99/03811 Solar desalination based on humidification process II. Computer simulation: Nawayseh, N. K. et al. Energy Convers. Manage., 1999, 40, (13), 1441–1461

Abstract

This paper reviews Japanese R&D activities of III-V compound multi-junction (MJ) and concentrator solar cells. As a result of advanced technologies development for high efficiency cells and discovery of superior radiation-resistance of InGaP based materials, InGaP-based MJ solar cells have been commercialised for space use in Japan. A new world-record efficiency of 35.8% at 1 sun has been achieved with InGaP/GaAs/InGaAs 3-junction solar cell. MJ solar cells composing of multi-layers with different bandgap energies have the potential for achieving high conversion efficiencies of over 50% and are promising for space and terrestrial applications due to wide photo response. In order to solve the problems of difficulties in making high performance and stable tunnel junctions, a double hetero (DH) structure tunnel junction was found to be useful for preventing diffusion from the tunnel junction and improving the tunnel junction performance by the authors. An InGaP material instead of AlGaAs for the top cell was proposed by NREL. As a result of advanced technologies development for high efficiency cells and discovery of superior radiation-resistance of InGaP-based materials by the authors, InGaP-based MJ solar cells have been commercialised for space use even in Japan since 2002. Most recently, world-record efficiency (35.8%) at 1-sun AM1.5G has been realised with inverted epitaxial grown InGaP/GaAs/InGaAs 3-junction cells by Sharp. Since the concentrator modules have been demonstrated to produce roughly 1.7 to 2.6 times more energy per area per annum than the 14% multicrystalline silicon modules in most cities in Japan, concentrator PV (Photovoltaics) as the 3rd PV technologies in addition to the 1st crystalline Si PV and the 2nd thin-film PV technologies are expected to contribute to electricity cost reduction for widespread PV applications.