The Role of Dielectric Screening in Organic Shortwave Infrared Photodiodes for Spectroscopic Image Sensing
The Role of Dielectric Screening in Organic Shortwave Infrared Photodiodes for Spectroscopic Image Sensing
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DOI：
10.1002/adfm.201805738
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发表时间：
2018-12-12
影响因子：
19
通讯作者：
Ng, Tse Nga
中科院分区：
文献类型：
--
作者：
Wu, Zhenghui;Zhai, Yichen;Ng, Tse Nga
这项工作研究了一种增加电介质屏蔽的添加剂方法，以克服有机短波红外 (SWIR) 光电二极管的性能挑战。通过瞬态光电导率和电化学阻抗的测量揭示了高介电常数添加剂樟脑酸酐在激子解离和电荷收集过程中的作用。在两种聚合物变体没有任何形态变化的情况下，介电屏蔽降低了激子结合能，从而提高了激子解离效率并降低了陷阱辅助复合损失。在最好的器件中，1100 nm 处的峰值内量子效率提高至 66%，并且光响应延伸至 1400 nm。 SWIR 光电二极管集成到 4 x 4 像素成像仪中，以展示组织分化并通过无创光谱分析估计脂肪与肌肉的比率。
This work examines an additive approach that increases dielectric screening to overcome performance challenges in organic shortwave infrared (SWIR) photodiodes. The role of the high-permittivity additive, camphoric anhydride, in the exciton dissociation and charge collection processes is revealed through measurements of transient photoconductivity and electrochemical impedance. Dielectric screening reduces the exciton binding energy to increase exciton dissociation efficiency and lowers trap-assisted recombination loss, in the absence of any morphological changes for two polymer variants. In the best devices, the peak internal quantum efficiency at 1100 nm is increased up to 66%, and the photoresponse extends to 1400 nm. The SWIR photodiodes are integrated into a 4 x 4 pixel imager to demonstrate tissue differentiation and estimate the fat-to-muscle ratio through noninvasive spectroscopic analysis.