《Luminescent layers for enhanced silicon solar cell performance Down-conversion》.pdf

ARTICLE IN PRESS Solar Energy Materials Solar Cells 90 (2006) 1189–1207 /locate/solmat Luminescent layers for enhanced silicon solar cell performance: Down-conversion B.S. Richards1 Centre of Excellence for Advanced Silicon Photovoltaics and Photonics, University of New South Wales, Sydney, New South Wales 2052, Australia Received 8 July 2004; received in revised form 2 December 2004; accepted 1 July 2005 Available online 29 August 2005 Abstract A down-converting (DC) layer placed on the front side of a silicon solar cell has the potential to generate more than one low-energy photon for every incident high-energy photon. Recent theory has predicted that DC in conjunction with a silicon solar cell can achieve a conversion efficiency of up to 38.6%. This paper examines the application of rare-earth-doped inorganic materials for achieving external quantum efficiencies greater than unity and enhancing the conversion efficiency of silicon solar cells. Such DC mechanisms have been applied in similar phosphor materials used by the lighting and display industries. The opportunities for the DC of high-energy solar photons to multiple photons with energy greater than the silicon bandgap are discussed. r 2005 Elsevier B.V. All rights reserved. Keywords: Luminescence; Down-conversion; Quantum cutting; Rare-earths; Solar cells; Photovoltaics Abbreviations: CB, conduction band; CRT, cathode ray tube; DC, down-conversion; EQE, external quantum efficiency; II, impact ionisation; IQE, internal quantum efficiency; IR, infrared; MP, multiphonon; NIR, near infrared; PDP, plasma display panel; PV, photovolta