Luminescent Solar Concentrators Research Articles

Enhanced Efficiency of Silicon Solar Cell by New Salophen Complexes Embedded PMMA as Light Concentrators

The Schiff base N,N-bis(salicylidene)-o-phenylenediamine (salophen) was prepared by the condensation of salicylaldehyde with o-phenylenediamine in ethanol solution. Two new Zn(II) and Ni(II) salophen complexes, were synthesized, fully characterized by infrared (IR), 1H NMR spectroscopic measurements, UV–Vis spectra, photoluminescence (PL), and X-ray diffraction (XRD). The prepared complexes were used as phosphors to fabricate complexes/PMMA slab-based luminescent solar concentrators (LSC). The thermal stability of pure and doped PMMA polymer was examined by differential scanning calorimetry. Various parameters such as the optical energy gap, refractive index, AC and DC conductivity, dielectric constant, dielectric loss, Urbach energy, fluorescence quantum yield, and Stokes shift have been calculated and discussed. Optical absorption is carried out in wavelength region 200–900 nm at room temperature before and after the samples have been exposed to sunlight for up to 8 h. Photodegradation studies showed that the Zn(II) complex/PMMA LSC has the lowest rate of degradation compared with Ni(II) complex/PMMA LSC with the same concentration (0.06% weight). I–V characteristics of the photovoltaic devices with and without collectors were examined. The PV cell coupled with LSC shows an increase in maximum efficiency by about 50% compared to the normal one. This indicates that the proposed technique is very useful for improving the efficiency of solar cells.

Design of a color neutral non‐patterned photovoltaic window based on luminescent solar concentrator

The necessity to fulfil buildings energy demand with different energy sources lead to an increasing integration between building components and renewable energy sources. The development of new BIPV technologies requiring less silicon solar cells for active area is particularly interesting especially from a circular economy perspective. This work describes the design of five neutral color photovoltaic windows based on large area (0.61 m2) luminescent solar concentrators, which were developed by the University of Ferrara and Eni S.p.A and were installed at the Eni “Renewable, New Energies and Material Science Research Centre” in Novara (Italy). The prototypes show a visible transmittance of 38.5% which represents an improvement with respect to commercial semi‐transparent photovoltaic technologies, moreover the evaluation of the window colorimetric properties highlights a color rendering index equal to 93.0, thus ensuring an excellent illumination quality of the building indoor. The panel electrical performance was measured indoor, at the end of the assembly process, and on‐site, showing a power production ranging from 1.2 W to 2.8 W and an efficiency between 0.23% and 0.48% depending on the illumination condition and the background reflectivity. Although the generated power is limited, it is already sufficient to power stand‐alone small appliances and smart systems.This article is protected by copyright. All rights reserved.

Silver-doped CdSe magic-sized nanocrystals.

Magic-sized nanocrystals (MSNCs) grow via jumps between very specific sizes. This discrete growth is a possible avenue toward monodisperse nanomaterials that are completely identical in size and shape. In spite of this potential, MSNCs have seen limited study and application due to their poor optical properties. Specifically, MSNCs are limited in their range of emission wavelengths and commonly exhibit poor photoluminescence quantum yields (PLQYs). Here, we report silver doping of CdSe MSNCs as a strategy to improve the optical properties of MSNCs. Silver doping leads to controllable shifts in emission wavelength and significant increases in MSNC PLQYs. These results suggest that doped MSNCs are interesting candidates for displays or luminescent solar concentrators. Finally, we demonstrate that the doping process does not affect the magic size of our MSNCs, allowing further photophysical study of this class of nanomaterial.

Engineering Highly Emissive Tetra(t‐Butyl)rubrene/off‐Stoichiometry Thiol‐Ene Hybrids Toward Flexible Luminescent Solar Concentrator‐Integrated Photovoltaics with Excellent Stability

Luminescent solar concentrators (LSCs) are highly valued in transparent photovoltaics for their versatility and adaptability as effective large‐area sunlight collectors. However, constructing LSCs as efficient, long‐term stable, and easily malleable power‐generating units still remains a challenge. Herein, high photostability, high photoluminescence quantum yield (ΦPL), and Stokes‐shifted emission are achieved in tetra(t‐butyl)rubrene/off‐stoichiometry thiol‐ene (TBRb/OSTE) hybrids by incorporating TBRb molecules into OSTE polymers. To demonstrate their potentials in LSCs, a luminescent solar concentrator integrated photovoltaics (LSCIPV) is created using a one‐step synthesis that combines the preparation of TBRb/OSTE hybrids, coupling with the silicon solar cell, and the encapsulation of both components. The LSCIPV demonstrates remarkable flexibility and the integration of an ethylene tetrafluoroethylene film contributes to a hydrophobic surface and antireflection effect, resulting in an external photon efficiency (ηext) of 4.9% and a power conversion efficiency of 1.04% for the 100 cm2 device. The LSCIPV exhibits good photostability over 800 h of UV light exposure. Monte Carlo ray‐tracing simulations indicate that an optimized TBRb‐based LSCIPV can potentially achieve an ηext of 1.3%, even for a large device with an area of 1 m2.

Efficient White-Light Visible Light Communication With Novel Optical Antennas Based on Luminescent Solar Concentrators

Efficient White-Light Visible Light Communication With Novel Optical Antennas Based on Luminescent Solar Concentrators

Harnessing the Synergetic Effects of Ag, Mn Dopants in Eco-Friendly Ultraviolet Selective Quantum Dots for Luminescent Solar Concentrators.

Quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs), yet most QD-based LSCs suffer from toxic metal composition and color tinting. UV-selective harvesting QDs can enable visible transparency, but their development is restricted by large reabsorption losses and low photoluminescence quantum yield (PLQY). The developed here Ag, Mn: ZnInS2/ZnS QDs show a high PLQY of 53% due to the passivating effect of ZnS shell. These QDs selectively absorb UV light and emit orange-red light with a large Stokes shift of 180nm. A LSC of 5×5×0.2cm3, fabricated using a poly(lauryl methacrylate) (PLMA) as a matrix, maintains 87% of integrated PL after 7h of UV exposure. The QD-PLMA achieved 90.7% average visible transparency (AVT) and a color rendering index (CRI) of 95.8, which is close to plain PLMA (AVT=90.8%; CRI=99.5), yielding excellent visible light transparency. Incorporating Si-PVs at LSC edges, the Ag, Mn: ZIS/ZnS QD-LSC achieved an optical efficiency of 1.42%, ranking competitively among high-performing UV-harvesting LSCs.

Semi-Transparent Luminescent Solar Concentrators Based on Intramolecular Energy Transfer in Polyurethane Matrices.

Luminescent solar concentrators (LSCs) are spectral conversion devices offering interesting opportunities for the integration of photovoltaics into the built environment and portable systems. The Förster-resonance energy transfer (FRET) process can boost the optical response of LSCs by reducing energy losses typically associated to non-radiative processes occurring within the device under operation. In this work, a new class of FRET-based thin-film LSC devices is presented, in which the synthetic versatility of linear polyurethanes (PU) is exploited to control the photophysical properties and the device performance of the resulting LSCs. A series of luminescent linear PUs are synthesized in the presence of two novel bis-hydroxyl-functionalized luminophores of suitable optical properties, used as chain extenders during the step-growth polyaddition reaction for the formation of the linear macromolecular network. By synthetically tuning their composition, the obtained luminescent PUs can achieve a high energy transfer efficiency (≈90%) between the covalently linked luminophores. The corresponding LSC devices exhibit excellent photonic response, with external and internal photon efficiencies as high as ≈4% and ≈37%, respectively. Furthermore, their optimized power conversion efficiency combined with their enhanced average visible-light transmittance highlight their suitability for potential use as transparent solar energy devices.

The Emerging Star of Carbon Luminescent Materials: Exploring the Mysteries of the Nanolight of Carbon Dots for Optoelectronic Applications.

Carbon dots (CDs), a class of carbon-based nanomaterials with dimensions less than 10nm, have attracted significant interest since their discovery. They possess numerous excellent properties, such as tunability of photoluminescence, environmental friendliness, low cost, and multifunctional applications. Recently, a large number of reviews have emerged that provide overviews of their synthesis, properties, applications, and their composite functionalization. The application of CDs in the field of optoelectronics has also seen unprecedented development due to their excellent optical properties, but reviews of them in this field are relatively rare. With the idea of deepening and broadening the understanding of the applications of CDs in the field of optoelectronics, this review for the first time provides a detailed summary of their applications in the field of luminescent solar concentrators (LSCs), light-emitting diodes (LEDs), solar cells, and photodetectors. In addition, the definition, categories, and synthesis methods of CDs are briefly introduced. It is hoped that this review can bring scholars more and deeper understanding in the field of optoelectronic applications of CDs to further promote the practical applications of CDs.

A Multistate Thermoresponsive Smart Window Based on a Multifunctional Luminescent Solar Concentrator.

Conventional luminescent solar concentrators (LSCs) usually only have the ability to absorb solar energy and convert it to electricity but are not able to regulate the transmitted light. Herein, a multistate thermoresponsive smart window (SW) based on LSC has been fabricated, in which the stimuli-responsive host layer consists of polydimethylsiloxane (PDMS) and ethylene glycol solution (EGS) microdroplets stacking with LSC layer-based on near-infrared (NIR) CuInSe2-xSx/ZnS core/shell quantum dots (QDs) and PDMS matrix. As-synthesized CISSe/ZnS QDs with broad NIR absorption in LSC exhibit controllable emission spectra over 833-1088 nm and high photoluminescence (PL) quantum yield from 45 to 83%. Coupling with Si solar cells as a reference, optimized LSC-SW devices with dimensions of 5 × 5 × 0.9 cm3 exhibit higher power conversion efficiency (PCE) of 1.19-1.36% with increased temperature from 0 to 50 °C than those of sole LSC and SW devices. The corresponding visible light transmissions are regulated from 75.1 to 48.1% accordingly. The improvement of PCEs in an opaque state is mainly due to enhanced absorption of QDs originating from rescattered photons from the EGS/PDMS layer, leading to more emitted photons reaching photovoltaics. This work is expected to bring up new opportunities for applications in greenhouses, building facades, and energy-efficient smart windows.

Luminescent Solar Concentrator with Advanced Structure for Reabsorption Loss Suppression and Synergistic Energy Harvesting

AbstractAs large‐area and optically transparent photon harvesting devices, luminescent solar concentrators (LSCs) are promising candidates for building‐integrated photovoltaics owing to their high transmittance and resistance to shadowing effects existing in solar cells. Up to now, there are still many challenges in the practical application of LSCs: 1) Reabsorption loss is inevitable during photoluminescence transmission due to indirect illumination of solar cells in LSC system. 2) Satisfactory energy harvesting cannot be achieved in rainy conditions due to the substantial attenuation of the incident light intensity. 3) Evaporation residue on the surface of LSCs leads to device performance degradation. Pioneering researches and feasible strategies for reabsorption loss suppression, energy harvesting in rainy days as well as self‐cleaning property are still lacking demonstration. In this work, reabsorption loss is suppressed based on advanced structural LSCs with universally applicable optical spacer layer. Then the integrated LSCs with droplet‐based electricity generator (DEG) are proposed for the first time. Such DEG‐LSCs not only realize synergistic harvesting of solar and raindrop energy, but also possess self‐cleaning properties. Finally, a self‐powered temperature and humidity sensing system is designed and demonstrated to provide feasible ideas for the practical application of DEG‐LSCs in self‐powered intelligent buildings.

Predicting the efficiency of luminescent solar concentrators for solar energy harvesting using machine learning

Building-integrated photovoltaics (BIPV) is an emerging technology in the solar energy field. It involves using luminescent solar concentrators to convert traditional windows into energy generators by utilizing light harvesting and conversion materials. This study investigates the application of machine learning (ML) to advance the fundamental understanding of optical material design. By leveraging accessible photoluminescent measurements, ML models estimate optical properties, streamlining the process of developing novel materials, offering a cost-effective and efficient alternative to traditional methods, and facilitating the selection of competitive materials. Regression and clustering methods were used to estimate the optical conversion efficiency and power conversion efficiency. The regression models achieved a Mean Absolute Error (MAE) of 10%, which demonstrates accuracy within a 10% range of possible values. Both regression and clustering models showed high agreement, with a minimal MAE of 7%, highlighting the efficacy of ML in predicting optical properties of luminescent materials for BIPV.

Photoluminescence of combinatorically sputtered Al2O3–Y2O3 thin films with a Cr3+ and Nd3+ co-doping concentration gradient

The characterization of a wide range of luminescent thin films can be a long and tedious endeavor. With reactive combinatorial sputtering of multiple metal targets, it possible to fabricate thin films with a gradient in composition simply by not rotating the substrate. In this work, combinatorically sputtered thin films of Cr3+ and Nd3+ doped in the Al2O3–Y2O3 system (YAlO) are studied for thin film based luminescent solar concentrators (TFLSCs) application. Contrary to mm's thick plate type LSC's, TFLSCs of just several 100 nm thick require much higher Cr3+ concentration to achieve 40% absorption which can enable several 10's of W/m2 LSC power efficiencies. Our transmission measurements on a Cr2O3 film with a thickness gradient result in an absorption cross section at 460 nm of 1.3 ± 0.7 × 10−19 cm2 showing that the TFLSC absorption requirement can be fulfilled provided that the Cr3+ concentration is in the order of 1022 ions/cm3. The Y:Al ratio of the YAlO host in our films ranged between 0.5 and 3.5, thereby including the monoclinic (Y4Al2O9), perovskite (YAlO3) and garnet (Y3Al5O12) stoichiometry's on a single film. Position dependent XRD, EDX, excitation, emission and lifetime measurements of Cr3+ and Nd3+ show that the unique gradient film sputtering method is able to characterize thin films as a function of host composition and doping concentration. Energy transfer between Cr3+ and Nd3+ in co-doped YAlO films is concluded from Cr3+ excitation bands observed while monitoring Nd3+ emission and from the matching of the rise-time of Nd3+ 1340 nm emission (4F3/2 ->4I11/2) and the decay time of Cr3+ 840 nm emission (4T2 ->4A2). Nd3+ lifetime systematically decreases from 0.24 to 0.05 ms with increasing Cr3+ concentration in Y3Al5-xCrxO12:Nd (0.05 < x < 2). The constraints of heavily doped Cr3+ thin films for enabling adequate absorption and energy transfer to Nd3+ in TFLSC applications are the subjects of the discussion.

Revealing the potential of luminescent solar concentrators in real-world environments

Revealing the potential of luminescent solar concentrators in real-world environments

Certification Grade Quantum Dot Luminescent Solar Concentrator Glazing with Optical Wireless Communication Capability for Connected Sustainable Architecture

AbstractEnergy sustainability and interconnectivity are the two main pillars on which cutting‐edge architecture is based and require the realization of energy and intelligent devices that can be fully integrated into buildings, capable of meeting stringent regulatory requirements and operating in real‐world conditions. Luminescent solar concentrators, particularly those based on near‐infrared emitting reabsorption‐free quantum dots, are considered good candidates for the realization of semi‐transparent photovoltaic glazing, but despite important advances in optical property engineering strategies, studies of finished devices suitable for real‐world operation are still lacking. In this paper, the first example of a fully assembled quantum dot luminescent solar concentrator‐based photovoltaic glazing is demonstrated that meets all international standards for photovoltaic and building elements. It is also shown that these devices are capable of functioning as efficient Visible Light Communication (VLC) receivers even under full sunlight, thus combining energy and wireless connectivity functions in a realistic solution for smart, sustainable buildings.

A Comprehensive Review on Mechanisms and Applications of Rare‐Earth Based Perovskite Nanocrystals†

Comprehensive SummaryRare earth (RE) ions, with abundant 4f energy level and unique electronic arrangement, are considered as substitutes for Pb2+ in perovskite nanocrystals (PNCs), allowing for partial or complete replacement of lead and minimizing environmental impact. This review provides a comprehensive overview of the characteristics of RE‐doped PNCs, including up‐conversion luminescence, down‐conversion luminescence, and quantum confinement effects, etc. Additionally, RE doping has been found to effectively suppress defect formation, reduce nonradiative recombination, enhance photoluminescence quantum yield (PLQY), and even allow for controlling over the morphology of the nanocrystals. The review also highlights the recent advancements in lead‐free RE‐based perovskites, especially in the case of Eu‐based perovskites (CsEuBr3 and CsEuCl3). Furthermore, it briefly introduces the applications of PNCs in various fields, such as perovskite solar cells (PSCs), luminescent solar concentrators (LSCs), photodetectors (PDs), and light‐emitting diodes (LEDs). A systematic discussion on the luminescence mechanisms of RE‐doped PNCs and lead‐free RE‐based perovskites is provided, along with an outlook on future research directions. The ultimate goal of this review is to provide guidance for the development of RE‐based perovskite optoelectronic devices. Key ScientistsIn 2015, Kovalenko et al. pioneered the synthesis of lead‐based perovskite nanocrystals using the thermal injection method. Concurrently, Zhong et al. introduced the ligand‐assisted reprecipitation method. These methods have become the predominant approaches for fabricating lead‐based perovskite nanocrystals. In 2017, Song et al. successfully incorporated various rare earth ions (Ce3+, Sm3+, Eu3+, Tb3+, Dy3+, Er3+, and Yb3+) into CsPbCl3 perovskite nanocrystals. They also observed the quantum cutting effect induced by defect states, facilitated by the doping of Yb3+. Gamelin et al. subsequently proposed that CsPbCl3:Yb3+ nanocrystals exhibit quantum cutting effects due to the introduction of charge‐compensating defects (VPb), resulting in the formation of Yb3+‐VPb‐Yb3+ defect complexes with shallow defect levels. In 2020, Zhang et al. successfully doped Nd3+ into CsPbBr3, yielding blue luminescent nanocrystals with a central wavelength of 459 nm and up to 90% photo‐luminescence quantum yield (PLQY). In the same year, Yang et al. achieved the synthesis of pure phase CsEuCl3 perovskite nanocrystals for the first time. In 2022, Paik et al. synthesized Cs3LnCl6 (Ln = Y, Ce, Gd, Er, Tm, Yb, Eu, Tb) nanocrystals using the thermal injection method. In 2023, Zhang et al. successfully introduced Ni2+ doping into CsEuCl3, enhancing the PLQY of CsEuCl3 nanocrystals from 5% to 19.7%. This review focuses on the development history of perovskite nanocrystals, including rare earth‐doped lead‐based perovskite nanocrystals and rare earth‐based lead‐free perovskite nanocrystals, as well as their applications.

Engineering of Multidimensional Core-Shell Perovskite Precursors to Obtain Superior Luminescence and Incorporating in Luminescent Solar Concentrators

The luminescence feature of perovskite NPs with high PLQY directs them to lighting and display applications. 2D A2MAn−1PbnBr3n+1 (n=1−6) perovskites with A as octylammonium and benzylammonium cations are synthesized by the LARP method, in which the highest PL emission is attained to the n=6 sample with benzylamine cation. XRD results reveal the appearance of diffraction peaks related to 3D perovskites with increasing n value. Mixing 3D perovskites with 2D ones leads to the formation of core-shell MAPbBr3−A2MAn−1PbnBr3n+1 (n=1−6) nanostructures, confirmed by TEM images and optical properties. Incorporation of Zn to core-shell perovskites improves the PL intensity and induces higher crystallinity. A blue shift in absorption and emission spectra of Zn-doped perovskites is observed. The highest PLQY (94%) is attributed to the Zn-doped core-shell perovskite with n=6 among the all-synthesized samples. Luminescent solar concentrators with thicknesses of 2 mm and 5 mm are fabricated with benzylamine-based perovskites, because of their greater PLQY versus octylamine-based perovskites. The performance of LSC devices is boosted for the LSC with 5 mm thickness. The relative PCE obtained for the core-shell perovskite-based LSC with thickness of 5 mm reaches to almost 60%.

All-inorganic luminescent solar concentrator based on transparent multicomponent glasses embedded with PbSe QDs

Luminescent solar concentrators (LSCs) have become a seminal technology with the possibility of producing carbon–neutral buildings. However, current LSCs developed based on organic or organic–inorganic strategies face limited long-term outdoor stability. Here we developed an inorganic PbSe QDs glass with a strong UV absorption, large Stokes shift, broadband excitation and emission, and high transparency in the visible range. In addition, the suitability of inorganic PbSe quantum dots (QDs) glasses for use in LSCs as both transparent matrix and luminophore, as an alternative to the combination scheme of organic dyes or colloidal QDs and organic polymer materials was explored. Coupled with a commercial silicon solar cell, the as-prepared transparent LSC exhibited an optical efficiency of 10.13 % and a power conversion efficiency of 1.59 % under standard sunlight. These results demonstrate a new strategy to fabricate stable all-inorganic transparent LSCs for building integrated photovoltaic systems.

Controllable and large-scale synthesis of carbon quantum dots for efficient solid-state optical devices

Carbon quantum dots (C-dots) showed excellent structure-tunable optical properties, mainly composed of carbon, nitrogen and oxygen. They have been used for various types of solid-state optical devices. Due to the photoluminescence quenching caused by aggregation, it is a challenge to produce high quantum yield and large Stokes shift C-dots via controllable and simple approaches. In this work, we demonstrated a microwave assisted heating approach for the high-quality C-dots production with ten grams scale per batch in less than 4 min. The addition of metal cation promoted the formation of the foam-structure by forming carboxyl-metal-amine complex, enabling the spatial confined growth of the C-dots in a solid-state, contributing to the high quantum yield (QY) of 73% with a Stokes shift of 0.65 eV. By tuning the structure of the C-dots, excitation dependent and independent photoluminescent (PL) behavior were achieved because of the formation of the different types of energy states evidenced by transient PL and femtosecond transient absorption spectroscopy. These optical properties enable the C-dots to be successfully integrated in luminescent solar concentrators (LSCs), having an external optical efficiency of 3.0% and a power conversion efficiency of 1.3% (225 cm2) and an excitation-dependent high-level anticounterfeiting fluorescent code, showing a great potential for solid-state optical system.

Photoluminescence lifetime stability studies of β-diketonate europium complexes based phenanthroline derivatives in poly(methyl methacrylate) films.

In this work, five phenanthroline derivatives substituted with different methyl groups have been selected to synthesize β-diketonate-based europium complexes to check the influence of the substitutions on the degradation effect of those complexes in poly(methyl methacrylate) (PMMA) films. The photophysical properties of Eu(III) complexes, including absorbance, excitation, and emission have been carefully investigated in solution, solid-state, and doped in PMMA film. In all these states, the complexes exhibit an impressive red emission at 614 nm with a high photoluminescence quantum yield of up to 85 %. The films have been exposed under outdoor, indoor, and dark storage stability lifetime conditions for 1200 hours. The photoluminescence measurements recorded every 400, 800, and 1200 hours demonstrated that the film containing europium complex with phenanthroline ligand substituted by a high number of methyl groups (Eu(TTA)3L5) showed good photoluminescent stability in indoor and dark conditions, and exhibited better resistance to degradation in outdoor conditions compared to other complexes. This study has proved that phenanthroline ligands could be tuned chemically leading to better stability of those types of complexes in films which can be end-used for future stable optoelectronic devices such as luminescent solar concentrators.

RETRACTED ARTICLE: Luminescent solar concentrator efficiency enhanced via nearly lossless propagation pathways

Luminescent solar concentrators (LSCs) have the potential to serve as energy-harvesting windows in buildings. Although recent advances in nanotechnology have led to the emergence of novel fluorophores such as quantum dots, perovskites and others, the commercialization of such functional glass remains immature due to an insufficient power conversion efficiency. In other words, improvements in fluorophores alone cannot fully maximize the potential of LSCs. Here we introduce a new laminated type of LSC structure where a patterned low-refractive-index medium acts as an optical ‘guard rail’, providing a practically non-decaying path for guiding photons. We also propose the design rules regarding the dimensions of LSCs and the spectral characteristics of fluorophores. Once these rules were applied, we achieved record-high LSC performance. The measured external quantum efficiencies at 450 nm are 45% for a 100 cm2 area and 32% for the LSC with an edge aspect ratio of 71. The device efficiency is 7.6%, the highest value ever reported, to the best of our knowledge. These findings may have industrial implications and could accelerate the commercialization of LSCs.