Visible blind near-infrared (NIR) photodetection is essential when it comes to weapons used by military personnel, narrow band detectors used in space navigation systems, medicine, and research studies. The technological field of filterless visible blind, NIR omnidirectional photodetection and wearability is at a preliminary stage. Here, we present a filterless and lightweight design for a visible blind and wearable NIR photodetector capable of harvesting light omnidirectionally. The filterless NIR photodetector comprises the integration of distinct features of lanthanide-doped upconversion nanoparticles (UCNPs), graphene, and micropyramidal poly(dimethylsiloxane) (PDMS) film. The lanthanide-doped UCNPs are designed such that the maximum narrow band detection of NIR is easily accomplished by the photodetector even in the presence of visible light sources. Especially, the 4fⁿ electronic configuration of lanthanide dopant ions provides for a multilevel hierarchical energy system that provides for longer lifetime of the excited states for photogenerated charge carriers to transfer to the graphene layer. The graphene layer can serve as an outstanding conduction path for photogenerated charge carrier transfer from UCNPs, and the flexible micropyramidal PDMS substrate provides an excellent platform for omnidirectional NIR light detection. Owing to these advantages, a photoresponsivity of ∼800 AW^–1 is achieved by the NIR photodetector, which is higher than the values ever reported by UCNPs-based photodetectors. In addition, the photodetector is stretchable, durable, and transparent, making it suitable for next-generation wearable optoelectronic devices.

中文翻译：

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高灵敏度，可见盲，可穿戴和全向近红外光电探测器

当涉及军事人员使用的武器，太空导航系统，医学和研究中使用的窄带检测器时，可见的近红外（NIR）光电检测必不可少。无滤光片的可见盲，近红外全向光电探测和耐磨性技术领域处于初步阶段。在这里，我们提出了一种无滤镜，轻便的设计，用于可见的可穿戴式近红外近红外光电探测器，能够全方位采集光。无滤波器NIR光电探测器包含镧系元素掺杂的上转换纳米颗粒（UCNPs），石墨烯和微金字塔形聚二甲基硅氧烷（PDMS）膜的独特功能的集成。掺杂镧系元素的UCNP的设计使得即使在可见光源存在的情况下，光探测器也可以轻松实现NIR的最大窄带检测。特别是4楼^Ñ镧系元素掺杂剂离子的电子结构提供了一种用于多级分层能量系统，该系统提供了一种用于光生电荷载流子转移到石墨烯层的激发态的寿命更长。石墨烯层可以用作从UCNPs进行光生载流子转移的出色传导路径，而柔性微金字塔PDMS基板为全向NIR光检测提供了极好的平台。由于这些优点，NIR光电探测器可实现约800 AW ^–1的光响应性，这比基于UCNPs的光电探测器曾经报道的值更高。此外，该光电探测器具有可拉伸，耐用和透明的特性，使其适用于下一代可穿戴光电设备。