Development of Broadband PbS Quantum Dot/Graphene Photodetector Arrays with High-Speed Readout Circuits for Flexible Imagers

Abstract

Colloidal quantum dot (QD)/graphene nanohybrid heterostructures provide a promising scheme for quantum sensors as they take advantage of the strong quantum confinement in QDs with enhanced light−matter interaction, spectral tunability, suppressed phonon scattering, and extraordinary charge mobility in graphene at room temperature. Herein, we report development of a flexible, nine-channel PbS QD/graphene nanohybrid imaging array on polyethylene terephthalate using a facile process for device fabrication, signal acquisition, and processing. The PbS QD/graphene imaging array exhibited high and uniform photoresponse. At a 1.0 V bias, the highest responsivity was 9.56 × 10 3 −3.24 × 10 3 A/W for 400−1000 nm incident light [ultraviolet−visible−near-infrared (UV−vis−NIR)] with a power of 900 pW. In addition, the array has a consistent spectral response with bending down to a radius of curvature of a few millimeters. The demonstration of imaging at broadband wavelengths in the UV−vis− NIR range indicates that QD/graphene nanohybrids provide a viable approach for flexible photodetectors and imagers.

Integration of PbS Quantum Dots with 3D-Graphene for Self-powered Broadband Photodetectors in Image Sensors

“…This is because the introduction of PbS QDs increases the carrier lifetime. When PbS QDs are integrated onto the surface of 3D-graphene, under illumination and bias, the PbS QDs provide electron trap states, allowing a portion of the photogenerated carriers to be bound to the surface of the PbS QDs, thus extending the lifetime of the photogenerated carriers …”

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

“…The attempts to enhance optical and electrical properties in single material-based PDs have been expanded by hybridizing different materials, such as inorganic–organic hybrid composites ,,, and multidimensional hybrids. − For instance, organic materials exhibit mechanical flexibility, a simple and low-cost fabrication process, and tunable properties, while inorganic materials possesses high carrier mobility, stability, and a wide bandgap. The favorable optoelectronic characteristics of both materials can be achieved through inorganic–organic hybrid composites.…”

Colloidal quantum dot materials for next-generation near-infrared optoelectronics

“…In 2022, Li et al developed a wearable PPG sensor based on hetero-junctions featuring a CISe CQD thin film. 145 Expanding beyond wearable single CQD photodetectors, wearable CQD photodetectors (e.g., PbS CQD 146 ) have also been designed to cater to a broader range of applications, including multispectral which can be applied in a variety of fields (machine vision, health imaging, artificial intelligence, etc.). In 2016, Tang et al developed a flexible HgTe CQD photoconductor pixel array with different HgTe CQDs possessing different absorption features.…”

“…Expanding beyond wearable single CQD photodetectors, wearable CQD photodetectors ( e.g. , PbS CQD 146 ) have also been designed to cater to a broader range of applications, including multispectral imaging, which can be applied in a variety of fields (machine vision, health imaging, artificial intelligence, etc. ).…”