Jeong Hyun, Song Jung Hoon, Jeong Sohee, Chang Won Seok
Department of Nano Manufacturing Technology, Korea Institute of Machinery and Materials (KIMM), Daejeon, 34103, Republic of Korea.
Department of Energy Science (DOES), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
Sci Rep. 2020 Jul 27;10(1):12475. doi: 10.1038/s41598-020-69302-6.
A graphene-PbS quantum dot (QD) composite for application in high-performance near-infrared (NIR) photodetectors (PDs) is proposed in this study. A single-layer graphene flake and oleic acid-capped PbS QD composite is fabricated through the conventional sonication process, in hexane solution. Field emission scanning electron microscopy images of the graphene-PbS QD composite dispersed on a glass substrate confirm that the composite contains both aggregated graphene flakes and single-layer graphene with wrinkles; Transmission electron microscopy images reveal close packing with uniform size. The increased absorbance and quenched photoluminescence intensity of the graphene-PbS QD composite supports enhanced photoinduced charge transfer between graphene and the PbS QDs. Moreover, the specific Raman mode of the PbS QDs, embedded in the spectrum, is enhanced by combination with graphene, which can be interpreted by SERS as relevant to the photoinduced charge transfer between the Pbs QDs and graphene. For device application, a PD structure comprised by graphene-PbS QDs is fabricated. The photocurrent of the PD is measured using a conventional probe station with a 980-nm NIR laser diode. In the fabricated PD comprising graphene-PbS QDs, five-times higher photocurrent, 22% faster rise time, and 47% faster decay time are observed, compared to that comprising PbS QDs alone. This establishes the potential of the graphene-PbS QD composite for application in ultrathin, flexible, high-performance NIR PDs.
本研究提出了一种用于高性能近红外（NIR）光电探测器（PD）的石墨烯-硫化铅量子点（QD）复合材料。通过传统的超声处理工艺，在己烷溶液中制备了单层石墨烯薄片与油酸包覆的硫化铅量子点复合材料。分散在玻璃基板上的石墨烯-硫化铅量子点复合材料的场发射扫描电子显微镜图像证实，该复合材料既包含聚集的石墨烯薄片，也包含有褶皱的单层石墨烯；透射电子显微镜图像显示其排列紧密且尺寸均匀。石墨烯-硫化铅量子点复合材料吸光度的增加和光致发光强度的猝灭，支持了石墨烯与硫化铅量子点之间增强的光致电荷转移。此外，嵌入光谱中的硫化铅量子点的特定拉曼模式通过与石墨烯结合而增强，这可以用表面增强拉曼光谱（SERS）来解释，与硫化铅量子点和石墨烯之间的光致电荷转移有关。对于器件应用，制备了由石墨烯-硫化铅量子点组成的光电探测器结构。使用配备980 nm近红外激光二极管的传统探针台测量该光电探测器的光电流。与仅包含硫化铅量子点的光电探测器相比，在制备的包含石墨烯-硫化铅量子点的光电探测器中，观察到光电流高出五倍，上升时间快22%，衰减时间快47%。这确立了石墨烯-硫化铅量子点复合材料在超薄、柔性、高性能近红外光电探测器中的应用潜力。
