Sulfurized Colloidal Quantum Dot/Tungsten Disulfide Multi‐Dimensional Heterojunction for an Efficient Self‐Powered Visible‐to‐SWIR Photodetector

Abstract

Emerging semiconducting materials show considerable promise for application in the development of next‐generation optoelectronic devices. In particular, broadband light detection is crucial in various applications, including multispectral imaging and cognition. Therefore, tuning the physical properties of semiconductors and thereby building an efficient heterojunction are important for achieving a high‐performance photodetection device. In this study, a heavy p‐type colloidal quantum dot (CQD) is synthesized through solution‐based sulfurization. The resulting cubic‐shaped CQD exhibits broadband and strong absorption, which enable its broadband absorption. Further, a multidimensional 0D‐2D heterojunction is developed using p‐type CQD and n‐type tungsten disulfide (WS2). This efficient p‐n junction is operated as a fully self‐powered optical sensor and phototransistor under various light illumination conditions. Under the self‐powered condition, the CQD/WS2 heterojunction device exhibits 440‐ and 200‐fold‐higher responsivity and detectivity, respectively, than pristine WS2.

Colloidal quantum dots and two‐dimensional material heterostructures for photodetector applications

“…Moreover, to obtain an efficient p-n junction and establish a PD with broadband detection, Kim et al 44 synthesized a heavy p-type PbS QDs (p-PbS QDs) via solution-based sulfur doping (S-doping) and then, the p-PbS QDs were deposited on the ntype multi-layer WS 2 (ML WS 2 ). The synthetic routes of p-PbS QDs were shown in Figure 8A; since S atoms were reduced susceptibility to oxidation, the synthesis process of p-PbS QDs could be more easily and accurately controlled.…”

“…Figure 2 graphically described the representative milestones of the QDs/2D material hybrid PDs over nearly 9 years. From the selection to the optimization of QDs and 2D materials, including size control, ligand exchange, doping, and bandgap engineering, PDs based on QDs/2D material heterostructures can achieve photoresponse from visible to short‐wavelength infrared region (SWIR), with microsecond‐level response speeds and superior room temperature stability 36–44 . Moreover, PDs based on QDs/2D material heterostructures with additional functions, such as brain‐like learning and health detection, have been developed to enable more diversified and multi‐scene applications 45–47 .…”

“…From the selection to the optimization of QDs and 2D materials, including size control, ligand exchange, doping, and bandgap engineering, PDs based on QDs/2D material heterostructures can achieve photoresponse from visible to shortwavelength infrared region (SWIR), with microsecond-level response speeds and superior room temperature stability. [36][37][38][39][40][41][42][43][44] Moreover, PDs based on QDs/2D material heterostructures with additional functions, such as brain-like learning and health detection, have been developed to enable more diversified and multi-scene applications. [45][46][47] These achievements based on the QDs/2D heterostructures not only demonstrate researchers' continuous exploration and innovation in the field of photodetection but also show great prospects for developing high-performance PDs in future emerging optoelectronic applications.…”

Low-Temperature Annealing of Inkjet-Printed CsPbBr3 Perovskite Nanocrystal Film for Light-Emitting Diodes

“…Metal halide perovskite materials, such as bulk film, quasi-two-dimensional (quasi-2D), nanocrystals (NCs), have garnered significant attention as promising candidates for solution-processed light-emitting diodes (LEDs) owing to their exceptional photoluminescence quantum yield (PLQY) and excellent color purity across the visible-to-near-infrared spectrum. − Inkjet printing has emerged as a promising solution process for fabricating quantum dot (QD)-based optoelectrical optoelectronic and perovskite NC-LEDs, and quasi-2D perovskite LEDs due to the small-pixel size and on-demand patterning without mask-free techniques, crucial for the display application. − This method allows for film deposition using significantly less ink compared to the spin-coating process, leading to cost reduction and an environmentally friendly process. − Inkjet-printed quasi-2D perovskite LEDs have been fabricated using metal halide precursor solutions. ,− Precursor solutions comprise metal halide and ammonium halide spacer cations dissolved in a polar solvent such as dimethyl sulfoxide (DMSO). The metal halide precursor solutions are converted to quasi-2D perovskite film during solvent evaporation after the annealing process.…”

Strain-insensitive viscoelastic perovskite film for intrinsically stretchable neuromorphic vision-adaptive transistors

“…Toward high-efficiency processing and low-power multiplexing, innovations in broadband vision-inspired neuromorphic sensors are extremely desirable 32 . However, existing stretchable photosensitive materials typically have a narrow absorption range or limited mechanical ductility that no longer pertain 20 , 24 , 33 – 35 . Although efforts have been devoted to combine perovskites with elastomer to balance stretchability and photoconversion performance 36 , achieving strain-insensitive neuromorphic vision is still in its infancy.…”