Owing to the additional usage of sub-bandgap photons, the intermediate-band solar cell has been regarded as a promising device design to exceed the conversion limits of conventional photovoltaic devices. An output-voltage preservation is theoretically possible in this kind of device in the case of independent quasi-Fermi levels. This phenomenon manifests experimentally in a voltage recovery induced by supplementary two-step photon absorption processes. Here, we study the excitation-power and temperature dependences of the voltage performance in an intermediate-band solar cell containing InAs quantum dots in Al_0.3Ga_0.7As/GaAs quantum wells. The two-color photoexcitation method is used to separately control the interband and quantum dot-conduction band transitions. The output voltage is sensitive to the balance between the two excitation densities and the cell temperature. It is found that a strongly asymmetric irradiation can even lead to a voltage decrease. The temperature-dependent data suggest a faster electron–hole annihilation at lower temperatures. We introduce a new characteristic index to qualitatively evaluate the carrier loss in the intermediate band.

中文翻译：

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InAs量子阱中点中带太阳能电池中的两步激发诱导光伏性质

由于子带隙光子的额外使用，中带太阳能电池已经被认为是有希望的器件设计，其超过了常规光伏器件的转换极限。在这种装置中，在独立的准费米能级的情况下，理论上可以保持输出电压。这种现象在实验上表现为由补充的两步光子吸收过程引起的电压恢复。在这里，我们研究在Al _0.3 Ga _0.7中包含InAs量子点的中带太阳能电池中电压性能的激发功率和温度依赖性。As / GaAs量子阱。双色光激发法用于分别控制带间和量子点导带的跃迁。输出电压对两个激励密度和电池温度之间的平衡敏感。发现强烈的不对称辐射甚至可以导致电压降低。与温度有关的数据表明，在较低温度下，电子空穴的faster灭速度更快。我们引入了一个新的特征指标，以定性评估中间频带中的载波损耗。