Siemens AG, Corporate Technology, Günter-Scharowsky-Strasse 1, 91058 Erlangen, Germany.
Sci Rep. 2013;3:1324. doi: 10.1038/srep01324.
Organic semiconductors are attractive for optical sensing applications due to the effortless processing on large active area of several cm(2), which is difficult to achieve with solid-state devices. However, compared to silicon photodiodes, sensitivity and dynamic behavior remain a major challenge with organic sensors. Here, we show that charge trapping phenomena deteriorate the bandwidth of organic photodiodes (OPDs) to a few Hz at low-light levels. We demonstrate that, despite the large OPD capacitances of ~10 nF cm(-2), a frequency response in the kHz regime can be achieved at light levels as low as 20 nW cm(-2) by appropriate interface engineering, which corresponds to a 1000-fold increase compared to state-of-the-art OPDs. Such device characteristics indicate that large active area OPDs are suitable for industrial sensing and even match medical requirements for single X-ray pulse detection in the millisecond range.
有机半导体由于能够在几平方厘米（cm2）的大面积上轻松进行处理，因此在光学传感应用中具有吸引力，而这对于固态器件来说很难实现。然而，与硅光电二极管相比，灵敏度和动态行为仍然是有机传感器的一个主要挑战。在这里，我们表明，电荷俘获现象会降低有机光电二极管（OPD）在低光水平下的带宽至几赫兹。我们证明，尽管 OPD 的电容较大，约为 10nF cm(-2)，但通过适当的界面工程，可以在低至 20nW cm(-2)的光水平下实现 kHz 级的频率响应，与最先进的 OPD 相比，这一响应提高了 1000 倍。这种器件特性表明，大面积 OPD 适用于工业传感，甚至可以满足医疗对 X 射线单脉冲检测在毫秒范围内的要求。
