State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P.R. China.
Optical Functional Theranostics Joint Laboratory of Medicine and Chemistry, The First Hospital of Jilin University, Changchun 130012 P.R. China.
Nano Lett. 2022 Mar 23;22(6):2277-2284. doi: 10.1021/acs.nanolett.1c04569. Epub 2022 Mar 8.
Near-infrared (NIR) II detection at weak flux intensity is required in medical imaging and is especially urgent in light of the low quantum efficiency of NIR-II dyes. The low responsivity of traditional photodetectors in this region limits image quality. Here, we report a NIR-II photodetector with high gain based on perovskite coupled PbS colloidal quantum dots (CQDs). Tailoring the trap density of CQDs by designing surface ligands with dual functionality contributed to control over trap-induced charge-injection upon light illumination. As a result, a detector with high gain is realized, showing external quantum efficiency of 1260% at 1200 nm and achieving the lowest detectable light intensity, that is, as low as 0.67 pW cm with a linear dynamic range of 200 dB. Devices maintain over 90% of responsivity after 150 days of storage. We acquired images of a butterfly wing, showing the skeleton texture with a maximum spatial resolution of 3.9 lp/mm.
近红外二区（NIR-II）检测需要在弱光通量下进行，这在医学成像中尤为重要，因为 NIR-II 染料的量子效率较低。该区域传统光电探测器的响应率较低，限制了图像质量。在此，我们报道了一种基于钙钛矿耦合 PbS 胶体量子点（CQDs）的高增益 NIR-II 光电探测器。通过设计具有双重功能的表面配体来调整 CQDs 的陷阱密度，有助于控制光照射下的陷阱诱导电荷注入。因此，实现了具有高增益的探测器，在 1200nm 处的外量子效率达到 1260%，并实现了最低可检测光强度，即低至 0.67pW/cm，线性动态范围为 200dB。存储 150 天后，器件的响应率仍保持在 90%以上。我们获取了蝴蝶翅膀的图像，显示了最大空间分辨率为 3.9lp/mm 的骨骼纹理。
