Enhanced Multiple Exciton Generation in Quasi-One-Dimensional Semiconductors
Enhanced Multiple Exciton Generation in Quasi-One-Dimensional Semiconductors
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DOI：
10.1021/nl202014a
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发表时间：
2011-08-01
期刊：
影响因子：
10.8
通讯作者：
Melinger, Joseph S.
中科院分区：
文献类型：
--
作者：
Cunningham, Paul D.;Boercker, Janice E.;Melinger, Joseph S.
单个电子-空穴对的产生（即，激子）是当前光电器件（包括光电探测器和光伏电池）的基本限制。单光子激发多激子的前景对基础科学和太阳能电池技术的发展具有重要意义。已知多激子产生发生在半导体纳米结构中，与它们的本体对应物相比具有增加的效率和降低的阈值能量。在这里，我们报告了在PbSe准一维半导体（纳米棒）中的多激子产生的显著增强超过零维纳米结构（纳米晶体），其特征在于效率增加2倍，阈值能量降低到（2.23 +/- 0.03）E-g，接近2 E（g）的理论极限。基于PbSe纳米棒的光伏电池能够提高功率转换效率，特别是当与太阳能集中器结合操作时。
The creation of a single electron-hole pair (i.e., exciton) per incident photon is a fundamental limitation for current optoelectronic devices including photodetectors and photovoltaic cells. The prospect of multiple exciton generation per incident photon is of great interest to fundamental science and the improvement of solar cell technology. Multiple exciton generation is known to occur in semiconductor nanostructures with increased efficiency and reduced threshold energy compared to their bulk counterparts. Here we report a significant enhancement of multiple exciton generation in PbSe quasi-one-dimensional semiconductors (nanorods) over zero-dimensional nanostructures (nanocrystals), characterized by a 2-fold increase in efficiency and reduction of the threshold energy to (2.23 +/- 0.03)E-g, which approaches the theoretical limit of 2E(g). Photovoltaic cells based on PbSe nanorods are capable of improved power conversion efficiencies, in particular when operated in conjunction with solar concentrators.