Although photovoltaics made of advanced materials such as gallium arsenide can achieve nearly 30 percent efficiencies, the cost makes them suited only for use in space.

• 虽然使用如砷化镓之类先进材料制成的光电池（photovoltaics），已能达到将近30%25的效率，但其造价之昂，使得它们只适用于太空中。