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Proceedings Paper

Practical considerations for solar energy thermally enhanced photo-luminescence (TEPL) (Conference Presentation)

Paper Abstract

While single-junction photovoltaics (PV's) are considered limited in conversion efficiency according to the Shockley-Queisser limit, concepts such as solar thermo-photovoltaics aim to harness lost heat and overcome this barrier. We claim the novel concept of Thermally Enhanced Photoluminescence (TEPL) as an easier route to achieve this goal. Here we present a practical TEPL device where a thermally insulated photo-luminescent (PL) absorber, acts as a mediator between a photovoltaic cell and the sun. This high temperature absorber emits blue-shifted PL at constant flux, then coupled to a high band gap PV cell. This scheme promotes PV conversion efficiencies, under ideal conditions, higher than 62% at temperatures lower than 1300K. Moreover, for a PV and absorber band-gaps of 1.45eV (GaAs PV's) and 1.1eV respectively, under practical conditions, solar concentration of 1000 suns, and moderate thermal insulation; the conversion efficiencies potentially exceed 46%. Some of these practical conditions belong to the realm of optical design; including high photon recycling (PR) and absorber external quantum efficiency (EQE). High EQE values, a product of the internal QE of the active PL materials and the extraction efficiency of each photon (determined by the absorber geometry and interfaces), have successfully been reached by experts in laser cooling technology. PR is the part of emitted low energy photons (in relation to the PV band-gap) that are reabsorbed and consequently reemitted with above band-gap energies. PV back-reflector reflectivity, also successfully achieved by those who design the cutting edge high efficiency PV cells, plays a major role here.

Paper Details

Date Published: 19 April 2017
PDF: 1 pages
Proc. SPIE 10099, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VI, 1009909 (19 April 2017); doi: 10.1117/12.2249518
Show Author Affiliations
Nimrod Kruger, Technion-Israel Institute of Technology (Israel)
Assaf Manor, Technion-Israel Institute of Technology (Israel)
Matej Kurtulik, Technion-Israel Institute of Technology (Israel)
Tamilarasan Sabapathy, Technion-Israel Institute of Technology (Israel)
Carmel Rotschild, Technion-Israel Institute of Technology (Israel)

Published in SPIE Proceedings Vol. 10099:
Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VI
Alexandre Freundlich; Laurent Lombez; Masakazu Sugiyama, Editor(s)

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