Luminescent Solar Concentrators Research Articles

Monte Carlo Modeling of a High‐Efficiency Tandem Luminescent Solar Concentrator Containing a Polarization Volume Grating Layer

This article develops a Monte Carlo model to optimize a newly introduced tandem luminescent solar concentrator. This innovative structure comprises two parallel transparent polymeric waveguides separated by an air gap. The first waveguide, which is exposed to sunlight, contains fluorophores and performs as a traditional luminescent solar concentrator. In contrast, the second waveguide is equipped with an inner polarization volume grating layer, strategically placed to couple the emitted photons within the escape cone, directing them into the second waveguide and preventing reabsorption. The finite difference time domain method is employed to optimize the performance of this grating. The results show a significant improvement in external photon efficiency compared to the conventional luminescent solar concentrator.

New Luminescent Solar Concentrator Windows Using PMMA-InP/ZnS Nanohybrid Coating Films for Green Building Applications

Green fluorescing PMMA-InP/ZnS nanohybrid coating films were applied onto FTO glass substrates through the traditional spin coating technique for the development of luminescent solar concentrator windows. Examination using transmission electron microscopy (TEM) displayed good morphology and uniform dispersion of InP/ZnS quantum dots (QDs) in PMMA matrix, whereas X-ray diffraction (XRD) indicated the amorphous nature and good adhesion to FTO glass substrate. Investigations of the influence of varying QD concentrations on spectral photophysical characteristics were conducted using techniques such as optical absorption, transmission, fluorescence spectroscopy, and the chromaticity diagram (CIE 1931). The films exhibited good transparency in the visible spectrum, approximately 87%, with reduced transparency in the near-infrared (NIR) region, approximately 26%. The films have various shades of green colors closely aligned with the sensitivity of the human eye, as demonstrated by CIE 1931 chromaticity diagram. Skin depth calculations spanning the UV to NIR wavelengths (200-2400 nm) showed a marked decrease in electromagnetic wave penetration correlating with increased InP-ZnS QD concentrations. Fluorescence spectroscopy revealed the highest fluorescence intensity and quantum yield of 71% for QDs concentration of 0.15wt% coupled with outstanding photostability properties after exposure to UVA radiation (365 nm) for 72 h. This optimization effectively reduces the infiltration of detrimental solar radiation into buildings, encompassing ultraviolet and infrared wavelengths. The research outcomes are consistent with the objectives of Sustainable Development Goals SDG7 and SDG 11, in sun-drenched regions such as Saudi Arabia, as PMMA-InP/ZnS nanohybrid coating films can be tailored to meet the spectral needs of energy-efficient windows.

Research on Luminescent Solar Concentrators (LSCs)

Research on Luminescent Solar Concentrators (LSCs) is crucial for enhancing the energy density of sunlight and lowering the costs associated with silicon solar cells. This paper thoroughly evaluates and compares the performance of three different LSC materials: Rhodamine B (RBB), Rhodamine 6G (R6G), and Coumarin 6 (C6). The study focuses on several key metrics, including Stokes shift, external quantum efficiency, concentration factor, and conversion factor. By analyzing these parameters, the paper aims to elucidate how each material's properties influence overall performance, providing valuable insights into optimizing LSC design for improved energy harvesting. In order to pave the way for more widespread adoption of LSCs in solar applications, enhancing their role in sustainable energy systems.

Core‐Shell Colloidal Quantum Dots for Energy Conversion

AbstractColloidal quantum dots (QDs) are promising building blocks in optoelectronic devices, mainly due to their size/shape/composition‐tunable properties. Core–shell QDs, in particular, offer enhanced stability, mitigated photoluminescence blinking, and suppressed non‐radiative recombination compared to plain QDs, making them highly promising for energy conversion applications such as photovoltaic devices, luminescent solar concentrators, solar‐driven hydrogen production, and light‐emitting diodes. Here, a comprehensive analysis of core–shell QDs in energy conversion technologies is provided. Emerging design strategies are explored and various synthetic methods focusing on optimizing band structure, band alignment, and optical properties are critically explored. Insights into the structure‐property relationship are discussed, highlighting recent advancements and the most effective strategies to enhance energy conversion performance. The review is concluded by addressing key challenges and proposing future research directions, emphasizing the need for rational design, precise synthesis, effective surface engineering, and the integration of machine learning to achieve optimized properties for technological applications.

Double-Shell Encapsulation of Lead-Free Tin Halide Perovskite for Self-Powered Smart Windows.

Luminescent solar concentrators (LSC) have the potential application in building integrated photovoltaic (BIPV). 0D tin-based perovskites are a promising embedding phosphor in LSC due to the large Stokes shift and high photoluminescence quantum yield. But the instability and uncontrollable crystal growth are severe limiting their successful utilization in device fabrication. To tackle these issues, double-shell encapsulated configurations are presented, soft ligands of hypophosphorous acid and hard-shell of hollow mesoporous silica are simultaneously suppressing the oxidation of Sn2+ and restricting crystal growth within nano-matrix. The stable phosphor is subsequently embedded into LSC for harvesting solar energy and the resulting output power efficiently drives the combined electrochromic glass under natural light. These fabricated devices also offer the self-adaptable switch on/off functionality to regulate light absorption with variable solar irradiation intensity in real time. This approach is anticipated to open new avenues for utilizing lead-free perovskite nanomaterials in self-powered smart windows for BIPV.

Optical Applications of CuInSe2 Colloidal Quantum Dots.

The distinctive chemical, physical, electrical, and optical properties of semiconductor quantum dots (QDs) make them a highly fascinating nanomaterial that has been extensively studied. The CuInSe2 (CIS) QDs demonstrates great potential as a nontoxic alternative to CdSe and PbSe QDs for realizing high-performance solution-processed semiconductor devices. The CIS QDs show strong light absorption and bright emission across the visible and infrared spectrum and have been designed to exhibit optical gain. The special characteristics of these properties are of great significance in the fields of solar energy conversion, display, and electronic devices. Here, we present a comprehensive overview of the potential applications of colloidal CIS QDs in various fields, with a particular focus on solar energy conversion (such as QD solar cells, QD-sensitized solar cells, and QD luminescence solar concentrators), solar-to-hydrogen production (such as photocatalytic and photoelectrochemical H2 production), and QD electronics (such as QD transistors, QD light-emitting diodes, and QD photodetectors). Furthermore, we offer our insights into the current challenges and future opportunities associated with CIS QDs for further research.

Fabrication and performance evaluation of large–scale luminescent and plasmonic luminescent solar concentrator modules

This study presents the detailed fabrication and performance evaluation of large–scale luminescent solar concentrator (LSC) and plasmonic luminescent solar concentrator (PLSC) modules. Individual LSC, PLSC, and reference devices have been fabricated with dimensions of 10 x 10 x 0.5 cm. Five devices of each type were connected in series, ensuring correct photovoltaic cell polarity, to form cohesive modular groups with minimal mismatch. These solar concentrators were subsequently integrated into an outdoor panel designed to accommodate the modules for outdoor performance evaluations. Outputs of 240 mW, 213 mW, and 46 mW were observed for the individual PLSC, LSC and reference devices respectively from an indoor solar simulator test outputting 900 W/m2. Outdoor performance analysis has highlighted that the inclusion of metal nanoparticles within the PLSCs enhanced the outputs by 65% on average with a maximum enhancement of 88.6% observed over the course of a single day. The series connection within the LSC modules demonstrated enhanced scalability and potential for practical application in solar energy systems. This innovative module configuration provides valuable insights into the advancement of luminescent solar concentrators through plasmonic enhancement, contributing to the broader goal of optimising solar energy harvesting.

Time, temperature and concentration resolved Yb3+ luminescence study in co-sputtered Cu2-xGaxS2 (0.1 < x < 1.6) thin films with a Cu–Ga composition gradient

The broad class of Cu(Al,Ga,In) (S,Se,Te)2 solar absorber materials when doped with Yb3+ are interesting for thin film based luminescent solar concentrator (LSC's) application. In this work the strong and broad absorption properties of co-sputtered CuGaS2 (CGS) thin films combined with the luminescent properties of Yb are reported. Energy-dispersive x-ray spectroscopy (EDS), x-ray diffraction, transmission, excitation, and temperature dependent emission as well as radiative lifetime measurements are performed on thin films with varying Cu:Ga ratios and Yb3+ concentrations. It is found that Yb3+ emission can be broadly sensitized by the host in the range of 200–600 nm. A lower Cu:Ga ratio, crystallinity and post annealing in air provides a positive impact on the sensitization of Yb3+ emission. The temperature dependent time integrated decay curves show a clear thermal energy barrier of about 0.2 eV. Because the exponential tail, with a lifetime of 110 μs, is constant with temperature, we conclude that the barrier is connected to the thermal release of electrons trapped at the Yb2+ ground state. The low energy transfer efficiency from the host to the Yb dopant is attributed to efficient non-radiative electron-hole pair recombination. The prospects and design criteria of Cu(Al,Ga,In) (S,Se,Te)2 solar absorber materials for LSC applications is the further subject of the discussion.

Luminescent solar concentrator containing Parylene-C microfibrous thin film infiltrated with Lumogen F Red 305

Abstract Luminescent solar concentrators (LSCs) were made by the infiltration of microfibrous thin films (µFTFs) of Parylene C by Lumogen F Red 305 (LFR305), in order to maximize the concentration of light made available to a photovoltaic solar cell (PVSC). The Parylene-C µFTFs with either tilted columnar or chevronic morphology were fabricated using physicochemical vapor deposition and infiltrated with LFR305 using thermal evaporation. Application of a voltage across a photoresistor illuminated by a solar simulator (AM1.5) through an LFR305-infiltrated Parylene-C LSC resulted in an enhancement of the ON-OFF minimum current ratio by a factor of 1.5 ± 0.29 compared to the ratio before LFR305 infiltration/deposition, regardless of morphology; furthermore, LFR305 infiltration enhanced the ON-OFF minimum current ratio by 56.5 ± 21.5 %, depending on the morphology. The LSC concentration factor was determined to be 8.7 ± 3.4 after integration with a monocrystalline-silicon solar cell, depending on the morphology.

Durable Quantum Dot‐Based Luminescent Solar Concentrators Enabled by a Photoactive Block Copolymer

AbstractQuantum dot (QD)‐based luminescent solar concentrators (LSCs) promise to revolutionize solar energy technology by replacing building materials with energy‐harvesting devices. However, QDs degrade under air, limiting the long‐term performance of QD‐LSCs. This study introduces an innovative approach to prevent QDs degradation by utilizing a photoactive polymer matrix (maleic anhydride‐grafted poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene, SEBS‐g‐MA). This strategy has been tested outdoors over a 2‐year period on five LSCs, followed by characterization of the weathered devices. The tested LSCs consist of three QD‐LSCs (CuInS2/ZnS, InP/ZnSe/ZnS, CdSe/CdS/ZnS core/shell QDs), alongside a Lumogen dye‐based LSC and a luminophore‐free LSC. The study yields several findings: 1) SEBS‐g‐MA undergoes photochemistry outdoors, 2) SEBS‐g‐MA accelerates the photodegradation of Lumogen, 3) the power conversion efficiency of CdSe‐based QD‐LSC drops by 80% due to reduction of the photoluminescence quantum yield, and 4) under illumination SEBS‐g‐MA protects CuInS2 and InP‐based QDs from degradation, ensuring a stable performance during the entire study. This work thus demonstrates for the first time that the interaction between the luminophores and the matrix is a critical determinant of the long‐term success of LSCs. Leveraging on the fact that this is the longest outdoor study to date, we propose design rules for highly efficient and stable QD‐LSCs.

InP QDs modified GaAs/PEDOT:PSS hybrid solar cell with efficiency over 15.

GaAs heterojunction solar cells are known as promising substitutions for traditional GaAs solar cells for their low cost and performance potential. Nevertheless, the further performance enhancement is hindered by insufficient spectral absorption and nonradioactive recombination. In this work, an InP quantum dot (QD) modified GaAs/PEDOT:PSS solar cell is designed to enhance spectrum utilization and suppress the nonradioactive carriers loss and the solar cell efficiency at 15.08% is achieved. Furthermore, InP QDs used in this work are synthesized by a novel hydrothermal method. During the synthesis process, β-cyclodextrin (β-cyc) was introduced into the reactants and acted as a reaction cell, isolating water and oxygen, enabling the reaction to proceed in ambient air. InP QDs synthesized by this method can achieve band engineering by altering reactant ratios, thereby effectively serving as both a Luminescent Solar Concentrator (LSC) and a Front Surface Field (FSF) in GaAs/PEDOT:PSS solar cells. This work demonstrates an inspiring way to synthesize InP QDs and optimize the performance of GaAs hybrid solar cells.

9H-carbazole and indolo[3,2-b]indole-based fluorophores for potential application in luminescent solar concentrators

In the present study, four new organic fluorophores, consisting of a central 9H-carbazole (CBZ) or indolo[3,2-b]indole (IDID) moiety, functionalized with (S)-3,7-dimethyl-1-octyl branched chains and connected to lateral 2-thienylethynyl or 2-thiophenylpropynone units, were synthesized by means of Pd-catalyzed cross-coupling reactions and investigated for potential application in luminescent solar concentrator (LSC) systems. The photophysical properties of four final dyes were first evaluated in solution of four solvents with different polarity (toluene, chloroform, acetone, acetonitrile). For the IDID-based compound 4, which proved to be the best candidate, the photophysical properties in thin films with PMMA matrix at different concentrations (0.4–2.0 wt%) were also investigated. Finally, their efficiency parameters as LSC systems connected to a photovoltaic (PV) cell were evaluated, obtaining a maximum device efficiency (ηdev) of 0.46 ± 0.02 % at 1.2 wt%: these are very promising PV performances for a N-heteroarene-based dye, coupled with a sufficient stability in accelerated aging tests.

Aggregation-Induced Enhanced Red Emission Graphene Quantum Dots for Integrated Fabrication of Luminescent Solar Concentrators.

Graphene quantum dots (GQDs) commonly suffer from the fluorescence problem of aggregation-caused quenching under high-concentration loading or in the solid state, which seriously hinders the application. Here we report a type of GQDs with red aggregation-induced enhanced emission (AIEE). It is confirmed that the aggregation state of the AIEE GQDs is a J-aggregate. The GQDs/poly(methyl methacrylate) film presented a photoluminescence quantum yield as high as 60.81%, and the record-high performance of luminescent solar concentrators (LSCs) was achieved. The power conversion efficiency (ηPCE) is up to 8.35% and the external optical efficiency (ηext) is ∼8.99% for the GQD-based LSCs (45 mW/cm2). Even under one sun illumination (100 mW/cm2), the corresponding ηPCE and ηext values are 3.12% and 4.52%, respectively. The internal photon efficiency (ηint) of an LSC device is about 5.02%. The synthesis of AIEE GQDs bridges the research gap in the emission mechanism of AIEE in GQDs.

Luminescent Solar Concentrators for Greenhouse Applications Based on Highly Luminescent Carbon Quantum Dots

Carbon quantum dots (CQDs) are promising luminophores for luminescent solar concentrators (LSCs) in transparent photovoltaic greenhouse covers due to their high ultraviolet (UV)‐light absorption coefficient, which is vital for plant growth. Herein, high quantum yield (75%) and large Stokes shift (0.706 eV) CQDs are synthesized by a simple, fast, cheap, and mass scalable method. A comprehensive study on the LSC engineering is carried out. Thin layers of CQDs with different concentrations of 1, 3, and 5 wt% and different number of layers (1–5) are coated on glass and poly(methyl methacrylate) (PMMA) waveguides, sized 5 × 5 × 0.6 and 15 × 15 × 0.6 cm3. The best performing single‐layer LCS exhibits power conversion efficiency (PCE) and optical efficiency as high as 1.6% and 6.5%, respectively (LSC size 5 × 5 × 0.6 cm3), and 1.19% and 3.27% (LSC size of 15 × 15 × 0.6 cm3), respectively. Over 90 days, stability tests show a 2% PCE decrease. Tests on a small‐scale greenhouse model demonstrate that transparent photovoltaic LSC roofs not only produce electricity but also control temperature inside the greenhouse. Hence, CQD‐based LSCs synthesized by the scalable method can be used in commercialization of transparent greenhouses photovoltaic covers.

Highly Efficient and Stable Luminescent Solar Concentrator Based on Light‐Harvesting and Energy‐Funneling Nanodot Pools Feeding Aligned, Light‐Redirecting Nanorods

Highly Efficient and Stable Luminescent Solar Concentrator Based on Light‐Harvesting and Energy‐Funneling Nanodot Pools Feeding Aligned, Light‐Redirecting Nanorods

Edge-Light: Exploiting Luminescent Solar Concentrators for Ambient Light Communication

A recent advance in embedded Internet of Things (IoT) exploits ambient light for wireless communication. This new paradigm enables highly efficient links via simple light modulation, but the design space has a fundamental constraint: in most State of the Art (SoA) studies, the link can only follow the propagation direction of ambient light. Consider, for example, a swarm of drones and ground robots that want to communicate with sunlight. Drone-to-robot communication could be possible because sunlight travels downwards from the air (drone) to the ground (robot), allowing drones to modulate light to send information to robots beneath them. Robot-to-robot communication, however, is not possible because sunlight does not travel sideways (parallel to the ground). To allow 'lateral communication' with ambient light, we propose using Luminescent Solar Concentrators (LSC). These optical components receive ambient light on their surface and re-direct part of the spectra towards their edges. Considering this optical property of LSC, our work has three main contributions. First, we benchmark various optical properties of LSC to assess their performance for ambient light communication. Second, we combine LSC with liquid crystal (LC) shutters to form lateral links with ambient light. Third, we test our links indoors and outdoors with artificial and natural ambient light, by enhancing two robots with our LSC transceivers and showing that they can exchange basic commands and coordinate tasks by communicating only with sunlight.

Glycerol as Reaction Medium for Sonogashira Couplings: A Green Approach for the Synthesis of New Triarylamine-Based Materials with Potential Application in Optoelectronics.

This study focuses on the design, eco-friendly synthesis, and characterization of several novel three-legged triphenylamine derivatives. By performing Sonogashira couplings of functionalized aryl iodides with tris(4-ethynylphenyl)amine in glycerol, a readily available bio-derived solvent, we achieved the synthesis of target products in short times and high yields, up to 94 %, with consistently lower E-factors and reduced costs compared to standard conditions using toluene as the reaction medium. The target molecules possess a D-(π-A)₃ or D-(π-D)₃ structure, where an electron-donating core connects to three electron-donating (D) or electron-accepting (A) peripheral aromatic subunits through an acetylene spacer. Their main optical and electronic properties have been determined experimentally and by DFT simulations and suggest a possible implementation in energy conversion technologies such as luminescent solar concentrators (LSCs) and perovskite solar cells (PSCs).

Utilizing molecular states of carbon quantum dots (CQDs) to efficiently harvest outdoor and indoor energy via luminescent solar concentrator

Luminescent solar concentrators (LSCs) offer a huge potential for electricity generation due to their ability to harvest direct and diffused light. Among numerous fluorophores for LSCs, carbon quantum dots (C-QDs) are promising candidates due to their non-toxic nature, tunable optical features, and cost-effective synthesis. State-of-the-art LSCs utilizing C-QDs focus on solar energy harvesting, while their potential to harness indoor light for electricity generation is yet to be explored. In this study, we rationally fabricated C-QDs based LSC for efficient energy harvesting under both outdoor and indoor illuminations. Through a facile solvothermal pyrolysis technique, we synthesized the molecular states assisted C-QDs exhibiting a strong absorbance in the visible region that matched well with the outdoor and indoor light spectra. Laminated LSCs were fabricated by coating C-QDs/polyvinyl alcohol (PVA) film (photoluminescence quantum yield 71 %) on two glass substrates and joining them with an interlayer of refractive index matching polymer. Given geometry not only protects C-QDs/PVA film from external damage but also prevents light scattering losses that were prominent in an open C-QDs/PVA layer. External efficiency (ηext) of the small-to-large area LSCs under different illuminations were estimated using an analytical approach. The results showed that under outdoor (air mass 1.5 global spectrum) illumination and without scattering background, a large-area (10 × 10 × 0.6 cm3) LSC at an optimized concentration of C-QDs exhibited ηext of 3.1 %. When connected with the silicon PV cell, the same LSC yielded a power conversion efficiency (ηPCE) of 0.34 %. Among various indoor illuminations (light-emitting diode (LED)-daylight, LED-warm white, and fluorescent-daylight (CFL)), the best performance was shown under LED-daylight with the ηext and ηPCE of 7.4 % and 0.30 %, respectively. This study offers enormous potential for the adoption of C-QDs based LSC not only in building exteriors (such as windows and facades) but also in the places where artificial lights are used.

Self‐Powered Luminescent Solar Concentrators‐Integrated Temperature Detection System with High Thermal Tolerance by Reversible Thermal Photoluminescence Luminophores

AbstractIt is still a challenge to prepare the red‐emissive perovskite‐polymer composite with high photoluminescence quantum yield (PLQY) and reversible thermal photoluminescence (RTPL), which is key for improving the thermal tolerance of luminescent solar concentrators (LSCs). In this work, the red‐emissive (661 nm) CsPb(Br0.25I0.75)3‐PMMA composite with high PLQY of 85.96% and favorable RTPL below 160 °C is reported via a strategy of the defect passivation by halide ligand additives. The composite film possesses excellent long‐term stability in air, water, and high temperature environments. Then, a self‐powered temperature detection system, which consists of LSCs and a temperature detection module based on the RTPL composite film, is fabricated. On one hand, RTPL composite makes LSCs of superior thermal tolerance even after 100 cycles of temperature between room temperature and 160 °C. On the other hand, RTPL composite in the opaque box of the temperature detection module can give rise to the signal light without the interference of ambient light. As a result, the self‐powered temperature detection system achieves the quantitative temperature data display at different environment lights for 24 h in a day.

(Invited) Tuning the Optoelectronic Properties of Inorganic and Carbon-Based Quantum Dots for Highly Efficient Luminescent Solar Concentrators

Luminescent solar concentrators (LSCs) are an old class of devices based on semitransparent windows, in which luminophores are embedded in a transparent matrix.[1] The luminophores can absorb and re-emit solar light and are able to generate electric power by collecting the re-emitted light at the borders of the slab. In the past, lab-to-fab transition of such devices was impeded by intrinsic limitations of the luminophores in terms of low quantum yield, strong resorption due to small Stokes shift, low optical and photoconversion efficiency of the final device. In the last years, a renaissance of such devices has been driven by the development of new 0-dimensional nanostructures, with tunable optical properties, which can guarantee good performance of LSCs.[2,3] Specifically, high quantum yield can be obtained; resorption losses can be limited by modulating the Stokes shift; final color of the window can be tuned by tuning light absorption properties; UV and IR parts of solar spectrum can be exploited without affecting window transparency. We will give examples of different 0-dimensional systems, which have been developed toward high efficiency LSCs, among which inorganic quantum dots and carbon dots.[4,5] Several strategies will be illustrated to tune the optoelectronic properties of the luminophores, including doping, core-shell structuring, and surface treatments.