FIG 1 - uploaded by Jan Christoph Goldschmidt
Content may be subject to copyright.
͑ Color online ͒ Working principle of the fluorescent concentrator. The fluorescent concentrator consists of a transparent matrix material in which a fluorescent dye is included. Light in a certain spectral range is absorbed by the dye and reemitted at a higher wavelength ͑ Stokes shift ͒ . Because of TIR a part of the light is internally transported to the edges of the concentrator, where it is used by solar cells. In this sketch the solar cell is shown only at one side of the concentrator, typically all four sides are covered.
Source publication
It is possible to increase the efficiency of fluorescent concentrator systems with photonic structures. This is achieved by reducing the losses caused by the loss cone of total internal reflection. Examples of fluorescent concentrators we are currently working with are given and different photonic structures designed for the application on these fl...
Context in source publication
Context 1
... structures can be used to increase the efficiency of the internal light transport in a fluorescent concentrator and therefore the system efficiency of a solar fluorescent concentrator system. In this study we show fluorescent concentrator systems that are recently used for experiments and different photonic structures designed for the application of these filters first. Ideal filter systems are presented as well as real filters. The example filters given are the rugate filter, the band edge filter, and the opal, a three dimensional photonic crystal. According to our experience made in initial experiments, the required quality of the filters is not obvious. Therefore, the aim of this study is to develop a method to perform theoretical predictions of the effects of these filters and to compare the simulated results with the experimentally obtained ones. For this task a method of analysis is set up that takes into account the gain of the light guiding efficiency and losses caused by unwanted reflections. With the help of this method principal considerations on the demands of the filters are given and a detailed analysis of the presented systems of fluorescent concentrators and photonic structures is performed. In Sec. II a short introduction into fluorescent concentrators is given and the main loss mechanism of these concentrators is sketched. Examples for fluorescent concentrators recently used in experiments are given and the concept of how to eliminate the loss cone losses by the application of a photonic structure is described. In Sec. III a short introduction into photonic crystals is given. Different photonic structures are shown that are designed especially for the application on a certain fluorescent concentrator. In Sec. IV the analysis method to investigate the effects on the light guiding efficiency of the photonic structures is presented. Consider- ations about the demands of the filters and geometrical effects are given. The different filters are analyzed in detail. The results of this analysis are discussed in Sec. V. A fluorescent concentrator consists of a transparent material in which a dye is included. The dye absorbs light from a certain spectral absorption range and emits light into an- other spectral range, the photoluminescence range. This photoluminescence range is spectrally shifted to the red compared to the absorption range ͑ Stokes shift ͒ . The emission characteristic is omnidirectional so that a fraction of the light is emitted into an angular range where total internal reflection ͑ TIR ͒ occurs. Because of the Stokes shift, reabsorption of the emitted light is much less probable than an absorption event. In that way the light emitted into the angular range of TIR is transported to the edges of the concentrator almost undisturbed. Here a solar cell can use the concentrated light. A concentration occurs because the area on the top of the concentrator, through which light is absorbed, is larger than the area at the edges. The working principle of the fluorescent concentrator is sketched in Fig. 1. The subject of fluorescent concentrators for solar cell applications has been explored intensively in the late 1970s 1 and early 1980s. The idea of the concept by then was to replace expensive solar cell area by potentially cheap syn- thetic materials. No sufficient efficiencies where achieved though and the scientific interest in the subject dropped. The reasons for the moderate efficiencies of the fluorescent concentrators are found in several loss mechanisms. These loss mechanisms reduce the internal light guiding efficiency of the system and therefore the amount of light reaching the solar cell. The most important loss mechanism is the loss through the loss cone of TIR Fig. 2 . Only light emitted into an angular range with angles greater than a critical angle c is totally internally reflected. The critical angle is given ...
Similar publications
Two Dimensional (2D) circular Photonic Crystal Ring Resonator (PCRR) based Add Drop Filter (ADF) is designed and the impacts of rod shape with its filling fraction is examined to evaluate the performance of the filter. The ADFs are devised separately using rods of circular, hexagonal and square shape in square lattice PC. For various values of rod'...
In the present study, we show that it is possible to achieve multi-channel filters in one-dimensional photonic crystals using photonic quantum well structures. The photonic quantum well structure consists of different 1-D photonic structures. We use (AB) 8 /C n /(BA) 8 structure, where A, B and C are different materials. The number of defect layers...
In this paper it has been reported that the
insertion loss is improving and return loss is maximizing
due to the effect of photonic band gap structure. Using
photonic band gap structure on the filter surfaces have been
provided information about the increasing bandwidth up to
30% of band stop filters. To use of the PBG filters, the
broad stop band...
The silicon-on-insulator (SOI) material system is today widely recognized as one of the most important platforms for the development of photonic components. This is mainly due to the fact that the mass fabrication techniques of the CMOS technology can
Fe3O4 nanoparticles fluid has unique optical properties, which provides versatile possibilities to design state-of-the-art photonic devices. In this paper, by combining Fe3O4 nanoparticles fluid with the photonic crystal fiber (PCF), the spectral characteristics of fluid-filled PCF under different temperatures were experimentally demonstrated. Tran...
Citations
... Under certain exciting conditions, PCs can support guided mode resonances that can channel internal light externally [82]. Such processes have been exploited to increase the emission collection efficiency, as demonstrated in Figure 1e [96][97][98]. ...
Nanoscale fluorescence emitters are efficient for measuring biomolecular interactions, but their utility for applications requiring single-unit observations is constrained by the need for large numerical aperture objectives, fluorescence intermittency, and poor photon collection efficiency resulting from omnidirectional emission. Photonic crystal (PC) structures hold promise to address the aforementioned challenges in fluorescence enhancement. In this review, we provide a broad overview of PCs by explaining their structures, design strategies, fabrication techniques, and sensing principles. Furthermore, we discuss recent applications of PC-enhanced fluorescence-based biosensors incorporated with emerging technologies, including nucleic acids sensing, protein detection, and steroid monitoring. Finally, we discuss current challenges associated with PC-enhanced fluorescence and provide an outlook for fluorescence enhancement with photonic-plasmonics coupling and their promise for point-of-care biosensing as well monitoring analytes of biological and environmental relevance. The review presents the transdisciplinary applications of PCs in the broad arena of fluorescence spectroscopy with broad applications in photo-plasmonics, life science research, materials chemistry, cancer diagnostics, and internet of things.
... This has been primarily due to the lack of high quantum yield luminophores and poor waveguiding efficiency of luminesced photons. With the recent developments of near unity quantum yields with large Stokes shifts in quantum dots (Hanifi et al., 2019), the focus has shifted to photon management to effectively guide photoluminescence to the edges (Peters et al., 2009;Verbunt et al., 2013). Initial LSC designs relied solely on total internal reflection for photoluminescence waveguiding which can theoretically achieve trapping efficiencies over 90% (Mulder et al., 2010). ...
Despite the extraordinary advances in solar cell efficiency in laboratory settings, the deployment of solar cells continues to be limited to low efficiency (<25%) silicon cells because of cost. In this work, we take advantage of the extraordinary optical properties afforded by nanophotonic structures to create a photonic luminescent solar concentrator for an InGaP-Si multijunction concentrator cell. Finite difference time domain (FDTD) simulations demonstrated a concentrator that could effectively capture, downconvert, and guide concentrated light to an InGaP subcell while still transmitting longer wavelengths to a Si subcell. We fabricated the photonic luminescent solar concentrator, which was comprised of CdSe/CdS quantum dots embedded within alternating layers of Si3N4 and SiO2, and experimentally verified the optical performance, showing a 40% increase in light guiding and a significant reduction in reabsorption losses in the plane of the luminescent concentrator as compared to traditional designs. Finally, we utilized modified detailed balance calculations that accounted for cell and optical losses and showed >30% efficiencies are possible with this design, demonstrating the potential to meet the demands for high efficiency, inexpensive solar modules.
... Spectrally selective filters for PV concepts with luminescent materials are another class of filters designed for improving the efficiency of solar cells by using fluorescent concentrators and fluorescent concentrators with upconversion. For fluorescent concentrators, the filter reflects the light in the escape cone and transports it to the edges where cells are located [15]. ...
The cooling of photovoltaic panels plays an important role in improving electrical efficiency and increasing the lifetime. In this paper, a radiation shield for filtering the thermal part of solar irradiance has been proposed as a passive cooling method. A 3D model of a PV module with all consisting layers has been numerically simulated. The radiative transfer equation has been solved by discrete ordinates (DO) method. The numerical results of the uncooled PV module have been compared with the experimental data. The radiation shields with 40% and 80% reflections in the wavelength interval between 1 μm and 2.4 μm have been performed to reduce the thermal effect of solar irradiation over the PV module. The effects of radiation shield on the instantaneous and monthly average surface temperature of the PV module have been investigated. It has been found that the effect of radiation shield on temperature reduction of the PV module is more considerable in seasons with high solar irradiation. The numerical results show that the radiation shield with 80% reflectivity has more effect on temperature reduction and the electrical efficiency of the PV module. The numerical results reveal that, for solar irradiation between 1025 and 1142 W/m2, the radiation shield with 80% reflection can increase the electrical efficiency by about 5.14%–5.72%.
... After about 4 decades of progress in the development of solar cells and luminescent materials, and with new concepts, several groups such as those of Refs. van Roosmalen (2004); van Sark et al. (2008); Luque et al. (2005); Goldschmidt et al. (2006); Richards and Shalav (2005); Richards et al. (2004); Rau et al. (2005); Glaeser and Rau (2006); Goldschmidt et al. (2007); Danos et al. (2006); Debije et al. (2007); Slooff et al. (2007); Slooff et al. (2008); Chatten et al. (2003a); Chatten et al. (2001); Chatten et al. (2003b); Goldschmidt et al. (2008); Peters et al. (2009); Goldschmidt et al. (2009a); ten Kate et al. (2015); Meinardi et al. (2017a); McKenna and Evans (2017); Traverse et al. (2017); Klimov et al. (2016); Bauser et al. (2020); Aghaei et al. (2020), are currently reinvestigating the potential of luminescent concentrators, mainly including nanocrystals in the matrix. High efficiencies have been achieved Goldschmidt et al., 2009a;ten Kate et al., 2015) and there has also been considerable progress in the understanding and theoretical description (for example, Chatten et al., 2003b;Peters et al., 2009;Goldschmidt, 2009;Peters et al., 2010;Peters, 2009). ...
... van Roosmalen (2004); van Sark et al. (2008); Luque et al. (2005); Goldschmidt et al. (2006); Richards and Shalav (2005); Richards et al. (2004); Rau et al. (2005); Glaeser and Rau (2006); Goldschmidt et al. (2007); Danos et al. (2006); Debije et al. (2007); Slooff et al. (2007); Slooff et al. (2008); Chatten et al. (2003a); Chatten et al. (2001); Chatten et al. (2003b); Goldschmidt et al. (2008); Peters et al. (2009); Goldschmidt et al. (2009a); ten Kate et al. (2015); Meinardi et al. (2017a); McKenna and Evans (2017); Traverse et al. (2017); Klimov et al. (2016); Bauser et al. (2020); Aghaei et al. (2020), are currently reinvestigating the potential of luminescent concentrators, mainly including nanocrystals in the matrix. High efficiencies have been achieved Goldschmidt et al., 2009a;ten Kate et al., 2015) and there has also been considerable progress in the understanding and theoretical description (for example, Chatten et al., 2003b;Peters et al., 2009;Goldschmidt, 2009;Peters et al., 2010;Peters, 2009). However, efficiencies are still too low and system sizes too small for a commercial application, while some 41 m 2 system sizes have been realized and tested (Kanellis et al., 2017;Corrado et al., 2016). ...
A luminescent solar concentrator consists of a waveguide collector and solar cells connected to the waveguide sides or bottom. Luminescent centers, such as organic dye molecules and nanoparticles absorb incoming photons and emit red-shifted photons that are mostly trapped inside the waveguide due to total internal reflection and finally coupled out into the solar cells, where they are converted into electricity. Typical designs lead to concentration of both direct and diffuse light. This chapter describes the theoretical principles of the luminescent solar concentrator and discusses factors that determine the overall device efficiency. Also, various choices for luminescent materials are detailed as well as various designs and experimental results. The future application area can be wide, ranging from greenhouses to building integrated photovoltaics, in which transparent energy-generating windows could contribute to energy neutrality of buildings.
... OF PHOTONIC CRYSTAL WAVEGUIDES Guided modes in photonic crystal waveguides (PCWGs) have been extensively studied and experimentally realized for applications in magnetic mode control, non-linear optics, high quality resonators, on-chip photonic lasers, and LSCs. [21][22][23][24][25][26][27][28] PCWGs are capable of guiding emitted light into waveguide modes thus increase the optical efficiency of waveguides for LSCs. For the purposes of light trapping in LSCs, we consider the 2-D PCWG that is periodic in the x and y plane with a defined thickness, t, in the z plane. ...
Luminescent solar concentrators are currently limited in their potential concentration factor and solar con-version efficiency by the inherent escape cone losses present in conventional planar dielectric waveguides. We demonstrate that photonic crystal slab waveguides tailored for luminescent solar concentrator applica-tions can exhibit >90% light trapping efficiency. This is achieved by use of quantum dot luminophores em-bedded within the waveguide that absorb light at photon energies corresponding to photonic crystal leaky modes that couple to incoming sunlight. The luminophores then emit at lower photon energies into photon-ic crystal bound modes that enable highly efficient light trapping in slab waveguides of wavelength-scale thickness. Photonic crystal waveguides thus nearly eliminate escape cone losses, and overcome the perfor-mance limitations of previously proposed wavelength-selective dielectric multilayer filters. We describe de-signs for hole-array and rod-array photonic crystals comprised of hydrogenated amorphous silicon carbide using CdSe/CdS quantum dots. Our analysis suggests that photonic crystal waveguide luminescent solar con-centrators using these materials these can achieve light trapping efficiency above 92% and a concentration factor as high as 100.
... La seconde école cherchera plus à diriger les rayons dans une direction privilégiée. Pour cela, une solution proposée dans la littérature (Peters et al. 2009) consiste à mettre une structure photonique de part et d'autre du concentrateur pour guider la lumière préférentiellement dans une direction (voir Figure A6 -2). En faisant cela, les auteurs ont réussi à augmenter le flux en sortie de la face considérée de 20%. ...
... Structure photonique proposée par(Peters et al. 2009) amenant la lumière vers la cellule photovoltaïque. Première observation de l'électroluminescence(Round 1907). ...
Depuis le début des années 2000, les performances des diodes électroluminescentes (LED) ne cessent de s’améliorer alors que leur prix connait une diminution spectaculaire grâce à une production à grande échelle liée au marché de l'éclairage. Ainsi, les LED deviennent une source de lumière intéressante pour le pompage de lasers solides, intermédiaire entre les lampes flash et les diodes laser. C’est pourquoi, nous proposons dans cette thèse, de revisiter le pompage laser par LED, 40 ans après la première démonstration. Nous avons démontré le premier système laser Nd:YVO4 pompé directement par LED. La brillance des LEDs limitant fortement les performances, nous nous sommes intéressé au concept de concentrateur luminescent (en Ce:YAG) pompé par LED. Nous avons ainsi développé une nouvelle source d’éclairage haute brillance, améliorant les performances des LEDs d’un facteur 20 pour aboutir à des éclairements comparables à ceux des diodes laser (de l’ordre de plusieurs kW/cm²). Le pompage laser par cette nouvelle source de pompage a été validé pour la première fois sur les cristaux laser de Nd:YVO4 (3 mJ obtenus avec un profil monomode et 6 mJ en multimode) ainsi que sur des cristaux de Nd:YAG. Dans ce dernier cas, un déclenchement passif à l’aide d’absorbants saturables a permis d'obtenir ainsi des performances encore jamais atteintes pour un laser pompé par LED. Ainsi, les concentrateurs pompés par LED ouvrent de nouvelles possibilités pour le pompage de matériaux laser nécessitant de forte brillance de pompage. Les premiers essais sur le saphir dopé au titane montrent qu'il est possible d'obtenir du gain sur ce matériau en pompage par LED.
... The embedding of active optical elements into a matrix to focus solar irradiation impinging on a wide top surface onto a side surface which feeds into a solar cell is known from socalled luminescent solar concentrators (LSCs). [23][24][25] While the proposed structure of an ao-HCEC (Fig. 6) may look similar to an LSC at a glance, the ao-HCEC differs in several important aspects. It has aNWs as waveguides for directed transport of emitted hν (vs nano-dots in LSCs), the emitted hν originate from R rad of HCs (vs pure hν conversion in LSCs), and the Stokes shift of emitted hν is negative (vs positive in LSCs to promote hν conversion at the cost of lower energies of emitted hν) since the bandgap of the aNWs is bigger as compared to the HCA. ...
The all-optical hot carrier solar cell (aoHCSC) is an intriguing device concept which circumvents HC thermalization by feeding HCs into local radiative recombination centers. These have transition energies above the HC absorber (HCA) bandgap and are located within the HCA to match the HC ballistic mean free path, suppressing HC cooling as major loss mechanism. HC energy extraction proceeds by photon emission. We propose a technologically feasible concept of the aoHC energy converter (aoHCEC) which feeds into a conventional solar cell with its bandgap matching the emitted photons. Using real materials, the concept builds upon waveguides within a HCA which consist of highly polar direct bandgap material to promote radiative carrier recombination.
... [9][10][11][12][13] While the choice of fluorophores varies between a wide range of organic dyes, semiconducting polymers and quantum dots, the host is usually an inert matrix. [14][15][16][17] Recently, photonic luminescent solar concentrators (PLSCs) have been developed, in which photonic crystal films are externally applied to an LSC to assist in photon management [18,19] by reducing escape cone losses. In this configuration, the photonic films act as reflectors across a particular spectral band, enhancing photon confinement within the device. ...
We have developed organic dye-integrated thin-film liquid crystalline photonic luminescent solar concentrators (LSCs), where the chirality of the liquid crystal (LC) results in the formation of a one-dimensional photonic cavity. By varying the different LSC parameters, including dye concentration, spectral position of the photonic band-gap and the LC phase, and by using spectroscopic and electrical characterisation, we have systematically studied the effects of self-absorption, incident absorption and confinement of down-converted emission on optical efficiency. Our results demonstrate that the efficiency of our LSCs is significantly enhanced in the LC phase when the photonic band-gap is at long wavelengths (>600 nm), overcoming associated low incident absorption and higher self-absorption. We reach the significant conclusion that focusing on improving the confinement of dye-emitted photons, rather than on increasing incident absorption, is a more promising route to enhancing thin-film LC-based LSC performance.
... Simple trigonometric arguments that follow from Fig. 2 allows φ 1 and φ 2 to be determined for emission from a given point in the xy plane as well as the two additional azimuthal angles required for a complete description. Dividing a FSC in the 4Cell setup into such distinct position dependent angular regions for calculating the path length has also been used in [19]. ...
Fluorescent solar concentrators (FSC) can concentrate light onto solar cells by trapping fluorescence through total internal reflection. In an ideal FSC, the major obstacle to efficient photon transport is the re-absorption of the fluorescence emitted. In order to decompose the contribution of different photon flux streams within a FSC, the angular dependent re-absorption probability is introduced and modeled in this paper. This is used to analyze the performance of different FSC configurations and is also compared with experimental results. To illustrate the application of the modeling, the collection efficiency of ideal devices has also been calculated from the re-absorption probability and is shown to be useful for estimating non-ideal losses such as those due to scattering or reflection from mirrors. The results also indicate that among the FSCs studied, the performance of those surrounded by four edge solar cells is close to ideal. The rapid optimization of FSCs has also been presented as another practical application of the models presented in this paper. Copyright © 2014 John Wiley & Sons, Ltd.
... Various optical approaches have been explored to improve LC performance, including different LC shapes and fiber geometries, 15,16 wavelength selective mirrors to reduce escape-cone loss, 17,18 and patterned dye regions with and without primary lenses to reduce reabsorption. 19,20 Alternatively, the opportunity for secondary geometric gain of the luminescence itself was recognized early on, 21 where molding the edge of a typical LC slab in the form of a compound parabolic concentrator enables the output intensity to be increased by a factor β = 1/ sin(90°− θ crit ) since the total internal reflection critical angle, θ crit , naturally limits the angular extent of luminescence reaching the edge. ...
Luminescent and nonimaging optical concentration constitute two fundamentally different ways of collecting and intensifying light. Whereas nonimaging concentrators based on reflective, refractive, or diffractive optics operate most effectively for collimated light, luminescent concentrators (LCs) rely on absorption, re-emission, and waveguiding to concentrate diffuse light incident from any direction. LCs have been explored in many different shapes and sizes but have so far been unable to exploit the power of nonimaging optics to further increase their concentration ratio because their emission is angularly isotropic. Here, we use a luminescent thin film bilayer to create sharply directed conical emission in an LC and derive a nonimaging optical solution to leverage this directionality for secondary geometric gain ranging up to an order of magnitude or higher. We demonstrate this concept experimentally using a custom compound parabolic optical element index-matched to the LC surface and show that it delivers three times more luminescent power to an opposing GaAs photovoltaic cell when the emission profile is conically directed than when it is isotropic or the nonimaging optic is absent. These results open up a significant and general opportunity to improve LC performance for a variety of applications including photovoltaics, photobioreactors, and scintillator-based radiation detection.
