Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology , Wuhan 430074, China.
Department of Mechanical and Materials Engineering, Nebraska Center for Materials and Nanoscience, University of Nebraska , Lincoln, Nebraska 68588-0656, United States.
ACS Appl Mater Interfaces. 2017 Mar 15;9(10):9176-9183. doi: 10.1021/acsami.6b16788. Epub 2017 Mar 1.
Low noise current is critical for achieving high-detectivity organic photodetectors. Inserting charge-blocking layers is an effective approach to suppress the reverse-biased dark current. However, in solution-processed organic photodetectors, the charge-transport material needs to be dissolved in solvents that do not dissolve the underneath light-absorbing layer, which is not always possible for all kinds of light-absorbing materials developed. Here, we introduce a universal strategy of transfer-printing a conjugated polymer, poly(3-hexylthiophene) (P3HT), as the electron-blocking layer to realize highly sensitive photodetectors. The transfer-printed P3HT layers substantially and universally reduced the reverse-biased dark current by about 3 orders of magnitude for various photodetectors with different active layers. These photodetectors can detect the light signal as weak as several picowatts per square centimeter, and the device detectivity is over 10 Jones. The results suggest that the strategy of transfer-printing P3HT films as the electron-blocking layer is universal and effective for the fabrication of sensitive organic photodetectors.
低噪声电流对于实现高灵敏度有机光电探测器至关重要。插入电荷阻挡层是抑制反向偏置暗电流的有效方法。然而，在溶液处理的有机光电探测器中，电荷输运材料需要溶解在不溶解下面光吸收层的溶剂中，但对于开发的各种光吸收材料并不总是可行的。在这里，我们介绍了一种通用的策略，即通过转印共轭聚合物聚（3-己基噻吩）（P3HT）作为电子阻挡层，实现高灵敏度光电探测器。对于具有不同活性层的各种光电探测器，转印的 P3HT 层将反向偏置暗电流大大降低了约 3 个数量级。这些光电探测器可以检测低至每平方厘米数皮瓦的光信号，器件的探测率超过 10 琼斯。结果表明，转印 P3HT 薄膜作为电子阻挡层的策略对于制备灵敏的有机光电探测器是通用且有效的。
