Luminescent Solar Concentrators Research Articles

Highly efficient and stable tandem luminescent solar concentrators based on carbon dots and CuInSe2-xSx/ZnS quantum dots.

Semi-transparent large-area luminescent solar concentrators (LSCs) have been considered an essential part of zero-energy or low-energy consuming buildings in the future. Inorganic colloidal quantum dots (QDs) are promising candidates for LSCs due to the advantages of a tunable bandgap, engineered large Stokes shift, and relatively high photoluminescence (PL) quantum yield. However, LSCs that are fabricated using colloidal quantum dots exhibited an inferior stability under long-term illumination, demanding great efforts to explore the highly stable LSCs. Herein, we fabricated large-area (∼100 cm2) tandem LSCs based on highly stable carbon dots (CDs) and highly luminescent near-infrared emitting CuInSe2-xSx/ZnS (CuInSeS/ZnS) QDs. Coupled with a Si diode as a reference, the power conversion efficiency of the corresponding tandem (dimensions: 10 × 10 × 0.5 cm3) and single LSCs (dimensions: 10 × 10 × 0.3 cm3) based on CuInSeS/ZnS QDs under one sun illumination are 0.46% and 0.5%, respectively. For single CuInSeS/ZnS QD based LSCs at a low concentration (0.039 wt%), external and internal quantum efficiencies reach up to 2.87% and 36.37%, respectively. After UV illumination for 8 h, bottom LSCs based on CuInSeS/ZnS QDs retain 93.22% of the initial PL emission, which is higher than that of LSCs (∼80%) without the CD protection. The highly efficient and stable tandem LSCs employing green CDs and NIR CuInSeS/ZnS QDs as PL emitters pave the way for the realization of large area building-integrated photovoltaic (BIPV) devices.

Assessing the performance of sustainable luminescent solar concentrators based on chemically recycled poly(methyl methacrylate)

The performances of PMMA luminescent solar concentrators fabricated from virgin and recycled monomers were compared to highlight their similar efficiencies and account for the effect of the purity of the latter on the longevity of the device.

Fluorescent Polymer Nanoparticles Containing Perylene Diimides for Application in Luminescent Solar Concentrators

Reabsorption of the luminescence at high concentration is one of the major challenges in organic luminescent solar concentrators (LSCs). One potential and promising solution involves enhancing the Stokes shift of...

Synergistic engineering of the Stokes shift for highly efficient and stable quasi-2D perovskite luminescent solar concentrators

Three new quasi-2D perovskite/PVDF composite films with a high PLQY and large Stokes shift are obtained, PEA2MAx−1PbxBr3x+1/PVDF (x = 2, 3, 4) (PMx−1PF). Among them, the LSC based on PM2PF exhibits a remarkable ηext of up to 4.9%.

Eco-friendly and high-efficiency luminescent solar concentrators enabled by green-emissive manganese halide hybrids

The PLQY of (BTMA)2MnBr4 is nearing 100%. This enables the obtained film to display bright green light emission and exceptional transparency. Besides, the (BTMA)2MnBr4@PEO-based LSC realizes a PCE of 2.06% and an ηint of 45.33%.

Highly efficient luminescent solar concentrators based on selective laser-induced crystallization in CsPbBrxCl3−x (x = 0–3) doped glass

The optical conversion layer with CsPbBrxCl3 − x (x = 0 − 3) NCs linear array was prepared in the precursor glass by femtosecond laser direct writing.

Fabricating a scattering–fluorescent luminescent solar concentrator synchronously to achieve broad-spectrum solar energy utilization and light pollution inhibition

A scattering–fluorescent luminescent solar concentrator is fabricated with the synergistic function of reducing the light pollution and improving the photoelectric conversion.

Design of J-aggregates-like oligomers built from squaraine dyes exhibiting transparency in the visible regime and high fluorescence quantum yield in the NIR region.

New materials for transparent luminescent solar concentrators (TLSCs) are of large interest. Therefore, we investigated the optical properties of J-aggregates-like oligomers (hereinafter referred to as J-aggregates) based on covalently bound squaraine dyes in toluene solvent using DFT and TD-DFT methods. In addition, the rate constants needed for the prediction of fluorescence quantum yield (QY) have been calculated using Fermi's Golden rule and vertical harmonic approximation (VH) for ground and excited states. In the context of QY prediction, different broadening of the lineshape has also been employed. We found that J-aggregates based on squaraine dyes exhibit near-infrared (NIR) selective absorption and emission as well as high fluorescence QY. Comparison of the properties obtained for dimers, trimers and tetramers belonging to two classes (SQA and SQB) of J-aggregates allows us to select the tetramer of SQA J-aggregates as suitable for application. The scaling model for N ≥ 4 monomer subunits supports quantitative findings. Therefore, we propose J-aggregates containing N ≥ 4 subunits of SQA with a central squaric acid ring with two oxygen atoms in toluene solvent as a suitable candidate for TLSC application.

Simulation of the Effects of Geometry on Performance of Luminescent Solar Concentrator Photovoltaic Devices

Simulation of the Effects of Geometry on Performance of Luminescent Solar Concentrator Photovoltaic Devices

A highly transparent and efficient luminescent solar concentrator based on nanosized molybdenum clusters and quantum-cutting perovskite nanocrystals

Introducing a dual-luminophore LSC with rhenium nanoclusters and quantum-cutting perovskite for high-efficiency, transparent photovoltaic windows.

Exploring the optical management and efficiency limit of luminescent solar concentrators based on advanced luminophores

This work provides new insights for predicting the efficiency limit of LSCs. The use of tandem LSCs based on luminophores of singlet-fission and CuInSe2/ZnS is considered a promising method to achieve optimal efficiency.

Highly efficient and high color rendering index multilayer luminescent solar concentrators based on colloidal carbon quantum dots

Compared to the silicon-based photovoltaics, large-area luminescent solar concentrators (LSCs) can be used as smart PV window for building-integrated photovoltaics (BIPVs). However, because of the low quantum yield of the fluorophores, and reabsorption energy loss, the current obtained large-area LSCs have low optical efficiency. Herein, we demonstrated highly efficient and semitransparent multilayer LSCs based on three types of carbon quantum dots (C-dots). The blue and green C-dots were synthesized using vacuum heating approach and the orange C-dots were synthesized using solvothermal approach. The as-prepared B-, G- and O-C-dots have the QYs of 90 %, 73 % and 72 %, respectively, with large Stokes shift (0.37–0.73 eV). By optimizing the concentration of the C-dots in each layer, the best LSC (100 cm2) with multilayer structure exhibited an external optical efficiency of 9.1 %, and a power conversion efficiency (PCE) of 6.0 %, which are higher than that of most of reported LSCs. The simulations indicate that optimized multilayer LSCs could have a theoretical external optical efficiency over 12 % for 1 m2 devices. Besides high optical efficiency, the multilayer LSCs also have high Color Rendering Index (above 80) and high average visible transmission (above 70 %), which make the as-prepared LSCs suitable for potential commercial BIPVs.

Artificial neural networks for predicting optical conversion efficiency in luminescent solar concentrators

Developing light-harvesting materials able to shape the sunlight to cope with the absorption region of photovoltaic (PV) cells presents an opportunity for the utilization of spectral converters like the luminescent solar concentrators (LSCs). This study explores the use of artificial neural networks (ANNs) to predict the optical conversion efficiency of spectral converters, based on the material properties employed in their production, without the need for expensive and time-consuming experimental testing. To predict efficiency as a function of materials and manufacturing processes, ANNs were trained using data from previously documented physical implementations. The findings indicate that ANNs, having 97 and 19 neurons in the hidden layers, provide accurate efficiency predictions, making them a valuable tool for designing and optimizing spectral converting systems. The proposed model was validated and got a mean square error in the order of 10−5 for the optical conversion efficiency. The trained ANN introduced a novel methodology for predicting the optical efficiency of spectral converters, opening the door to the application of machine learning as a decision-making tool for material design, and eliminating the necessity for physical device implementations.

Photophysical Analysis of Aggregation-Induced Emission (AIE) Luminogens Based on Triphenylamine and Thiophene: Insights into Emission Behavior in Solution and PMMA Films.

Aggregation-Induced Emission (AIE) luminogens have garnered significant interest due to their distinctive applications in different applications. Among the diverse molecular architectures, those based on triphenylamine and thiophene hold prominence. However, a comprehensive understanding of the deactivation mechanism both in solution and films remains lacking. In this study, we synthesized and characterized spectroscopically two AIE luminogens: 5-(4-(bis(4-methoxyphenyl)amino)phenyl)thiophene-2-carbaldehyde (TTY) and 5'-(4-(bis(4-methoxyphenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (TTO). Photophysical and theoretical analyses were conducted in both solution and PMMA films to understand the deactivation mechanism of TTY and TTO. In diluted solutions, the emission behavior of TTY and TTO is influenced by the solvent, and the deactivation of the excited state can occur via locally excited (LE) or twisted intramolecular charge transfer (TICT) state. In PMMA films, rotational and translational movements are constrained, necessitating emission solely from the LE state. Nevertheless, in the PMMA film, excimers-like structures form, resulting in the emergence of a longer wavelength band and a reduction in emission intensity. The zenith of emission intensity occurs when molecules are dispersed at higher concentrations within PMMA, effectively diminishing the likelihood of excimer-like formations. Luminescent Solar Concentrators (LSC) were fabricated to validate these findings, and the optical efficiency was studied at varying concentrations of luminogen and PMMA.

From Ancient Blue Pigment to Unconventional NIR Phosphor: A Thermal-Stable Near-Infrared I/II Broadband Emission from Ca1-xSrxCuSi4O10 Solid Solution.

Phosphors used in NIR spectroscopy require broadband emission, high external quantum yield, good ability, as well as a tunable spectral range to meet the detection criteria. Two-dimensional copper silicates MCuSi4O10 (M = Ca, Sr, Ba) play an important part in ancient art and technology as synthetic blue pigments. In the recent years, these compounds were reported to show a broad near-infrared emission when excited in the visible region. Inspired by the tunable structure of MCuSi4O10, a series of broadband phosphors Ca1-xSrxCuSi4O10 were designed for realizing continuously tunable NIR emission by a modulated Cu2+ crystal field environment. The emission maximum exhibits a red shift from 915 to 950 nm and the integral intensity enhances as the Sr2+ content varies in the range of 0-0.50, which is led by the lattice expansion and the following weakened crystal field splitting on tetrahedral-coordinated Cu2+. Compared to CaCuSi4O10, the optimized sample Ca0.5Sr0.5CuSi4O10 shows enhanced NIR emission by about 2.0-fold. It exhibits quite a high external quantum efficiency covering the NIR-I and -II regions (λmax = 950 nm, fwhm = 135 nm, EQE = 26.3%) with a strong absorption efficiency (74.7%) and a long excited-state lifetime (134 μs). These solid-solution phosphors (x = 0.0-0.5) show excellent thermal stability and maintain over 50% of the RT intensity at 200 °C. The optimized phosphor was encapsulated with red-light chips to fabricate NIR pc-LED and put into night-vision application. These good properties make these Cu2+-activated NIR phosphors appealing for multiple applications such as nondestructive testing, night version, lasers, and luminescent solar concentrators.

Constructing highly efficient and ultra-stable (against Temperature, Humidity and Sunlight) luminescent solar concentrators by using dendritic CsPbBr3@SiO2 particles

Conventional perovskite quantum dots (PQDs) suffer long-term stability, further limiting practical application of luminescent solar concentrators (LSCs). In this work, novel dendritic CsPbBr3@SiO2 particles with bright solid-state green light emission and 46 % of photoluminescence quantum yield (PLQY) have first been synthesized via one-step solid-phase calcination method. The dendritic CsPbBr3@SiO2 particles have then been used as fluorescent material for construction of LSCs along with using organosilicon polymers with better compatibility as waveguide materials. Single-layer thin film LSCs and overall curing LSCs are easily prepared by the casting and curing method, exhibiting high external optical efficiency (ηopt) of 7.88 % and 10.92 %, respectively. The maximum internal quantum efficiency (ηint) of thin film LSCs and overall curing LSCs reach 45.09 % and 44.07 %, respectively, while their maximum external quantum efficiency (ηext) of 29.42 % and 34.07 % are obtained, respectively. Importantly, both types of LSCs show excellent stability, maintaining above 92 % of the initial ηopt under high-relative-humidity (RH = 90 %), high-temperature (60 °C) and sunlight exposure conditions for two weeks or room temperature environment for twenty weeks. Moreover, both types of LSCs at optimal conditions have good transparency (>40 % over 515 nm of light wavelength). Otherwise, both types of LSCs have higher ηopt than that of the previous related work.

Dendrimer-Encapsulated Halide Perovskite Nanocrystals for Self-Powered White Light-Emitting Glass.

Perovskite nanocrystals (PNCs) have attracted substantial attention due to their inspiring intrinsic merits such as low cost, high performance, and solution processability, but when it comes to the usage of blends of different colored PNCs with the purpose of covering the broadband spectrum field, the high degree of instability remains a major bottleneck. Herein, we report a family of dendritic ammonium ligands that act as stiff shell-encapsulating PNCs for improving their stability and suppressing ion permeability in mixed colloidal PNC solutions. The as-synthesized ligand-encapsulated PNCs notably achieve near-unity photoluminescence quantum yields (PLQYs) and strongly resist the unwanted ion exchange reaction under aggressive anion source attack. To fabricate self-powered white-emitting glass, the stabilized mixed colored PNCs were embedded into the laminated glass, which simultaneously acted as absorbers-emitters for luminescent solar concentrators (LSCs) and emitters for white light-emitting glass.

Fabrication and comprehensive investigations on NBD-based luminescent solar concentrator

The design and development of innovative chromophoric materials for luminescent solar concentrators (LSCs) is an emerging area of research in the pursuit of low-cost photovoltaic technology. In this study, we devised and developed the optically active fluorescent dye NBDNH2 based on the skeleton of a benzoxadiazole. In NBDNH2, the electron donating amino group and the electron-withdrawing nitro group are the responsible for intramolecular charge transfer transition as well as fluorescence upon photoexcitation. The structural and photophysical properties of NBDNH2 dye have been meticulously investigated. In addition, the solvent-property relationships also investigated through time-resolved fluorescence and 1H NMR measurements. The photophysical studies reveal that the dye has a moderate Stokes shift, a long fluorescence lifetime and provides guidance for the development of LSCs. NBDNH2 was doped in polymethyl methacrylate (PMMA) to fabricate LSC devices. Due to promising optical properties, the NBDNH2 based LSC (5 × 5 × 0.3 cm3) showed the internal and external photon efficiencies as high as 29.4 % and 3.84 %, respectively. When connected with the photovoltaic cell, the champion device yielded power conversion efficiency of 1.32 % and 0.64 % with scattering and black background, respectively. Based on the findings, we unequivocally envisaged that the benzoxadiazole-based ICT probe is a prospective optical material for LSC applications.

Increased NIR photoluminescence of Egyptian blue via matrix effect optimization

The exceptionally high NIR photoluminescence of the ancient pigment Egyptian blue is due to its very stable phase cuprorivaite (CaCuSi4O10). This compound has recently attracted significant attention, leading to numerous applications for sensors, luminescent solar concentrators, energy-saving, and biomedicine. Here we report an innovative manufacturing process for producing high-grade cuprorivaite, characterized by fine crystal grains and a significantly increased NIR photoluminescence emission. The unprecedented ultra-high NIR emission (quantum yield ΦEM ≈ 30 %) is almost three times higher than the best one reported so far. This is an important turning point for the extension of applications of cuprorivaite to new sectors and can greatly boost its exploitation. The new high-efficiency cuprorivaite is obtained by solid-state synthesis, using silica nanoparticles as a starting material and avoiding fluxing agents. No doping with rare-earths or other elements has been employed, making synthesis straightforward and sustainable. The material obtained has been fully characterized in terms of crystalline, morphological, and optical properties and compared to cuprorivaite obtained through traditional melt-flux synthesis. The main difference observed is that the tiny crystals obtained through the new synthesis method are practically devoid of the glassy phase, rich in copper and impurities, that is instead largely present in Egyptian Blue pigment synthesized with traditional melt-flux synthesis. We speculate that this glassy phase is responsible for the partial suppression of the intrinsic photoluminescence of cuprorivaite, demonstrating how limiting the glassy phase can increase the external quantum efficiency of Egyptian blue.

Theoretical investigation of asymmetric light interfaces for increasing optical efficiency of luminescent solar concentrators via integration of finite element simulation results with Monte Carlo ray tracing

Theoretical investigation of asymmetric light interfaces for increasing optical efficiency of luminescent solar concentrators via integration of finite element simulation results with Monte Carlo ray tracing