Low-power supralinear photocurrent generation via excited state fusion in single-component nanostructured organic photodetectors
Low-power supralinear photocurrent generation via excited state fusion in single-component nanostructured organic photodetectors
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DOI：
10.1039/d2tc00662f
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发表时间：
2022-04-19
影响因子：
6.4
通讯作者：
Keivanidis, Panagiotis E.
中科院分区：
文献类型：
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作者：
Antoniou, Giannis;Yuan, Peisen;Keivanidis, Panagiotis E.
将三重态-三重态湮灭（TTA）组件作为电活性元件和光学活性元件集成在垂直配置的光敏器件架构中是一项具有挑战性的任务。在这里，我们提出了一个简单的方法，将光子吸收层的（2，3，7，8，12，13，17，18-octagethy-porphyrinato）铂（ii）（PtOEP）金属有机配合物，作为自TTA湮灭介质中的类光电二极管器件结构。在低功率照明下，PtOEP光电二极管通过光诱导PtOEP激发态的融合表现出光电流产生，并且它产生高达1.15 V的开路电压（V-OC）。纳米结构PtOEP光活性层的结构和光谱表征与电子结构计算相结合，将PtOEP二聚体物质识别为负责电荷形成的湮灭激发态。的参与的融合过程中的电荷光生的机制体现在超线性的短路电流密度（J（SC））上的入射光激发强度的依赖性，无论是当非相干和相干光用于照明的PtOEP二极管。PtOEP器件的光响应允许在500-560 nm窄光谱范围内进行高度选择性和灵敏度的光检测。在短路条件下，观察到的功率定律的依赖性的装置的响应度的注量。所观察到的PtOEP光电二极管的响应揭示了迄今为止被忽视的单组分有机电子器件中的光电流生成机制，该机制由TTA反应促进。这些发现为下一代电光开关，超灵敏有机光电探测器和具有垂直配置器件结构的TTA敏化太阳能电池的制造铺平了道路。
The integration of triplet-triplet annihilation (TTA) components as electrically and optically active elements in vertically-configured photoactive device architectures is a challenging task to achieve. Herein we present a simple methodology for incorporating a photon absorbing layer of the (2,3,7,8,12,13,17,18-octaethyl-porphyrinato)platinum(ii) (PtOEP) metallorganic complex, as a self-TTA annihilator medium in a sandwich-like photodiode device structure. At low power illumination, the PtOEP photodiode exhibits photocurrent generation via the fusion of optically induced PtOEP excited states and it develops an open-circuit voltage (V-OC) as high as 1.15 V. The structural and spectroscopic characterization of the nanostructured PtOEP photoactive layer in combination with electronic structure calculations identify PtOEP dimer species as the annihilating excited state responsible for the formation of charges. The participation of the fusion process in the mechanism of charge photogeneration manifests in the supralinear dependence of the short-circuit current density (J(SC)) on the incoming photoexcitation intensity, both when incoherent and coherent light are used for illuminating the PtOEP diodes. The photoresponse of the PtOEP device allows for highly selective and sensitive photodetection within the 500-560 nm narrow spectral range. At short-circuit conditions a power-law is observed in the dependence of the device responsivity on fluence. The observed response of the PtOEP photodiodes reveals a hitherto neglected mechanism of photocurrent generation in single-component organic electronic devices that is facilitated by TTA reactions. These findings pave the way towards the fabrication of next-generation electro-optical switches, ultrasensitive organic photodetectors, and TTA-sensitized solar cells with vertically-configured device structure.