Reciprocal Relation Between Intraband Carrier Generation and interband Recombination at the Heterointerface of Two-Step Photon Up-Conversion Solar Cells
Reciprocal Relation Between Intraband Carrier Generation and interband Recombination at the Heterointerface of Two-Step Photon Up-Conversion Solar Cells
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两步光子上转换太阳能电池异质界面带内载流子生成与带间复合之间的相互关系
DOI：
10.1103/physrevapplied.14.014010
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发表时间：
2020
影响因子：
4.6
通讯作者：
and T. Kita
中科院分区：
文献类型：
--
作者：
N. Kinugawa;S. Asahi;and T. Kita
光子上转换过程被认为对能量转换设备是有益的。最近提出的两步光子上转换(TPU)太阳能电池设计采用了具有高电子占有率的中间能级。为了理解器件物理，需要对不同的电流产生和损耗机制进行定量评估。在本工作中，我们使用了一种TPU太阳能电池，该电池包含位于An/Hetero界面前方10 nm处的An/量子点层。我们研究了光电流(PC)、辐射复合和非辐射复合与偏置电压的关系。通过积分1000到1300 nm范围内的光致发光(PL)来评估辐射带间复合。通过层的带间激发产生的光子晶体和发光信号的大小取决于偏置电压；较高的正向偏置降低了光子晶体的发光强度，增加了发光强度。我们证实，在1319 nm的红外光照射下，引起带内跃迁的PC密度增加，而光致发光强度显著降低。这种PC增强在−0.6V时表现出最大值，这反映了最大化TPU效率的最佳内部电场强度。
Photon up-conversion processes are considered beneficial for energy-conversion devices. The recently proposed two-step photon up-conversion (TPU) solar-cell design employs an intermediate level with a high electron occupation probability. To understand the device physics, a quantitative evaluation of the different current-generation and loss mechanisms is required. In the present work, we use a TPU solar cell containing an/quantum-dot layer located 10 nm in front of an/heterointerface. We study the relation between the photocurrent (PC), radiative recombination, and nonradiative recombination as a function of the bias voltage. The radiative interband recombination is evaluated by integrating the photoluminescence (PL) over the range from 1000 to 1300 nm. The magnitudes of the PC and PL signals generated via interband excitation of thelayer depend on the bias voltage; a higher forward bias reduces the PC and increases the PL intensity. We verify that, under additional infrared light illumination at 1319 nm, which induces intraband transitions, the PC density increases while the PL intensity significantly decreases. This PC enhancement exhibits a maximum at −0.6 V, which reflects the optimum internal electric field strength for maximizing the TPU efficiency.