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Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion

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Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion

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Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion. Presented by Dr. Greg P. Smestad as part of the USPTO's Patent Examiner Technical Training Program, via webcast, June 29, 2017.
Purpose: To help patent examiners keep current on emerging developments in the chemical sciences, The American Chemical Society (ACS) and the U.S. Patent & Trademark Office (USPTO) sought speakers for a Technology Fair taking place on June 29, 2017. Technical areas of interest to patent examiners included solar cells and modules. Speakers gave their presentations via webcast or from any USPTO office (Washington, DC, Dallas, Denver, Detroit, or Silicon Valley). If you would like to be considered as a guest lecturer, please submit your request via the on-line form available at: www.uspto.gov/patent/initiatives/patent-examiner-technical-training-program-pettp-0

Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion. Presented by Dr. Greg P. Smestad as part of the USPTO's Patent Examiner Technical Training Program, via webcast, June 29, 2017.
Purpose: To help patent examiners keep current on emerging developments in the chemical sciences, The American Chemical Society (ACS) and the U.S. Patent & Trademark Office (USPTO) sought speakers for a Technology Fair taking place on June 29, 2017. Technical areas of interest to patent examiners included solar cells and modules. Speakers gave their presentations via webcast or from any USPTO office (Washington, DC, Dallas, Denver, Detroit, or Silicon Valley). If you would like to be considered as a guest lecturer, please submit your request via the on-line form available at: www.uspto.gov/patent/initiatives/patent-examiner-technical-training-program-pettp-0

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Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion

  1. 1. Title: Chemistry, materials science and technology related to photovoltaic, and photoelectrochemical solar energy conversion Presented to the USPTO June 29, 2017 Dr. Greg P. Smestad Title: Chemistry, materials science and technology related to quantum solar energy conversion
  2. 2. Structure of the Talk •  Overview of PV components •  Silicon Technologies •  Thin Film PV •  Concentrator Approaches •  Next GeneraNon PossibiliNes •  Future Issues
  3. 3. Approach •  SimilariNes and Differences •  Recent developments and future trends in R&D and innovaNon. •  LocaNons & Sources to find out more. (e.g., search engines listed here: hWp://www.solideas.com/links.html#Journals) •  Thermodynamic Limits (ge[ng above the details) > Detailed Balance. •  CollaboraNve, InternaNonal
  4. 4. Pace and Flow of the Talk •  Some slides are background and will be covered within 15 sec. •  Other sides are rich in content and will be covered for a minute or more. •  You will have the chance to ask quesNons at the end. •  The slides will be made available to you.
  5. 5. Solar Energy Emerging as Cheapest Power Source in Many Parts of the World •  By 2025, solar power in sunny regions of the world will be cheaper than power from coal or gas. Success depends on stable regulatory condiNons •  By 2025, the cost of producing power in central and southern Europe will have declined to (LCOE) between 4 and 6 cents per kilowaW hour, •  and by 2050 to as low as 2 to 4 cents •  Study by the Fraunhofer InsNtute for Solar Energy Systems commissioned by Agora Energiewende. •  Solar power is already cost-effecNve: •  In the sunny, desert country of Dubai, a long-term power purchase contract was signed recently for 5 cents per kilowaW hour, •  In Germany, large solar plants deliver power for less than 9 cents. •  Electricity from new coal and gas-fired plants costs between 5 and 10 cents per kilowaW hour •  and from nuclear plants as much as 11 cents. hWp://www.agora-energiewende.org
  6. 6. Sources Optoelectronics of Solar Cells SPIE Monograph PM115, by Greg P. Smestad ISBN 0-8194-4440-5 118 pages; Pub. July 2002; Sogcover; www.solideas.com/SolarCellBook.html Published secNons in journals are here: hWp://www.solideas.com/bio/pubs.html
  7. 7. Solar Cell (N and P layers) Chapter 16 bandgap. This bandgap is 1.1 eV for Si and corresponds to a threshold wavelength of 1100 nm. If light of wavelengths shorter than 1100 nm enters a thick Si wafer, it is absorbed. This produces an electron in the CB, while leaving holes in the VB. Fig. 1.1 A solar cell showing the processes of reflection of the incident light photons, ligh absorption by the semiconductor, free carrier generation via the absorption of light, and charge transport to the contacts. Electricity is produced in an external load (in this case a Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  8. 8. Energy Band Diagram: Balance Chapter 18 Fig. 1.4 Photoluminescent emission and nonradiative recombination compete with current Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  9. 9. Energy Band Diagram: Pump Solar Cell Equations 49 Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  10. 10. I(V) = ISC − I0 exp qV γ kT # $% & '( − 1 ) * + , - . Courtesy: Alexis de Vos With Technology Advancements, What Parameters Will Change for PV modules? •  Open Circuit Voltage (VOC) will increase. •  Fill Factor (FF) will increase. •  Series resistance reducNons. •  Slow, but conNnued improvements in current density (mA/cm2)
  11. 11. Cell to PV Module Light, Glass, Surfaces, Contacts, Semiconductor(s), Losses, Back Metal Contact. or the ìidealityî factor. For a perfect diode, g is unity, but its value ranges from 1 o 2 in typical devices. The multiplier I0 is called the ìsaturation currentî and is Fig. 3.1 Side view schematic of a solar cell showing the various layers, the process of harge separation charge transport and, finally, charge collection by the external contacts.Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  12. 12. PV Module: More Materials ntroduction to Solar Cells 1 ig.1.5 A PV module using individual solar cells. For example, the two solar cells shown an be individually (series) connected silicon cells. anel, a tempered glass sheet is combined with a sheet of an encapsulant lik ilicone or ethylene-vinyl acetate (EVA) and laid into an assembly machin A PV module using individual solar cells. For example, the two solar cells shown can be individually (series) connected silicon cells. Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  13. 13. Courtesy of Al Hicks (NREL)
  14. 14. InternaNonal Technology Roadmap for Photovoltaics (ITRPV) Applied Materials Innolas Silicor Materials ASM Alternative Energy ISFH Singulus Technologies BE Semiconductor Industries Meyer Burger Sodetal AWT s.a.s Bernreuter Research Motech Industries* SolarWorld Centrotherm photovoltaics AG Neo Solar Power* Sol Voltaics ECN Solar Energy Pillar Ltd. Teamtechnik Fraunhofer ISE PV Crystalox Technology K Gerlach New Energy Consulting REC Silicon* University of New South Wales h.a.l.m. elektronik* RENA VDMA Hanwha Q-Cells* Robert Bürkle Vitronic Helios Resource Samsung SDI Von Ardenne Heraeus Photovoltaics SAS Wafer* Wacker Chemie AG IMEC SiCon InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net
  15. 15. InternaNonal Technology Roadmap for Photovoltaics (ITRPV) 8th ediNon:
  16. 16. Trends in Si Cells & Modules •  Thinner wafers •  Low cost stacks for metallizaNon – Lower Ag per waW of PV •  AR coaNngs •  Texturizing surfaces •  PassivaNon for reduced recombinaNon •  Polymer materials for encapsulant & back sheet
  17. 17. Trends: Novel TexturizaNon 28 Chapter 2 Fig. 2.10 Geometry for calculation of the absorptivity from a polished (left side) and textured (right side) light absorber. In each case, a summation of multiple reflections must be made in order to calculate the absorptivity. The angle q is measured from the surface normal. Geometry for calculaNon of the absorpNvity from a polished (leg side) and textured (right side) light absorber. In each case, a summaNon of mulNple reflecNons must be made in order to calculate the absorpNvity. The angle is measured from the surface normal.
  18. 18. ModificaNons to cell architecture are needed for higher efficiencies “Standard cell” Al-BSF “PERC cell” Passivated rear contact •  Rear Al-Si contact and reflector •  PVD Al/Al paste •  Rear dielectric layers: SiOx; AlOx; SiNy:H
  19. 19. Present From Al-BSF to PERC n  Replacement of the full area Al- BSF with a par=al rear contact (PRC) n  Two addiNonal process steps n  Dielectric passivaNon n  Local contact opening (LCO) or Laser fired contact (LFC) SDE/Texture POCl diffusion Edge IsolaNon PSG etching SiN ARC SP Ag FS Drying & Firing SP Al/Ag RS Al2O3/ SiN RS Laser Opening
  20. 20. Technology Group 1 (PERC and SelecNve EmiWer) Cells (20 – 22% efficiency) Courtesy of Al Hicks (NREL)
  21. 21. n-type versus p-type Si •  Pro n-type –  No light-induced degradaNon (no B-O complexes) –  More forgiving towards metallic impuriNes (Fe) –  Longer diffusion lengths •  Contra n-type –  B-diffusion requires high temperature –  EmiWer passivaNon •  High-efficiency concepts are ogen based on n-type Si (Sunpower, Sanyo, Yingli Solar) www.ecn.nl Courtesy of “Quo Vadis, Crystalline Silicon PV?” IMEC, Belgium, Dr. Ivan Gordon
  22. 22. Fig. 10: Trend for remaining silver per cell (156x156mm²). InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net Trend for remaining silver per cell (156x156mm²) ITRPV2017 0 20 40 60 80 100 120 2016 2017 2019 2021 2024 2027 Amountofsilverpercell[mg/cell]
  23. 23. Advantages of Ni/Cu plated contacts over Ag screen-printed contacts •  Potential for cost reduction, better efficiencies and more advanced cell structures (e.g., PERC) Ag Screen print Ni/Cu/Sn Advantage Lower base material cost High Much Lower Cost reduction potential Lower contact resistance High 10 x Lower Permits narrow contacts + Ns↓ homogeneous emitters Better conductivity Higher Lower Allows narrower lines, Lower Rs losses Narrower line widths >50µm <50µm Less Shading Lower firing temperature 750-850ºC 250-400ºC Passivation options ↑ Rear reflectance↑ Courtesy of “Quo Vadis, Crystalline Silicon PV?” IMEC, Belgium, Dr. Ivan Gordon
  24. 24. Technology Group 2: Interdigitated Back Contact Cells (≈25% efficiency) Courtesy of Al Hicks (NREL)
  25. 25. SunPower panel, Greg Smestad, Willow Glen, San José, CA
  26. 26. Technology Group 3: Heterojunction Intrinsic Thin Layer, or HIT, Cells (≈24% efficiency) Courtesy of Al Hicks (NREL)
  27. 27. Think Thin Courtesy of “Quo Vadis, Crystalline Silicon PV?” IMEC, Belgium, Dr. Ivan Gordon
  28. 28. Wafer Thickness InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net 140 µm. It is assumed that the thickness of mc-Si wafers will slowly approach a minimum value of 150 µm until 2027. Mono-Si wafer thickness will follow a faster thickness reduction down to 140 µm in 2027. Fig. 9: Predicted trend for minimum as-cut wafer thickness and cell thickness for mass production of c-Si solar cells and modules. Metallization pastes/inks containing silver (Ag) and aluminum (Al) are the most process-critical and most expensive non-silicon materials used in current c-Si cell technologies. Paste consumption there- fore needs to be reduced. Fig. 10 shows our estimations regarding the future reduction of the silver Trend for minimum as-cut wafer thickness and cell thickness 90 100 110 120 130 140 150 160 170 180 190 2016 2017 2019 2021 2024 2027 [µm] Wafer thickness multi Wafer thickness mono limit of cell thickness in future modul technology ITRPV2017
  29. 29. Future What is the Limit of Silicon Solar Cells n  Shockley, Queisser (1961) Limit for Si 33% (AM1.5) n  LimitaNons by thermalizaNon and transmission n  Auger Limit 29.4 %1 400 600 800 1000 1200 1400 1600 1800 2000 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 Transmission loss Bandgap Usable power Thermalization loss Intensity[Wm -2 nm -1 ] Wavelength [nm] 1Richter, Hermle, Glunz, IEEE J. Photovolt. (2013)
  30. 30. Future What is the Limit of Silicon Solar Cells n  Shockley, Queisser (1961) Limit for Si 33% (AM1.5) n  LimitaNons by thermalizaNon and transmission n  Auger Limit 29.4 %1 1Richter, Hermle, Glunz, IEEE J. Photovolt. (2013) à End of Silicon Solar Cell Technologies? 2010 2015 2020 2025 2030 18 20 22 24 26 28 30 Averagecellconversionefficiency[%] ~ 29 % Passiva=ng Contacts ~ 25.0 % PERC ~ 20 % PERC ~ 23.5 % ~ 26.0 % Passiva=ng Contacts BJBC Al-BSF
  31. 31. Some future Trends for crystalline Si PV CELL DEVELOPMENT –  New device structures for p-type industrial solar cells to obtain >20% efficiencies –  TransiNon from p-type to n-type Si substrates –  Reduced material costs / improved sustainability –  Thinner Si substrates –  Different cell architectures for different applicaNons –  Bifacial –  BIPV Courtesy of “Quo Vadis, Crystalline Silicon PV?” IMEC Belgium, Dr. Ivan Gordon
  32. 32. Courtesy of Al Hicks (NREL)
  33. 33. Different front cover materials World market share [%] ITRPV2017 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 2016 2017 2019 2021 2024 2027 non-structured & non-coated front glass AR-coated front glass deeply structured front glass Fig. 11: Expected relaNve market share of different front cover materials. InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net
  34. 34. Different encapsulation materials World market share [%] ITRPV2017 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 2016 2017 2019 2021 2024 2027 EVA (Ethylene Vinyl Acetat) Polyolefin PDMS (Polydimethyl Silicone) / Silicone PVB (Polyvinyl Butyral) TPU (Thermoplastic Polyurethan) Fig. 16: Expected market shares for different encapsulaNon materials. InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net
  35. 35. Different backsheet materials and technologies World market share [%] ITRPV2017 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 2016 2017 2019 2021 2024 2027 TPT (Tedlar-Polyester-Tedlar) TPA (Tedlar-PET-Polyamid) APA (Polyamid-PET-Polyamid) Polyolefien (PO) KPE (Kynar (PVDF)- PET- EVA) Glas other Fig. 17: Back cover technologies. InternaNonal Technology Roadmap for Photovoltaics (ITRPV). More informaNon is available at www.itrpv.net
  36. 36. Thin Film PV Courtesy of Al Hicks (NREL)
  37. 37. Thin Film PV Chapter 112 Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  38. 38. CdTe Monolithically Interconnected Courtesy of Al Hicks (NREL)
  39. 39. Thin Film vs Wafer PV Courtesy of Al Hicks (NREL)
  40. 40. SimilariNes common of which is crystalline Si. All solar cells share similarities at the fundamental level. One side of the device is conductive for electrons, and the opposite side of the device is conductive toward holes. Table 1.1 shows some of the various types of materials used in solar cells. Table 1.1 Examples of some of the types of PV Cells. The hole conductor (hole cond.) in a DSSC is a material such as CuI, CuSCN, redox couple, or even a polymer, capable of conducting holes. This tutorial focuses on the c-Si device as an example. PV Cell N-type layer P-type layer Crystalline Silicon, c-Si c-Si doped c-Si doped Gallium Arsenide, GaAs GaAs GaAs and AlGaAs Amorphous Silicon, a-Si a-Si doped a-Si doped Multicrystalline Si, Poly-Si Poly-Si Poly-Si Cadmium Telluride, CdTe CdS or ZnO CdTe Copper indium diselenide (-sulfide), CuInSe2, (CuInS2) CdS or ZnO CuInSe2 or CuInS2 Organic and polymer blend solar cells Organic Molecule Organic Molecule Dye Sensitized Solar Cell, DSSC TiO2 + Dye I- /I3 - , or hole cond. One type of solar cell not listed above is the Schottky barrier device, in which only a P-type or N-type layer is used along with a metal or highly doped transparent conductive oxide (TCO). In this case, the band diagram looks like Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  41. 41. CdTe Courtesy of Al Hicks (NREL) Issues: •  CdTe back contact •  Back contact buffer •  Thermal stability •  Recycling/ Availability Promise: •  Lowest LCOE of PV •  High volume producNon •  Experience
  42. 42. CdTe Courtesy of Al Hicks (NREL) •  Champion CdTe solar conversion efficiency is now about 22.1%, •  and the PV module efficiency is 16.4%. •  The JSC is close to its theoreNcal maximum. •  Large potenNal for improvement of VOC and FF. •  PotenNal for decreasing the CdTe thickness. Alan L. Fahrenbruch
  43. 43. CIGS •  Polycrystalline Thin Film Photovoltaic Solar Cell Based on the Copper Indium Gallium Diselenide (CIGS) Material System •  Typical Structure –  Molybdenum/CIGS/ Cadmium Sulfide/Indium Tin Oxide •  Formed on Substrates –  Glass –  Stainless Steel –  Polymer •  Good low-light-level performance •  CIGS-based tandem solar cells •  Flexible and lightweight CIGS modules 1.257 m  0.977 m, and 1.65 m  0.65 m sizes just for glass– designs) and substrate type, as mentioned. Additionally, a native device designs may be employed. For example, althoug sputtered i-ZnO/AZO front contact is common in CIGS m facturing and the literature, the majority of commercial Fig. 1. Schematic of a monolithic CIGS device. For our reference case, we ass framed, glass–glass module with a 1.5-micron-thick CIGS layer.Courtesy of Al Hicks (NREL)
  44. 44. CIGS designs) and substrate type, as mentioned. Additionally, a native device designs may be employed. For example, althoug sputtered i-ZnO/AZO front contact is common in CIGS m facturing and the literature, the majority of commercial Fig. 1. Schematic of a monolithic CIGS device. For our reference case, we ass framed, glass–glass module with a 1.5-micron-thick CIGS layer.Courtesy of Al Hicks (NREL) Issues: •  Moisture sensiNvity of AZO/ZnO •  Ternary system •  Alkali (Na) post- deposiNon treatment •  ComposiNon grading in CIGS •  Surface passivaNon •  Buffer layers •  Recycling/Availability (Ga)
  45. 45. BeWer Together CitaNon: Semi-transparent Perovskite Solar Cells for Tandems with Silicon and CIGS, Colin D. Bailie, Michael Grätzel, Rommel, Noufi et. al, Energy Environ. Sci., 2015, 8, 956-963. DOI: 10.1039/C4EE03322A
  46. 46. Earth Abundance CZTS(e) Figure 3 - EBIC image of CZTSSe device. Sintered CZTS NanoparNcle Solar Cells on Metal Foil, Subcontract Report NREL/SR-5200-56501, September 2012 Contract No. DE- AC36-08GO28308. Compound semiconductor Cu2ZnSn(S, Se)4 [CZT(S, Se)] is a cousin to Cu(In, Ga)Se2 (CIGS)
  47. 47. Courtesy of Al Hicks (NREL) Recycling and ReclamaNon
  48. 48. Courtesy of Al Hicks (NREL)
  49. 49. What about PV Technologies that concentrate the sunlight?
  50. 50. A concentrator transfers light from one area to another Graphic: Al Hicks/NREL based on: R. Winston, J.C. Miñano, and P. Benítez, Nonimaging OpNcs (Elsevier, 2005). EquaNon Exit aperture Entrance aperture
  51. 51. For a Linear System (2D Concentrator) n is the index of refracNon. Concentrator equaNon
  52. 52. Figure Adapted From: Renewable Energy — Sources for Fuel and Electricity, Thomas B. Johansson, Henry Kelly, Amulya K.N. Reddy, and Robert H. Williams, Island Press, 1993. 2D trough concentrator - Parabola dragged along a line Courtesy of Al Hicks (NREL)
  53. 53. LCPV system: SunPower C7 (Ar=st Rendering) Courtesy of Al Hicks (NREL)
  54. 54. CURRENT STATUS OF CONCENTRATOR PHOTOVOLTAIC (CPV) TECHNOLOGY FRAUNHOFER INSTITUTE FOR SOLAR ENERGY SYSTEMS ISE NATIONAL RENEWABLE ENERGY LABORATORY NREL
  55. 55. A RepresentaNve Module for III-V Cells (the Fresnel Lens Box) Courtesy of Al Hicks (NREL)
  56. 56. Energy band-gap versus la[ce constant for several semiconductors used in MJ HCPV cells. Source: Eduardo F. Fernández, Antonio J. García-Loureiro, Greg P. Smestad, MulNjuncNon Concentrator Solar Cells: Analysis and Fundamentals, Ch. 2 in P. Pérez-Higueras, E.F. Fernández (Eds.) High Concentrator Photovoltaics Fundamentals, Engineering and Power Plants
  57. 57. Source: Eduardo F. Fernández, Antonio J. García-Loureiro, Greg P. Smestad, MulNjuncNon Concentrator Solar Cells: Analysis and Fundamentals, Ch. 2 in P. Pérez-Higueras, E.F. Fernández (Eds.) High Concentrator Photovoltaics Fundamentals, Engineering and Power Plants
  58. 58. Single junction vs. Multijunction solar cell ü  Single junction (silicon conventional PV)→ “one size fits all” ü  Multijunctions → better exploitation of the solar spectrum and higher efficiency The efficiency limit for an ideal Si solar cell is η=29% The efficiency limit for an ideal MJ solar cell is η=86% Thermalisation Non absorbed light Output power Non absorbed light Thermalisation Output power Prof. Ignacio Rey-Stolle
  59. 59. What can be expected?: •  Improved coaNngs. •  Advances in contacts. •  III-V alloy subsNtuNons and process improvements. •  InnovaNons for use as PV modules used for aerospace applicaNons (its main market). •  Re-usable substrates •  Tandem concepts. Courtesy of Al Hicks (NREL)
  60. 60. Courtesy of Al Hicks (NREL)
  61. 61. Single-Junction III-Vs Proof-of-Concept Within the Published Literature: 2” diameter single-junction GaAs on a flexible carrier (right). The solar cell was grown from (100) GaAs wafers with a misorientaNon of 2° towards [110] (leg figure). From J J Schermer, G J Bauhuis, P Mulder, E J Haverkamp, J van Deelen, A T J van Nigrik, P K Larsen ‘Photon confinement in high-efficiency, thin-fill III-V solar cells obtained by epitaxial lig-off’. Thin Solid Films 511-512 (2006) 645-653.
  62. 62. III-Vs on Cz-Si NREL Model Device Diagram 9/13/2013 Device concept inspired by “Epitaxially-Grown Metamorphic GaAsP/Si Dual-Junction Solar Cells” from T J Grassman, J A Carlin, C Ratcliff, D J Chmielewski, and S A Ringel Proceedings of the IEEE PVSC (2013).
  63. 63. §  The space market for III-V MJSCs o  Providing satellite power is how PV began o  Power to weight ratio (Wp/kg) is the key o  Power cost (at cell level) is ~150$/Wp o  Large area (~20 to ~70 cm2) o  Designed for end-of-life (i.e. degradation is key) ü  Large thermal variations ü  Particle radiation hardness o  State of the art efficiencies are ~30% (AM0) o  ~250.000 cells/yr (Europe) o  115 satellites per year in 2014-2024 Space power is a captive market for III-V multijunction solar cells, which allows to further develop the learning curve of these devices III-V Solar Cells: Architectures and Fields of Application Prof. Ignacio Rey-Stolle
  64. 64. Xing Ju, Chao Xu, Yangqing Hu, Xue Han, Gaosheng Wei, Xiaoze Du, A review on the development of photovoltaic/ concentrated solar power (PV-CSP) hybrid systems, Solar Energy Materials and Solar Cells, Volume 161, March 2017, Pages 305-327. H.M. Branz, W. Regan, K.J. Gerst, J.B. Borak, E.A. Santori Hybrid solar converters for maximum exergy and inexpensive dispatchable electricity Energy Environ. Sci. (2015).
  65. 65. New Approaches?
  66. 66. In 1839, at age 19, experimenNng in his father's laboratory, Alexandre-Edmond Becquerel created the world's first photovoltaic cell. In this experiment, silver chloride was placed in an acidic soluNon and illuminated while connected to plaNnum electrodes, generaNng voltage and current. Because of this work, the photovoltaic effect has also been known as the "Becquerel effect". E. Becquerel (1839). "Mémoire sur les effets électriques produits sous l'influence des rayons solaires". Comptes Rendus. 9: 561–567. hWp://gallica.bnf.fr/ark:/12148/bpt6k2968p/f561.chemindefer
  67. 67. ChrisNana Honsberg and Stuart Bowden hWp://www.pveducaNon.org/pvcdrom/manufacturing/first-photovoltaic-devices Accessed on June 22, 2017, Nihil sub sole novum
  68. 68. 4.2 Operation of the dye-sensitized nanocrystalline TiO2 solar cell. Light is absorbed he dye molecule (sensitizer) and the resulting excited electron is “injected” into the . The electrons then diffuse within the porous TiO2 structure and are collected at the k contact (conductive transparent glass). The resulting positive charge on the dye is pensated by the mediator, which itself is reduced after the electron has passed OperaNon of typical nanopar=cle solar cell. Light is absorbed, for example by a dye, and the electron is “injected” into the acceptor such as TiO2. The resulNng posiNve charge needs a “hole” conductor to complete the circuit. Optoelectronics of Solar Cells, SPIE Monograph PM115, by Greg P. Smestad
  69. 69. NanoparNcle zoo MulNple exciton generaNon for photoelectrochemical hydrogen evoluNon reacNons with quantum yields exceeding 100%, Yong Yan, Ryan W. Crisp, Jing Gu, Boris D. Chernomordik, Gregory F. Pach, Ashley R. Marshall, John A. Turner & MaWhew C. Beard, Nature Energy 2, ArNcle number: 17052 (2017). Courtesy of Al Hicks (NREL)
  70. 70. Courtesy of Al Hicks (NREL)
  71. 71. Polymer and organic molecule-based solar cells that can be printed on various flexible substrates. Courtesy of Al Hicks (NREL)
  72. 72. Si nanowire PV Courtesy of Al Hicks (NREL)
  73. 73. Perovskite Solar Cells •  The stability and efficiency •  CH3NH3PbI3 structure
  74. 74. Bonding Crystal structure Courtesy of Al Hicks (NREL)
  75. 75. Courtesy of Al Hicks (NREL)
  76. 76. Courtesy of Al Hicks (NREL)
  77. 77. Metal-halide perovskite solar cells Crystal structure of CH3NH3PbX3 perovskites (X=I, Br and/or Cl). The methylammonium caNon (CH3NH3 +) is surrounded by PbX6 octahedra. Now: •  Cu (I/II) complexes •  redox shuWles in liquid electrolytes •  solid hole conductors •  Power conversion efficiency (PCE) > 22%. •  Open-circuit voltages > 1.24 V (excepNonal for a material with a bandgap of 1.6 eV).
  78. 78. Fuels & Chemicals from Solar+Biology Courtesy of Al Hicks (NREL)
  79. 79. Future Intellectual Property: The method to find new materials for solar •  High-throughput combinatorial methods •  Materials by Design and Materials Genome Courtesy of Al Hicks (NREL)
  80. 80. PrinNng Inks of varying composiNon Courtesy of Al Hicks (NREL)
  81. 81. ComputaNonal Science + Materials Stock NREL 25944-FP.jpg
  82. 82. Conclusions •  Solar Cells consist of a region of electron conducNon separated by a barrier from a hole conducNon region. •  Certain materials and configuraNons have favorable properNes for large-scale commercial development of PV. •  Techniques are emerging to predict, screen and characterize large numbers of potenNally viable chemistries and materials.
  83. 83. Acknowledgements Alfred Hicks Graphics ArNst, Illustrator Specialist NaNonal Renewable Energy Laboratory, NREL Tel. 303-384-6410 Dr. Ivan Gordon imec I Belgium Manager Silicon Photovoltaics Group Ivan.Gordon@imec.be I www.imec.be Dr. MarNn Hermle Head of "High-Efficiency Silicon Solar Cells” Dept. Fraunhofer-InsNtut für Solare Energiesysteme ISE JuWa Trube, Managing Director VDMA Photovoltaic Equipment Int’l Technology Roadmap for Photovoltaics (ITRPV) 8th ed. PV Manufacturing in Europe Conference Brussels, May 19th 2017
  84. 84. Acknowledgements Prof. Ignacio Rey-Stolle Solar Energy InsNtute Technical University of Madrid * Madrid, Spain
  85. 85. Greg P. Smestad, Sol Ideas Technology Development San José, California, USA smestad@solideas.com — hDp://www.solideas.com/ Greg P. Smestad, Ph.D. was the Associate Editor of the journal Solar Energy Materials and Solar Cells from 1990-2016. He is the author of Optoelectronics of Solar Cells (SPIE Press), and the sole proprietor of Sol Ideas Technology Development. To contact today’s speaker:

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