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Title: Upconversion for enhanced photovoltaics

The sun is the most abundant source of carbon-free sustainable energy, but current solar cells can only capture energy from a limited portion of the solar spectrum—specifically those photons with energies above the solar cell bandgap. Here, we explore a promising approach to reduce such transmission losses: placing an upconverter behind the solar cell. Upconverting materials can absorb low-energy photons and emit higher-energy photons back toward the solar cell, thereby improving the cell’s photocurrent. An ideal upconverter can increase the efficiency of an ideal solar cell from 30% to 44%. Existing upconverting materials offer much smaller improvements, though a boost in their upconverter efficiency could yield an absolute increase in solar cell efficiency of over 2%. We discuss several schemes to improve upconverter efficiency, focusing on the use of nanophotonic and plasmonic antennas to increase the absorption and emission of upconverters. These schemes can in theory enable orders-of-magnitude improvement in upconverter efficiency, positioning the technology for significant commercial applications.
Authors:
 [1] ;  [2] ; ; ;  [3]
  1. Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States)
  2. Department of Chemistry, Stanford University, Stanford, CA 94305 (United States)
  3. Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)
Publication Date:
OSTI Identifier:
22391277
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1652; Journal Issue: 1; Conference: 3. Conference on the Physics of Sustainable Energy: Using Energy Efficiently and Producing It Renewably, Berkeley, CA (United States), 8-9 Mar 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ANTENNAS; EMISSION SPECTRA; ENERGY EFFICIENCY; LIGHT TRANSMISSION; PHOTON EMISSION; PHOTONS; PHOTOVOLTAIC CONVERSION; PHOTOVOLTAIC EFFECT; PLASMONS; SEMICONDUCTOR MATERIALS; SOLAR CELLS; SOLAR ENERGY CONVERSION; YIELDS