Wang Yazhong, Benduhn Johannes, Baisinger Lukasz, Lungenschmied Christoph, Leo Karl, Spoltore Donato
Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, Nöthnitzer Str. 61, 01187 Dresden, Germany.
TrinamiX GmbH-a subsidiary of BASF SE, Industriestr. 35, 67063 Ludwigshafen, Germany.
ACS Appl Mater Interfaces. 2021 May 19;13(19):23239-23246. doi: 10.1021/acsami.1c04705. Epub 2021 May 7.
Extraction barriers are usually undesired in organic semiconductor devices since they lead to reduced device performance. In this work, we intentionally introduce an extraction barrier for holes, leading to nonlinear photoresponse. The effect is utilized in near-infrared (NIR) organic photodetectors (OPDs) to perform distance measurements, as delineated in the focus-induced photoresponse technique (FIP). The extraction barrier is introduced by inserting an anodic interlayer with deeper highest occupied molecular orbital (HOMO), compared to the donor material, into a well-performing OPD. With increasing irradiance, achieved by decreasing the illumination spot area on the OPD, a higher number of holes pile up at the anode, counteracting the built-in field and increasing charge-carrier recombination in the bulk. This intended nonlinear response of the photocurrent to the irradiance allows determining the distance between the OPD and the light source. We demonstrate fully vacuum-deposited organic NIR optical distance photodetectors with a detection area up to 256 mm and detection wavelengths at 850 and 1060 nm. Such NIR OPDs have a high potential for precise, robust, low-cost, and simple optical distance measurement setups.
在有机半导体器件中，提取势垒通常是不理想的，因为它们会导致器件性能下降。在这项工作中，我们有意引入空穴提取势垒，从而产生非线性光响应。这种效应被用于近红外（NIR）有机光电探测器（OPD）中进行距离测量，如聚焦诱导光响应技术（FIP）中所描述的那样。通过将最高占据分子轨道（HOMO）比施主材料更深的阳极夹层插入性能良好的OPD中来引入提取势垒。随着辐照度的增加，通过减小OPD上的照明光斑面积来实现，更多的空穴在阳极堆积，抵消内建电场并增加体内的电荷载流子复合。这种光电流对辐照度的预期非线性响应使得能够确定OPD与光源之间的距离。我们展示了完全真空沉积的有机近红外光学距离光电探测器，其探测面积高达256平方毫米，探测波长为850纳米和1060纳米。这种近红外OPD在精确、稳健、低成本且简单的光学距离测量装置方面具有很大潜力。
