The highest solar cell efficiencies today are reached with four-junction devices under concentrated illumination. The optimal bandgap combination for realistic four-junction cells is modelled to be 1.89/1.42/1.05/0.68 eV and indeed promises for efficiencies >50%. We present the development and analysis of a wafer-bonded four-junction solar cell based on GaInP/GaAs/GaInAs//GaInAsSb. This concept allows for the implementation of these ideal bandgaps and exhibits at present an efficiency of 42.0±2.5% at a concentration of 599x AM1.5d. The present loss mechanisms in this device are analyzed, which are dominated by current losses due to mismatched subcell currents and absorbing passive layers. Under the assumption of proper current matching, this device would achieve an efficiency above 44%.

中文翻译：

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聚光效率42%锑化物硅片键合四结太阳能电池的开发与分析

当今最高的太阳能电池效率是在集中照明下使用四结器件实现的。实际四结电池的最佳带隙组合被建模为 1.89/1.42/1.05/0.68 eV，并且确实有望实现 >50% 的效率。我们介绍了基于 GaInP/GaAs/GaInAs//GaInAsSb 的晶片键合四结太阳能电池的开发和分析。这个概念允许实现这些理想的带隙，目前在 599x AM1.5d 的浓度下表现出 42.0±2.5% 的效率。分析了该器件中目前的损耗机制，主要是由于不匹配的子电池电流和吸收无源层造成的电流损耗。在适当电流匹配的假设下，该设备将实现 44% 以上的效率。