title: Thermally enhanced photoluminescence for heat harvesting in photovoltaics.
abstract: The maximal Shockley-Queisser efficiency limit of 41% for single-junction photovoltaics is primarily caused by heat dissipation following energetic-photon absorption. Solar-thermophotovoltaics concepts attempt to harvest this heat loss, but the required high temperatures (T>2,000 K) hinder device realization. Conversely, we have recently demonstrated how thermally enhanced photoluminescence is an efficient optical heat-pump that operates in comparably low temperatures. Here we theoretically and experimentally demonstrate such a thermally enhanced photoluminescence based solar-energy converter. Here heat is harvested by a low bandgap photoluminescent absorber that emits thermally enhanced photoluminescence towards a higher bandgap photovoltaic cell, resulting in a maximum theoretical efficiency of 70% at a temperature of 1,140 K. We experimentally demonstrate the key feature of sub-bandgap photon thermal upconversion with an efficiency of 1.4% at only 600 K. Experiments on white light excitation of a tailored Cr:Nd:Yb glass absorber suggest that conversion efficiencies as high as 48% at 1,500 K are in reach.
authors.affiliation: Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Manor
authors.affiliation: Grand Energy Program, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Nimrod
authors.initials: N
authors.lastname: Kruger
authors.affiliation: Department of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Tamilarasan
authors.initials: T
authors.lastname: Sabapathy
authors.affiliation: Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.|Grand Energy Program, Technion-Israel Institute of Technology, Haifa 32000, Israel.|Department of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Carmel
authors.initials: C
authors.lastname: Rotschild