# US 10,872,993 B2 · Visibly transparent, luminescent solar concentrator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,993 B2 - Document ID: US10872993B2 - Status: Granted - Kind: B2 - Application number: 15/967,165 - Filed: 2018-04-30 - Published: 2018-08-30 - Granted: 2020-12-22 - Earliest claimed: 2012-06-13 - Assignees: Massachusetts Institute of Technology - Applicants: Massachusetts Institute of Technology - Inventors: Richard Royal Lunt; Vladimir Bulovic; Miles Clark Barr - Web page: https://patentgrep.com/patent/US10872993B2 ## CPC - H10F 77/45: Wavelength conversion means, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements - Y02E 10/52: PV systems with concentrators - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A visibly transparent luminescent solar concentrator (LSC) is disclosed. The LSC includes a transparent substrate having at least one edge surface. A dye layer is coupled to the substrate, the dye layer having a peak absorption wavelength outside the visible band, the dye layer being configured to re-emit light at a peak emission wavelength outside the visible band, at least a portion of the re-emitted light being waveguided to the edge surface of the substrate. A photovoltaic device is coupled to the edge surface of the transparent substrate, the photovoltaic device being configured to absorb light at the peak emission wavelength and generate electrical energy. ## Claims ### Claim 1 A visibly transparent photovoltaic system, comprising: a visibly transparent substrate having a top surface, a bottom surface, and a plurality of side edges, wherein the visibly transparent substrate exhibits an average visible band transmission of 45% or more; a luminescent dye layer coupled to the visibly transparent substrate, wherein the luminescent dye layer exhibits: absorption at all wavelengths in a visible band of from 0% to 50%, a peak absorption wavelength in an ultraviolet band or a near-infrared band, and a peak photoluminescent emission wavelength in the near-infrared band; a photovoltaic device positioned at a side edge of the plurality of side edges to receive photoluminescent emission from the luminescent dye layer, wherein the photovoltaic device absorbs light in the near-infrared band for generation of electrical energy; a wavelength selective mirror coupled to the top surface, wherein the wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band; and a second wavelength selective mirror coupled to the bottom surface, wherein the second wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band. ### Claim 2 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the luminescent dye layer is applied to the top surface or the bottom surface. ### Claim 3 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the luminescent dye layer is distributed throughout a thickness of the visibly transparent substrate. ### Claim 4 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the maximum absorption in the visible band of the luminescent dye layer is between 0% and 20%. ### Claim 5 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the luminescent dye layer comprises: a first dye species exhibiting a first peak absorption wavelength in the ultraviolet band or the near-infrared band and a first peak photoluminescent emission wavelength in the near-infrared band; and a second dye species exhibiting a second peak absorption wavelength in the ultraviolet band or the near-infrared band and a second peak photoluminescent emission wavelength in the near-infrared band, wherein the first peak absorption wavelength and the second peak absorption wavelength are different, and wherein the first peak photoluminescent emission wavelength and the second peak photoluminescent emission wavelength are different. ### Claim 6 (depends on 5) The visibly transparent photovoltaic system of claim 5, wherein the first peak absorption wavelength and the second peak absorption wavelength are separated from the first peak photoluminescent emission wavelength and the second peak photoluminescent emission wavelength. ### Claim 7 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the visibly transparent substrate functions as a waveguide to direct at least a portion of the photoluminescent emission generated by the luminescent dye layer to the photovoltaic device. ### Claim 8 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the wavelength selective mirror reflects light in the ultraviolet band. ### Claim 9 (depends on 1) The visibly transparent photovoltaic system of claim 1, further comprising an index matching layer between the side edge and the photovoltaic device. ### Claim 10 (depends on 1) The visibly transparent photovoltaic system of claim 1, wherein the visibly transparent substrate comprises a high refractive index material. ### Claim 11 A method of making a visibly transparent photovoltaic system, the method comprising: providing a visibly transparent substrate having a top surface, a bottom surface, and a plurality of side edges, wherein the visibly transparent substrate exhibits an average visible band transmission of 45% or more; coupling a luminescent dye layer to the visibly transparent substrate, wherein the luminescent dye layer exhibits: absorption at all wavelengths in a visible band of from 0% to 50%, a peak absorption wavelength in an ultraviolet band or a near-infrared band, and a peak photoluminescent emission wavelength in the near infrared band; coupling a photovoltaic device to a side edge of the plurality of side edges to position the photovoltaic device to receive photoluminescent emission from the luminescent dye layer, wherein the photovoltaic device absorbs light in the near-infrared band for generation of electrical energy; coupling a wavelength selective mirror to the top surface, wherein the wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band; and comprising coupling a second wavelength selective mirror to the bottom surface, wherein the second wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band. ### Claim 12 (depends on 11) The method of claim 11, wherein the luminescent dye layer comprises: a first dye species exhibiting a first peak absorption wavelength in the ultraviolet band or the near-infrared band and a first peak photoluminescent emission wavelength in the near-infrared band; and a second dye species exhibiting a second peak absorption wavelength in the ultraviolet band or the near-infrared band and a second peak photoluminescent emission wavelength in the near-infrared band, wherein the first peak absorption wavelength and the second peak absorption wavelength are different, and wherein the first peak photoluminescent emission wavelength and the second peak photoluminescent emission wavelength are different. ### Claim 13 (depends on 12) The method of claim 12, wherein the first peak absorption wavelength and the second peak absorption wavelength are separated from the first peak photoluminescent emission wavelength and the second peak photoluminescent emission wavelength. ### Claim 14 A method of generating electricity, the method comprising: providing a visibly transparent photovoltaic system, wherein the visibly transparent photovoltaic system includes: a visibly transparent substrate having a top surface, a bottom surface, and a plurality of side edges, wherein the visibly transparent substrate exhibits an average visible band transmission of 45% or more; a luminescent dye layer coupled to the visibly transparent substrate, wherein the luminescent dye layer exhibits: absorption at all wavelengths in a visible band of from 0% to 50%, a peak absorption wavelength in an ultraviolet band or a near-infrared band, and a peak photoluminescent emission wavelength in the near-infrared band; a photovoltaic device positioned at a side edge of the plurality of side edges to receive photoluminescent emission from the luminescent dye layer, wherein the photovoltaic device absorbs light in the near-infrared band for generation of electrical energy; a wavelength selective mirror coupled to the top surface, wherein the wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band; and a second wavelength selective mirror coupled to the bottom surface, wherein the second wavelength selective mirror reflects light at the peak photoluminescent emission wavelength, transmits light at the peak absorption wavelength, and transmits light in the visible band; and exposing the visibly transparent photovoltaic system to incident light having wavelengths in the visible band, wavelengths in the ultraviolet band, and wavelengths in the near-infrared band, wherein at least a portion of the incident light having wavelengths in the visible band are transmitted through the visibly transparent substrate and the luminescent dye layer, wherein the luminescent dye layer absorbs at least a portion of the incident light having wavelengths in the near-infrared band or wavelengths in the ultraviolet band, or both, and generates photoluminescent emission with the peak photoluminescent emission wavelength in the near-infrared band, and wherein at least a portion of the photoluminescent emission is absorbed by the photovoltaic device to generate electricity.