Skin-Like Near-Infrared II Photodetector with High Performance for Optical Communication, Imaging, and Proximity Sensing

Abstract

Skin-like second-near-infrared (NIR-II) photodetectors are key requirements for a flexible photodetection system that can be seamlessly integrated with three-dimensional geometries to accurately distinguish and acquire real-time various information. However, such devices exhibiting simultaneously high photosensitivity, fast photoresponse, and excellent flexibility still remain elusive. Here, we design and fabricate such skin-like NIR-II photodetectors and arrays with a simple bilayer configuration by combining a highly conducting MXene (Ti3C2T x ) and photosensitive lead sulfide quantum dots (PbS QDs), where highly promoted photocarrier separation at the interface of bilayers and efficient transport across the spatially separated layers could be achieved. Moreover, the bilayer architecture together with the strong interface bonding between the MXene and PbS QDs ensure a high-quality interface, leading to simultaneously improved optoelectronic performance and mechanical stability. Thus, the resulting device exhibits a high responsivity (1000 mA W–1), a fast photoresponse (30 ms), and excellent mechanical stability (>95% performance retention after 500 cycle bending), which renders this skin-like NIR-II photodetector highly suitable for fabricating various practical and high-performance flexible wireless photodetection systems for optical communication, NIR-II imaging, and proximity sensing in different environments. We anticipate that this simple yet high-performance skin-like MXene/PbS QDs-based photodetector would hold great potential in the applications of next-generation flexible optoelectronics.

Flexible and Stretchable Light-Emitting Diodes and Photodetectors for Human-Centric Optoelectronics

“…The PD is one of the essential components for converting light signals into electronic signals in modern optoelectronic applications, such as biomedical imaging, artificial vision systems, ,,− and optical communications. − Inspired by the photoreceptors in nature, earlier PDs were utilized in various applications (e.g., image sensors, solar cells, and photocopiers). With the rapid growth in wearable devices for healthcare, − artificial vision systems, ,− Internet of Things, ,, and augmented reality, , the demand for flexible/stretchable PDs has accelerated the development of various fabrication technologies that adopts nanomaterials, hybrids, and structural engineering (Figure ). To implement flexible/stretchable PDs, the material selection of active materials, electrodes, and substrates is particularly important to ensure sufficient flexibility and optical/electrical performance of the device.…”

Ultrathin Self-Powered Heavy-Metal-Free Cu–In–Se Quantum Dot Photodetectors for Wearable Health Monitoring

“…Photodetectors (PDs), which convert light signals into electronic signals, have been essential components in wearable electronics, − and they have been widely applied to biological imaging, optical communication, and health monitoring. − Among these, the wearable health monitoring device based on photoplethysmography (PPG), which uses a light source and a PD to measure the volumetric variations of blood circulation, has enormous potential in the measurement and diagnosis of vital signs and cardiac dysfunctions during daily lives because of noninvasiveness, cost-effectiveness, and continuous and real-time monitoring capability. − For effective real-time vital-sign monitoring, high specific detectivity ( D* ), fast response time, and excellent mechanical deformability of the PDs are essential. Therefore, realization of mechanically deformable PDs with excellent device performances and fast response time has been an overarching goal.…”

Supramolecular interface decoration on a polymer conductor for an intrinsically stretchable near-infrared photodiode

“…Near-infrared (NIR) light detection is crucial in imaging, optical communication, intelligent medical treatment and other fields. 1–7 Photodetectors based on mercury cadmium tellurium (HgCdTe) and indium gallium arsenide (InGaAs) dominate the market. 8 However, the rigid lattice structure hinders their application in wearable/implantable devices, which need to be soft, conformal with the skin, and/or stretchable.…”