but also with respect to resource origin, toxicity, recyclability, and overall life-cycle impacts. Within this broader sustainability framework, bio-based and bio-inspired materials derived from biomass or mimicking biological structures have emerged as promising candidates for a wide range of photovoltaic components, including active layers, interfacial modifiers, substrates, encapsulants, and natural dyes. This review provides a layer-by-layer overview of such materials implemented or proposed in dye-sensitized, organic, perovskite, biohybrid, and silicon solar cells, linking their molecular structures and optoelectronic properties to representative device performances and key degradation pathways. Cross-cutting challenges related to moisture and thermal stability, barrier performance, feedstock variability, and the risk of “greenwashing” are highlighted, emphasizing that sustainability claims must be supported by quantitative metrics such as life-cycle assessment, circularity indicators, and durability studies. Finally, we outline promising research directions in molecular engineering, hybrid biosynthetic architectures, and advanced encapsulation concepts that could enable bio-based materials to make a meaningful contribution to low-impact photovoltaic technologies. Full article

Dye-sensitized solar cells (DSSCs) represent a promising photovoltaic technology for indoor and building-integrated applications due to their colour tunability, semi-transparency, and favourable spectral response. However, the sustainability of conventional devices is hindered by the use of volatile organic solvent-based electrolytes, which raise concerns regarding toxicity, flammability, and long-term stability. This review analyses the evolution of DSSC architecture, with particular focus on electrolyte media, ranging from aqueous systems to deep eutectic solvents and bio-derived quasi-solid architectures. Special attention is focused on the interplay between electrolyte composition, dye design, and interfacial charge-transfer processes. By highlighting recent progress and remaining challenges, this work outlines viable strategies toward safe, durable, and fully sustainable DSSCs tailored for indoor and integrated photovoltaic applications. Full article

The production of sustainable and cost-effective energy remains a global challenge, with photovoltaic technology emerging as a promising solution. Sensitizers play a key role in electron production in dye-sensitized solar cells, which are emerging photovoltaic devices; thus, different chemical structures have been introduced to achieve the best results. Determining the optimal conditions for the coating and application of dye materials to obtain optimal efficiency and performance is of great importance. For this purpose, an organometallic dye was used to extract the optimal coating conditions. Two factors—ambient temperature during photoanode preparation and anti-aggregation agent concentration—were selected as effective parameters, and the optimal conditions for achieving high efficiency and durability were determined using machine learning. Finally, the findings were analyzed from two perspectives: the preparation of laboratory devices using the selected dye and the evaluation of similar dye materials to validate the proposed optimal conditions. Full article

In this study, we investigated how co-solvent and polymer combinations affect the performance of dye-sensitized solar cells (DSSCs) using TiO₂- and ZnO-modified carbon nanotube (CNT) composite papers as photoelectrodes. Co-solvents such as N,N-dimethylformamide (DMF) and ethylene glycol (EG) were incorporated into polyethylene glycol (PEG)- and poly(ethylene oxide) (PEO)-based gel electrolytes to increase the amount of dissolved I₂/KI redox species and evaluate their influence on the wettability of the electrolyte on CNT composite paper electrodes. PEG-based electrolytes containing DMF or EG improved the fill factor (FF) and power conversion efficiency (PCE) relative to the baseline formulation, with the EG–PEG electrolyte achieving the best single-device PCE of 15.58 × 10⁻³% using the CNT/ZnO composite paper. Replacing PEG with PEO or using PEG + PEO blends led to reduced performance, possibly because the modified polymer composition affected electrolyte wetting, spreading behavior, and penetration into the porous electrode. These results suggest that the wettability and viscosity-related behavior of gel electrolytes are important empirical factors associated with the performance of flexible paper DSSCs, and provide practical guidance for the design of paper-based photovoltaic devices. Full article

This work demonstrated improvements in the photovoltaic performance metrics of a dye-sensitized solar cell (DSSC) through the application of Eu-doped strontium silicate (Sr₂SiO₄:Eu³⁺), a luminescent downshifting (LDS) material. The material converted underutilized high-energy ultraviolet (UV) photons into lower-energy visible photons for better spectral responsivity in the DSSC. A conventional solid-state technique was applied in the synthesis of the material. Surface morphology was examined by scanning electron microscopy (SEM). Photoluminescence (PL) measurements were conducted to analyze fluorescence emission. The photovoltaic performances of the bare and LDS-enhanced devices were analyzed using photovoltaic current–voltage measurements. Compared to the bare DSSC, the cell containing Sr₂SiO₄:Eu³⁺ LDS phosphor material had an enhancement of 14.8% in the short-circuit current density (J_sc), from 0.243–0.279 mA/cm². The open-circuit voltage (V_oc) yielded an improvement of 10% from 580–638 mV. Maximum power output (P_max) produced a boost of 26.5% from 0.0136–0.0172 mW and the efficiency improvement at 26.6% from 1.09–1.38%. The coefficient of variation was introduced to evaluate device reproducibility. The device with the incorporation of Sr₂SiO₄:Eu³⁺ LDS phosphor depicted a coefficient of variation of 8.5%, suggesting good DSSC reproducibility. Full article

This study demonstrated luminescence decay dynamics of BaSiO₃:Eu²⁺, elucidating its potential as a spectral converting down-shifting material for improving the performance of dye-sensitized solar cells (DSSCs). Time-resolved photoluminescent (TRPL) measurements under excitation pulses of a picosecond pulsed light-emitting diode (EPLED) revealed complex decay dynamics described by a triple-exponential model. Average lifetime was in nanoseconds, which facilitated rapid emission of down-shifted photons, essential to mitigating reabsorption losses. The presence of a fast decay channel is crucial to minimizing photon reabsorption and maximizing the flux of visible photons transferred to the dye molecules of DSSCs to enhance photocurrent generation. Full article

Photovoltaic technologies represent an increasingly relevant alternative for developing renewable energy sources, particularly those based on light-harvesting materials such as perovskite solar cells (PSCs) and dye-sensitized solar cells (DSSCs), which have achieved efficiencies of 27.3% and 13.0%, respectively. In this context, phenothiazine (PTZ) has attracted considerable interest as a structural block due to its outstanding structural and photophysical properties, which also represent low production costs and reduced environmental impact. This review presents recent advances in the design and development of phenothiazine-based organic materials for photovoltaic applications, analyzing the main synthetic routes for obtaining this nucleus, as well as the fundamental aspects related to the operation of solar cells, including relevant device parameters. Furthermore, several studies focused on the synthesis, characterization, and performance of new phenothiazine-derived molecules used in photovoltaic devices are also examined. Finally, the most relevant conclusions are discussed, and future perspectives for the use of these materials in solar technologies are proposed. Full article

Dye-sensitized solar cells (DSSCs) remain attractive as low-cost photovoltaic devices; however, their practical efficiency is still constrained by electron-transport losses, interfacial recombination, and incomplete light harvesting in conventional titanium dioxide (TiO₂) photoanodes. The effects of TiO₂ film thickness, multi-walled carbon nanotube (MWCNT) incorporation, and multilayer oxide interface engineering on DSSC performance were examined. Degussa P25-TiO₂ photoanodes were first optimized with respect to thickness, after which controlled MWCNT loadings and sequential compact sol–gel TiO₂ and tin dioxide (SnO₂) sublayers were introduced. The optimum pristine P25-TiO₂ photoanode thickness was 9.11 μm, yielding an open-circuit voltage of 0.74 ± 0.01 V, a short-circuit current density of 14.10 ± 0.40 mA/cm², a fill factor of 56.24 ± 1.00%, and a power-conversion efficiency of 5.93 ± 0.20%. The incorporation of 0.025 wt% MWCNTs increased the efficiency to 6.04 ± 0.20%, corresponding to an absolute gain of 0.11 percentage points. The best performance was obtained with the sol–gel SnO₂/sol–gel TiO₂/P25-CNT multilayer photoanode, which delivered 0.74 ± 0.02 V, 16.22 ± 0.40 mA/cm², 57.59 ± 1.00%, and 6.89 ± 0.30%, respectively. FE-SEM, EIS, XRD, Heated Ultrasonic Cleaner and UV–visible analyses indicate that the multilayer architecture preserves porosity, enhances light harvesting, and suppresses interfacial recombination, while the CNT network facilitates charge transport. Full article

Using electrochemical impedance spectroscopy (EIS), a technique that analyzes the electrical response of a system subjected to a sinusoidal disturbance in order to probe its physicochemical properties, this study determined an optimal molar ratio of 1:7 between ethylene glycol (EG) and potassium iodide (KI). This composition significantly improves the electrochemical performance of the KI, EG, and I₂ electrolyte for photovoltaic applications. Four formulations with KI:EG molar ratios of 1:5, 1:7, 1:9, and 1:11 were synthesized. The amount of diiodine (I₂) was fixed at 0.1 mol% relative to the amount of KI. These electrolytes were then characterized by EIS. The series resistance (Rs), charge transfer resistance (Rct), diffusion resistance (Rw), CPE (constant phase element) parameter, and exponent (n) were extracted and compared. The results show that the formulation with KI:EG = 1:7 has the lowest Rct (3.054 Ω) and Rw (7.296 Ω) values, indicating optimal redox kinetics and improved ion transport within the electrolyte. This molar ratio corresponds to a minimum Rs value (5.612 Ω), indicating reduced series resistance. The mechanisms of solvation, viscosity, and ion diffusion are examined. This work, based exclusively on screening by electrochemical impedance spectroscopy (EIS), highlights the decisive role of solvent composition in electrolyte performance. It identifies an optimal molar ratio window that strikes a balance between redox efficiency and ion mobility, with a view to improving DSSC performance. Full article

Two Zn(II) coordination compounds based on glaucine-derived Schiff bases were synthesized and investigated as potential materials for dye-sensitized solar cells (DSSCs). The structures of all compounds were established by X-ray diffraction analysis and quantum chemical modeling (DFT/TD-DFT). Their photophysical properties (absorption and luminescence spectra in solution and the solid state), electrochemical characteristics, and photovoltaic parameters in DSSC devices were studied. The highest power conversion efficiency (PCE ~5.18%) was demonstrated by the free ligands, which is attributed to their favorable absorption spectrum and optimal alignment of energy levels relative to the conduction band of TiO₂ and the redox couple of the electrolyte. The Zn(II) coordination compounds exhibited significantly lower efficiency (~2.1%). Impedance spectroscopy results indicated more efficient charge transfer at the TiO₂/dye/electrolyte interface for the organic derivatives. Full article

Dye-sensitized solar cells (DSCs) have garnered significant attention due to their high power conversion efficiency and low production cost-effectiveness. In this study, we developed a hierarchically structured three-layer TiO₂ photoanode via hydrothermal synthesis to significantly enhance DSC performance. The optimized device achieved a short-circuit current density of 16.92 mA/cm² and a photoelectric conversion efficiency of 8.34%, representing improvements of 15.67% and 20.5%, respectively, compared to traditional DSCs with a single-layer TiO₂ photoanode in our study. The significance lies in the rational design principle rather than absolute efficiency. This performance enhancement stems from the complementary functions of each architectural layer: (1) a bottom layer of TiO₂ nanocrystals providing high surface area for dye adsorption, (2) an intermediate layer of vertically aligned TiO₂ nanorods enabling efficient electron transport, and (3) a top layer of TiO₂ microspheres simultaneously boosting dye loading and light harvesting through enhanced light scattering. Our findings demonstrate that rational design of multi-layered photoanode architectures can effectively address the competing demands of surface area, charge transport, and light management in high-performance DSCs. Full article

The chlorophyll molecule is considered a low-cost material, easy to synthesize, and easily extracted from plant leaves. It exhibits high chemical stability, structural flexibility, and high absorbance ability at the visible range of electromagnetic radiation. In this work, the geometrical, electronic, and optical properties of pure, dissolved, and doped chlorophyll (C1) natural organic dye were computed by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The solvents considered include water (H₂O), acetone (C₂H₆O), dichloromethane (CH₂Cl₂), chloroform (CH₃Cl), and dimethyl-sulfoxide (DMSO) (C₂H₆OS). The solar photovoltaic parameters, such as light-harvesting efficiency (LHE), oscillation strength (f), free energy of electron injection (${\Delta \mathrm{G}}_{\mathrm{I}\mathrm{n}\mathrm{j}.}$) and regeneration (${\Delta \mathrm{G}}_{\mathrm{R}\mathrm{e}\mathrm{g}.}$), open-circuit voltaic (V_OC), and efficiency ($\eta$), were also investigated. The evaluated energy gap slightly shifted from 1.920 eV to 1.980 eV based on the solvent polarity, while the UV-Visible absorption spectrum red-shifted from 422.3 nm to 439.8 nm, improving the overall efficiency up to 21.5% in DMSO solvent. The (LHE) and (${\Delta \mathrm{G}}_{\mathrm{I}\mathrm{n}\mathrm{j}.}$) properties regarding Cl molecules improved up to 69.1% and −1.384 eV when dissolved in chloroform and DMSO solvents, respectively. Doping C1 molecule via metal transition atoms such as zinc (Zn), nickel (Ni) and copper (Cu) further modified the optical and photovoltaic performance. Doped C1 molecule via Cu atom shows the best photonic results, including the highest open-circuit voltage (V_oc) and conversion efficiency ($\mathrm{Ƞ}$), while the Ni-doped C1 dye displays the longest lifetime, 1.699 µs, and the highest electronic coupling constant, 1.975 eV; thus, it has the superior photovoltaic performance. These results demonstrate that both solvents and transition metal atom modification significantly improve C1 performance, making metal-doped C1 a promising low-cost and eco-friendly sensitizer for dye-sensitized solar cells (DSSCs). Full article

Dye-sensitized solar cells (DSSCs) represent a promising low-cost photovoltaic technology with relatively high conversion efficiency and a simple fabrication process. Natural dyes have drawn growing interest compared to ruthenium-based dyes since they are greener. However, the power conversion efficiency (PCE) of natural dyes is generally low. In this study, we investigated novel approaches to improve the PCE of DSSCs using Delonix regia extracts by polarity-based separation using preparative thin-layer chromatography (PTLC). Our study indicated that polarity-based separation can significantly enhance the PCE, with one fraction achieving a PCE of 1.13%, which is high compared to most natural dye-based DSSCs, and is also 1.85 times that of the crude methanol extract. The major compounds in the highest-efficiency layer were flavanol-based dyes. Our study demonstrates the potential antagonistic effects within Delonix regia extracts in DSSC applications, which play a critical role in improving PCE. The study is expected to support future efforts to enhance the PCE of natural compound-based DSSCs, especially those using flavanol-based natural dyes. Full article

This paper presents paper-based dye-sensitized solar cells (paper DSSCs) fabricated using carbon nanotube (CNT) composite paper produced from mixtures of CNT and pulp dispersions. DSSC is composed of a dye-adsorbed semiconducting electrode, a counter electrode, and an electrolyte. In this study, our DSSC is constructed using n-type semiconducting CNT composite paper as the semiconducting electrode, metallic CNT composite paper as the counter electrode, and ordinary paper for keeping the electrolyte. In our previous study, potassium hydroxide was used to convert semiconducting CNT composite paper to n-type, but the performance was limited. Therefore, we aim to achieve a more stable and higher-performing paper DSSC by annealing the semiconducting CNT composite paper in a hydrogen–argon atmosphere to induce n-type properties. For this, CNT composite paper was prepared using the cationic surfactants DODMAC( dimethyl octadecyl ammonium=chloride, cationic surfactant) and DDAC as dispersing agents. The fabricated DSSCs were evaluated in terms of photoelectric conversion efficiency and fill factor (FF). As a result, DSSCs using DODMAC increased the efficiency from 5.04 × 10⁻³% to 13.37 × 10⁻³% and the FF from 0.13 to 0.21. When DDAC was used, the efficiency increased to 17.11 × 10⁻³% and the FF improved to 0.27. Full article

Iron(II) complexes bearing N-heterocyclic carbene (NHC) ligands have emerged as promising earth-abundant dye sensitizers for applications in dye-sensitized solar cells (DSSCs). In this work, we present a computational study of a set of 42 Fe–NHC dyes derived from seven ligand frameworks, systematically functionalized with donor, acceptor, and donor–acceptor groups to tune or enhance their photophysical properties. The calculated geometries reveal that substitution modulates Fe–N bond lengths and ligand dihedral angles only slightly, preserving the structural integrity of the complexes. TD-DFT calculations show clear and predictable electronic trends: donor groups raise the HOMO, acceptor groups lower the LUMO, and the combined push–pull configuration produces the most pronounced HOMO–LUMO gap narrowing and largest redshifts in MLCT transitions. Key DSSC performance descriptors, including electron-injection and dye-regeneration free energies, light-harvesting efficiency, excited-state lifetimes, and hole-transport reorganization energies, collectively identify the double-acceptor and push–pull derivatives as the most promising candidates across multiple frameworks. Full article