Polaron Photoconductivity in the Weak and Strong Light-Matter Coupling Regime
Polaron Photoconductivity in the Weak and Strong Light-Matter Coupling Regime
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DOI：
10.1103/physrevlett.124.177401
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发表时间：
2020-04-30
影响因子：
8.6
通讯作者：
Giebink, Noel C.
中科院分区：
文献类型：
--
作者：
Krainova, Nina;Grede, Alex J.;Giebink, Noel C.
我们研究了通过激发带电分子（极化子）产生的光电流，在掺杂有机半导体中进行腔修饰电子转移的潜力。当极化子光学跃迁与Fabry-Perot微腔模式强耦合时，我们在光导作用谱中观察到极化子的极化子，发现它们的大小取决于外加电场，而不是由同一腔中非耦合极化子激发产生的光电流。至关重要的是，从正失谐到负失谐会导致上下极化子光电流交换它们的场依赖关系，更像极化子的分支类似于不耦合激励的分支。这些观察结果是基于一个现象学模型来理解的，在这个模型中，强耦合通过有效地增加光激发电荷载流子的热化长度来改变极化子与其掺杂反离子的Onsager解离。
We investigate the potential for cavity-modified electron transfer in a doped organic semiconductor through the photocurrent that arises from exciting charged molecules (polarons). When the polaron optical transition is strongly coupled to a Fabry-Perot microcavity mode, we observe polaron polaritons in the photoconductivity action spectrum and find that their magnitude depends differently on applied electric field than photocurrent originating from the excitation of uncoupled polarons in the same cavity. Crucially, moving from positive to negative detuning causes the upper and lower polariton photocurrents to swap their field dependence, with the more polaronlike branch resembling that of an uncoupled excitation. These observations are understood on the basis of a phenomenological model in which strong coupling alters the Onsager dissociation of polarons from their dopant counterions by effectively increasing the thermalization length of the photoexcited charge carrier.