Flexible Self‐Powered Electrochemical Photodetector Functionalized by Multilayered Tantalum Diselenide Nanocrystals

Abstract

electrical and optical characteristics, a large specific surface area, and great mechanical strength garnering a lot of interest in the field of high-performance and flexible optoelectronic devices. [3][4][5] 2D materials cover the spectrum from ultraviolet to terahertz (THz) waves and therefore most preferred materials for visible and THz optoelectronics. [6] Chemical doping and band engineering can alter the mid-infrared absorption of 2D materials. [7] 2D materials based photodetectors have been reported to exhibit suitable performance in the framework of plasma self-mixing and thermoelectric effect. [8,9] Graphene is a popular 2D material in broadband photo detectors because of its high carrier mobility. Limitations including lack of bandgap and weak optical absorption which restrict the production of photoexcited charge carries lead to low photoresponsity of ≈10 −1 A W −1 . [10][11][12] Modifying graphene properties have constrained its substantial utilization in photodetectors.Beyond graphene, 2D TMDCs is the group of van der Waals materials with a vast spectrum of electronic properties including metal-semimetal, semiconductor, and topological insulators due to diversity of structural phase and combination of transition metal and chalcogen atoms. [13] Some remarkable features of TMDCs such as direct bandgap, moderate in-plane mobility, low dark current and strong absorption in the visible region, and reasonable cost make them the most advanced materials for photonics and Few layered transition metal dichalcogenides (TMDCs) are widely used in electrochemical systems due to their unique optical and electronic properties including applications over a large area. Despite the widespread use of 2D layered materials as active components of photoanode, electrochemical conversion studies of few-layered Tantalum diselenide (TaSe 2 ) are still negligible. In view of this, the TaSe 2 nanocrystals (NCs) are successfully synthesized by using the facile liquid-phase exfoliation (LPE) approach. Different physiochemical characterization confirms the inherent physical and optical properties of TaSe 2 NCs. The flexible self-powered photoelectrochemical (PEC) type photodetector based on TaSe 2 NCs achieves the highest photocurrent density (P ph ) of 20.8 µA cm −2 and photoresponsivity (R ph ) of 0.208 mA W −1 in 0.5 m KOH. TaSe 2 NCs demonstrate the excellent self-driven ability and also unveil decent response under applied bias potential in different concentration of KOH electrolyte. Moreover, the electrode shows excellent ON/OFF switching stability up to 1000 s even after the 1 month of storage in the air. Importantly, the photodetector retains the P ph of 15.8 µA cm −2 after 95 bending cycles of 120° angle, displaying the great flexibility of TaSe 2 NCs. This work demonstrates the potential of TaSe 2 NCs for their extended application in PEC-type devices and flexible electronics.

Vertical 1D/2D Heterojunction Architectures for Self-Powered Photodetection Application: GaN Nanorods Grown on Transition Metal Dichalcogenides

“…In order to quantitatively characterize the photovoltaic response, we have calculated two important indicators: responsivity ( R ) and detectivity ( D *) of the vdW heterojunctions photodetectors . The responsivity is evaluated with the formula R = ( I ph – I dark )/ P in S , where I ph and I dark are the measured current under illumination and in the dark, respectively; P in is the incident light power density; S is the active area of the vdW heterojunction photodetector device (8000 μm 2 ). The specific detectivity describes weak detectable signal ability and is defined as D * = R /(2 eI dark / S ) 1/2 , where e is the electron charge.…”

Synthesis of 2D α‐GeTe Single Crystals and α‐GeTe/WSe2 Heterostructures with Enhanced Electronic Performance

“…[9] And as one typical of 2D magnetic materials, CrI 3 displays ferromagnetism in a monolayer, anti-ferromagnetism in a bilayer, and back to ferromagnetism in the trilayer and bulk. [10] Metallic 2D materials (e.g., TaS 2 , [11] TaSe 2 , [12] NbSe 2 , [13] T d -MoTe 2 , [14] and VS 2 , [15] et al) have abstracted considerable research interests for their rich physical properties, such as superconductivity and charge-density waves, etc. For example, NbSe 2 has been reported to exhibit thickness-dependent superconducting properties with a transition temperature increasing from 1.0 to 4.56 K as layer number increases from monolayers to 10 layers.…”

Highly Sensitive and Stable Visible-Light Self-Power Photodetectors Based on Solution-Processed Bi4O5I2

“…Photodetectors, as a kind of photoelectrical conversion device, play a key role in the field of civil and national defense, leading to various applications like optical communication, biomedical imaging, and environment monitoring. , Among the investigated photodetectors, the photoelectrochemical (PEC)-type photodetector has emerged as an inspiring supplement of the photodetector family with various merits including promising photodetection performance, being self-powered, and involving a facile fabrication process. − In the PEC-type photodetector, the separation of photogenerated electron–hole pairs can be achieved owing to the energy barrier between the electrode and the electrolyte . The electrons and holes react with the cations and anions from the electrolyte, respectively, completing the current loop.…”

“…The electrons and holes react with the cations and anions from the electrolyte, respectively, completing the current loop. Thus, the photodetection performance of the PEC-type photodetector can be easily controlled by the chemical composition of the electrolyte. ,, In addition, compared with the heterostructure photodetectors (filed-effect transistors or PN junction), the construction of PEC-type photodetectors is much easier to be implemented . The standard three-electrode-based PEC-type photodetectors were suitable for the comparison of photodetection performance via using the unified potential, while they are challenging in minimization of the device volume and fabrication cost.…”