The ability to effectively manipulate non-equilibrium 'hot' carriers could enable novel schemes for highly efficient energy harvesting and interconversion. In the case of semiconductor materials, realization of such hot-carrier schemes is complicated by extremely fast intraband cooling (picosecond to subpicosecond time scales) due to processes such as phonon emission. Here we show that using magnetically doped colloidal semiconductor quantum dots we can achieve extremely fast rates of spin-exchange processes that allow for 'uphill' energy transfer with an energy-gain rate that greatly exceeds the intraband cooling rate. This represents a dramatic departure from the usual situation where energy-dissipation via phonon emission outpaces energy gains due to standard Auger-type energy transfer at least by a factor of three. A highly favourable energy gain/loss rate ratio realized in magnetically doped quantum dots can enable effective schemes for capturing kinetic energy of hot, unrelaxed carriers via processes such as spin-exchange-mediated carrier multiplication and upconversion, hot-carrier extraction and electron photoemission.

中文翻译：

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通过自旋交换俄歇相互作用操纵的量子点中的热电子动力学。

有效操纵非平衡“热”载流子的能力可以实现用于高效能量收集和互转换的新颖方案。在半导体材料的情况下，由于诸如声子发射之类的过程而导致的极快的带内冷却（皮秒到亚皮秒的时间尺度）使这种热载流子方案的实现变得复杂。在这里，我们表明，使用磁性掺杂的胶体半导体量子点，我们可以实现自旋交换过程的极快速率，从而实现“上坡”能量传输，并且能量增益速率大大超过了带内冷却速率。这与通常情况大不相同，在常规情况下，通过标准声子类型的能量传输，通过声子发射产生的能量耗散超过了能量增加至少三倍。