Search Results (74)

Building-integrated photovoltaics (BIPVs) can benefit not only from transparent but also from opaque modules that maximize light capture. We present haze-assisted luminescent solar concentrators (HALSCs) that integrate scattering and luminescence in multilayer designs. Polymer–liquid crystal composites with embedded dyes form micron-scale domains that act as broadband Mie scattering centers, while the dye provides spectral conversion. Monte Carlo ray-tracing simulations and experiments reveal that edge-emitted intensity increases with haze thickness but saturates beyond a threshold; segmenting the same thickness into multiple thinner layers enables repeated scattering, markedly enhancing side-guided emission. When coupled with crystalline silicon solar cells, multilayer HALSCs converted this optical advantage into enhanced photocurrent, with triple-layer devices nearly doubling output relative to transparent controls. These findings establish opacity–luminescence coupling and multilayer haze engineering as effective design principles, positioning HALSCs as practical platforms for advanced BIPVs and optical energy-management systems. Full article

This study investigates the synthesis and characterization of boron-modified nanotubular titania (NTO) arrays fabricated via a single-step anodizing process with varying concentrations of boric acid (BA). Following anodization, a reductive heat treatment was applied to facilitate the crystallization of the anatase phase in the boron-modified NTO. The effect of the BA concentration on the structural, morphological, and photoelectrochemical (PEC) properties of the NTOs was systematically explored through scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), luminescence, and UV-Vis spectrometry. The introduction of boron during anodization facilitated the formation of sub-bandgap states, thereby enhancing the light absorption and electron mobility. This study revealed the optimal BA concentration that yielded a 3.3-fold enhancement of the PEC performance, attributed to a reduction in the bandgap energy. Notably, the highest incident photon-to-current conversion efficiency (IPCE) was observed for NTO samples anodized at a 0.10 M BA concentration. These findings underscore the promise of boron-modified NTOs for advanced photocatalytic applications, particularly in solar-driven water-splitting processes. Full article

In the context of rapid decarbonization, photovoltaics (PV) has played a key role. Traditionally, PV installations require large land areas, leading to competition between PV and agriculture for land use. This conflict must be addressed as the demand for both energy and food continues to rise. Additionally, it poses broader challenges, potentially leading local communities to perceive PV energy production as a threat to their economic activities and food security. An emerging and promising solution is agrivoltaics (AV), a combination of agriculture and PV. AV comes in many different forms, ranging from the simple coexistence of crops and PV installations on the same patch of land to a full synergy of the two, producing better crops while also harvesting energy from the sun. This paper paints a complete picture of the scientific work produced so far throughout the field, with special attention to the use of third-generation PV and luminescent solar concentrators (LSCs). Both technologies minimize shading and enable wavelength selection and enrichment (when functionalized with fluorescent materials) to better align with the photosynthetic needs of plants. The viability of AV has also been evaluated from an economic standpoint. This work aims to assess the current landscape of AV research and to point out possible future developments. It also seeks to evaluate whether the advantages of semi-transparent devices are substantial enough to justify their development and employment on a scale comparable to traditional PV. Full article

Long-term reliability is crucial for the commercialization of semi-transparent photovoltaic panels based on Luminescent Solar Concentrators (LSCs). This study addresses key challenges such as photodegradation and hail resistance using glazed LSC prototypes functionalized with organic Lumogen F dyes. A pilot-scale batch of LSC prototypes (10 × 10 cm²) underwent extensive outdoor exposure tests following the IEC 62108 “10.15 Outdoor Exposure Test” to evaluate long-term stability under natural solar radiation. Continuous monitoring revealed that prototypes with Lumogen F Red 305 experienced a 29% efficiency drop initially, which stabilized over time, indicating potential long-term stability. In contrast, those with Lumogen F Violet 570 showed minimal degradation, with only a 9% efficiency reduction. Additionally, the hail resistance of LSC panels was tested using the IEC 62108 “10.9 Hail Impact Test”. Panels with varying glass thickness, tempering methods, and surface areas were subjected to impact from 25 mm hailstones launched at 22.4 ± 5% m/s. All samples remained undamaged, highlighting their excellent hail resistance, a critical feature for preserving performance despite potential surface damage. This study demonstrates that combining glazed lightguides with polyvinyl butyral improves photostability and provides a cost-effective alternative to expensive fluorophores, while ensuring compliance with hail resistance standards. Full article

This research addresses the need for enhanced thermal management in building-integrated photovoltaic systems, specifically focusing on semi-transparent PV panels based on luminescent solar concentrator (LSC) technology. In pursuit of optimal thermal regulation, the cooling effect of a paraffin PCM was investigated via finite element simulations developed with COMSOL Multiphysics. The PCM was thermally coupled with the PV cells situated in the frame of a south-facing window. Due to the seasonal difference between winter and summer, the PCM latent heat capacity and melting temperature were optimized to ensure the maximum nominal operating cell temperature (NOCT) reduction during summer months. PCM latent heat capacities equivalent to 120 kJ/kg, 180 kJ/kg, and 240 kJ/kg have been investigated, whereas for the melting temperature a range from 20 °C to 42 °C was spanned. The combination of higher latent heat and 36 °C melting point showed the most significant thermal benefits, by reducing the NOCT from 42 °C to 36 °C, which led to an 11.80% increase in power output across the whole PV window. Considering the same latent heat, the other melting temperature resulted in more moderate benefits, namely an enhancement of 7.88% and 3.94%, for 38 °C and 40 °C, respectively. The lower latent heat capacities resulted in an NOCT reduction that ranged between 2.7 °C and 5.3 °C, according to the associated melting point. These results testify that the presented solution could significantly enhance energy production in semi-transparent PV applications based on LSC panels. Full article

Building-integrated photovoltaic (BIPV) glazing systems with intelligent window technologies enhance building energy efficiency by generating electricity and managing daylighting. This study explores advanced BIPV glazing, focusing on building-integrated concentrating photovoltaic (BICPV) systems. BICPV integrates concentrating optics, such as holographic films, luminescent solar concentrators (LSC), Fresnel lenses, and compound parabolic concentrators (CPCs), with photovoltaic cells. Notable results include achieving 17.9% electrical efficiency using cylindrical holographic optical elements and crystalline silicon cells at a 3.5× concentration ratio. Dielectric CPCs showed 97.7% angular acceptance efficiency in simulations and 94.4% experimentally, increasing short-circuit current and maximum power by 87.0% and 96.6%, respectively, across 0° to 85° incidence angles. Thermochromic hydrogels and thermotropic smart glazing systems demonstrated significant HVAC energy savings. Large-area 1 m² PNIPAm-based thermotropic window outperformed conventional double glazing in Singapore. The thermotropic parallel slat transparent insulation material (TT PS-TIM) improved energy efficiency by up to 21.5% compared to double glazing in climates like London and Rome. Emerging dynamic glazing technologies combine BIPV with smart functions, balancing transparency and efficiency. Photothermally controlled methylammonium lead iodide PV windows achieved 68% visible light transmission, 11.3% power conversion efficiency, and quick switching in under 3 min. Polymer-dispersed liquid crystal smart windows provided 41–68% visible transmission with self-powered operation. Full article

Quantum-cutting luminescent solar concentrators (QC-LSCs) have great potential to serve as large-area solar windows. These QC nanocrystals can realize a photoluminescence quantum yield (PLQY) of as high as 200% with virtually zero self-absorption loss. Based on our previous work, we have constructed a Monte Carlo simulation model that is suitable to simulate the performance of the QC-LSCs, which can take into account the band-edge emissions and near-infrared emissions of the QC-materials. Under ideal PLQY conditions, CsPbCl_xBr_3−x:Yb³⁺-based LSCs can reach 12% of the size-independent external quantum efficiency (η_ext). Even if LSCs have a certain scattering factor, the CsPbCl_xBr_3−x:Yb³⁺-based LSCs can still obtain an η_ext exceeding 6% in the window size (>1 m²). The flux gain (FG) of the CsPbCl_xBr_3−x:Yb³⁺-based LSC-PV system can reach 14 in the window size, which is a very encouraging result. Full article

[Eu(³DPIQC)₃] (where DPIQC = 3-(diphenyl phosphoryl)-1-isoquinolinecarboxylate), a luminescent europium complex with antenna ligands, has been carefully embedded within a polyvinyl butyral (PVB) matrix and the resulting material was used to prepare films used as luminescent down-shifting layers (LDSLs) for crystalline Si-based solar cells. The films were characterized using photoluminescence spectroscopy, atomic force spectroscopy (AFM), UV-Vis spectroscopy, and fluorescence microscopy. The AFM analysis shows films with low surface roughness, while fluorescence microscopy revealed that the Eu complex embedded in PVB assumed a spheroidal configuration, a morphology especially beneficial for optical applications. The so-obtained LDSLs were utilized as energy converters in c-Si solar cells to enhance the utilization of high-energy photons, thereby improving their overall efficiency. The determination of photovoltaic parameters carried out before and after the deposition of the LDSLs on the c-Si cells confirms a positive effect on the efficiency of the cell. The J_sc increases from 121.6 mA/cm² to 124.9 mA/cm², and the open circuit voltage (V_oc) is found to be unrelated to the complex concentration in the films. The fill factor (FF) remains constant with the Eu concentration. The EQE curves indicate an enhancement in the performance of the photovoltaic cells within the UV region of the spectrum for all coated devices. Electrochemical impedance spectroscopy (EIS) was also carried out in order to analyze the effect of the Eu complex in the charge transfer process of the devices. Full article

In this study, we aim to minimize light loss and achieve high power conversion efficiencies (PCE) in perovskite solar cells (PSCs) by employing a spectral conversion film component with antireflection properties. In our scheme, NaYF₄:Tm, Yb, and Gd luminescent nanorod/silica nanosphere-based thin films are applied on CH₃NH₃PbI₃ PSCs to improve the device efficiency. The film was fabricated by spin coating an aged silica sol containing NaYF₄:Tm, Yb, and Gd luminescent nanorods. The size and the spectral conversion properties of the NaYF₄:Tm, Yb, and Gd luminescent nanorods were controlled by tuning the Gd³⁺ ion concentration. The microstructure and the transmittance properties of the thin film were controlled by changing the concentration of NaYF₄:Tm, Yb, and Gd luminescent nanorod in silica sol. The thin films have excellent spectral conversion properties while exhibiting a maximum transmittance. The photovoltaic performance of PSCs with NaYF₄:Tm, Yb, and Gd luminescent nanorod/silica nanosphere-based thin films was systematically investigated. The light transmittance was optimized to 95.1% on a cleaned glass substrate, which resulted in an average increase of about 3.0% across the broadband range of 400–800 nm. The optimized films widen the spectrum of light absorbed by conventional PSC cells and reduce reflections across a broad range, enhancing the photovoltaic performance of PSCs. As a result, the PCE of the PSC increased from 14.51% for the reference device without a thin film to 15.67% for the PSC device with an optimized thin film. This study presents a comprehensive solution to the problem of Fresnel reflection and spectral response mismatch of the PSCs, which provides new ideas for the light management of PSCs. Full article

The use of photovoltaics (PVs) and/or photo-thermal (PTs) as primary solar-energy solutions is limited by the low solar conversion of PVs due to the spectral mismatch between the incident radiation and/or the PV material. The PTs are curtailed by the limited absorbance and the low thermal conductivity of the working fluid. A possible solution is the use of luminophores able to perform luminescent down-shifting (LDS) conversion and to incorporate them in liquid or solid layers, which act as spectral beam splitters (SBSs). Dispersed in solid polymer layers, luminophores lead to luminescent solar concentrators (LSC). When dispersed in liquid and placed in front of PVs, luminophores act as working fluids and as SBS, leading to hybrid photovoltaic–photo-thermal (PVT) systems. Here, the SBS filters for PV and PVT systems are reviewed. The contribution of luminophores to electrical and thermal energy production is discussed from theoretical, experimental, and economical perspectives. Recent SBS architectural concepts which combine different optical elements are also considered. These architectures can harness the advantageous properties of LSCs, spectral modulators, and hybridisation in a single structure. By combining these different light-management strategies inside of a single structure, an improvement in the electrical and/or thermal energy production can be achieved. Full article

Different concentrations (1, 3 and 5 wt%) of dysprosium (Dy³⁺)-doped ZnO/SnS (ZSD) nanophotocatalysts using the one-step facile hydrothermal method at 230 ℃ are presented. Their structure, morphological appearance, inclusion of constituent elements, bandgap engineering and luminescent nature are confirmed by the XRD, TEM, XPS, UV-DRS and PL techniques. The photocatalytic activity (PCA) of the prepared nano photocatalysts is studied in the presence of a model pollutant MB under solar light illumination. The degradation kinetics and charge separation mechanism of the ZSD photocatalysts are also presented. Our XRD analysis showed the mixed-phase occurrence of ZnO (hexagonal) and SnS (orthorhombic) from their JCPDS numbers with no additional traces of a doping element, which in turn indicates the purity, substantial crystal structure and high dispersion of the samples. TEM micrographs revealed the appearance of a flake structure and more agglomeration when increasing the dopant concentration. The XPS spectra confirmed the Zn²⁺, Sn²⁺, S²⁻, O²⁻ and Dy³⁺ oxidation states of the constituent elements along with carbon and nitrogen peaks. The Tauc plots showed a decreasing trend in the optical bandgap, i.e., a redshift due to the loading of Dy³⁺ ions into Sn²⁺ ions. The lower recombination rate of photoinduced e⁻-h⁺ pairs is noted when increasing the Dy³⁺ ion content; i.e., the luminescent intensity is suppressed when increasing the concentration of Dy³⁺ ions. The obtained degradation efficiency of the MB dye using the ZSD3 nano photocatalyst is around 98% for a duration of 120 min under solar light irradiation. The prepared ZSD photocatalyst follows pseudo first-order kinetics, and the evidence for attaining a robust Z-scheme PCA is presented in the form of the charge separation mechanism. Full article

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their advantages, such as low toxicity, sustainability, and low cost. Despite the advantages of carbon quantum dots, they remain a low-efficiency material, and it is difficult to fabricate LSCs with a good performance. To address this problem, some of the research has used SiO₂ nanoparticles (Nps) to produce a light-scattering effect that helps to improve the system performance. However, these studies are limited and have not been discussed in detail. In this regard, this research work was designed to evaluate the contribution of the scattering effect in different systems of carbon quantum dots used in a possible luminescent solar concentrator. To carry out this study, C-QDs and SiO₂ Nps were synthesized by hydrothermal methods and the Stober method, respectively. We used different concentrations of both materials to fabricate film LSCs (10 × 10 cm²). The results show that the light scattered by the SiO₂ Nps has a double contribution, in terms of light redirected towards the edges of the window and as a secondary source of excitation for the C-QDs; thus, an improvement in the performance of the LSC is achieved. The best improvement in photoluminescence is achieved when the films are composed of 20% wt carbon quantum dots and 10% wt SiO₂ Nps, reaching a gain of 16% of the intensity of the light incident on the edges of the window with respect to the LSCs where only C-QDs were used. Full article

Combining photovoltaic (PV) and photo-thermal (PT) energy collection strategies in a single system can enhance solar energy conversion efficiencies, leading to increased economic returns and wider adoption of renewable energy sources. This study focuses on incorporating a commercial luminescent organic dye (BASF Lumogen F Red 305) into ethylene glycol to explore its potential for PVT applications. The optical and electrical characteristics of the working fluid were evaluated at different temperatures under direct solar irradiance. Pristine ethylene glycol reduced the maximum PV cell temperature by 10 °C. The inclusion of luminescent dye at various concentrations further reduced the maximum temperature, with the lowest concentration achieving a 7 °C decrease compared to pristine ethylene glycol. The highest dye concentration (0.50 wt%) resulted in a significant temperature reduction of 12 °C. While electrical conversion efficiencies decreased with increasing dye concentration, all concentrations exhibited higher fill factors compared to the bare PV cell during the 100-min illumination period. A ray-tracing model was employed to analyze the behavior of the luminescent dye and quantify transmitted energy for electricity and thermal energy production. Different concentrations showed varying energy outputs, with lower concentrations favoring electrical energy and higher concentrations favoring thermal energy. Economic assessment revealed the viability of certain concentrations for specific countries, highlighting the trade-off between thermal and electrical energy generation. These findings provide valuable insights for PVT system applications in different geographical and economic contexts. Full article

Nowadays, fluorophores with a tetraphenylethylene (TPE) core are considered interesting due to the aggregation-induced emission (AIE) behavior that enables their effective use in polymer films. We propose a novel TPE fluorophore (TPE-BPAN) bearing two dimethylamino push and a 4-biphenylacetonitrile pull moieties with the typical AIE characteristics in solution and in the solid state, as rationalized by DFT calculations. Five different host polymer matrices with different polarity have been selected: two homopolymers of poly(methylmethacrylate) (PMMA) and poly(cyclohexyl methacrylate) (PCHMA) and three copolymers at different compositions (P(MMA-co-CHMA) 75:25, 50:50, and 25:75 mol%). The less polar comonomer of CHMA appeared to enhance TPE-BPAN emission with the highest quantum yield (QY) of about 40% measured in P(MMA-co-CHMA) 75:25. Further reduction in polymer polarity lowered QY and decreased the film stability and adhesion to the glass surface. LSC performances were not significantly affected by the matrix’s polarity and resulted in around one-third of the state-of-the-art due to the reduced QY of TPE-BPAN. The theoretical investigation based on density functional theory (DFT) calculations clarified the origin of the observed AIE and the role played by the environment in modulating the photophysical behavior. Full article

Currently, there are strong and sustained growth trends observed in multi-disciplinary industrial technologies such as building-integrated photovoltaics and agrivoltaics, where renewable energy production is featured in building envelopes of varying degrees of transparency. Novel glass products can provide a combination of thermal energy savings and solar energy harvesting, enabled by either patterned-semiconductor thin-film energy converters on glass substrates, or by using luminescent concentrator-type approaches to achieve high transparency. Significant progress has been demonstrated recently in building integrated solar windows featuring visible light transmission of up to 70%, with electric power outputs of up to P_max ~ 30–33 W_p/m². Several slightly different designs were tested during 2021–2023 in a greenhouse installation at Murdoch University in Perth, Western Australia; their long-term energy harvesting performance differences were found to be on the scale of ~10% in wall-mounted locations. Solar greenhouse generated electricity at rates of up to 19 kWh/day, offsetting nearly 40% of energy costs. The objective of this paper is to report on the field performance of these PV windows in the context of agrivoltaics and to provide some detail of the performance differences measured in several solar window designs related to their glazing structure materials. Methods for the identification and quantification of long-term field performance differences and energy generation trends in solar windows of marginally different design types are reported. The paper also aims to outline the practical application potential of these transparent construction materials in built environments, focusing on the measured renewable energy figures and seasonal trends observed during the long-term study. Full article