2D van der Waals Heterojunction of Organic and Inorganic Monolayers for High Responsivity Phototransistors

Abstract

Van der Waals (vdW) heterostructures composing of organic molecules with inorganic 2D crystals open the door to fabricate various promising hybrid devices. Here, a fully ordered organic self-assembled monolayer (SAM) to construct hybrid organic-inorganic vdW heterojunction phototransistors for highly sensitive light detection is used. The heterojunctions, formed by layering MoS 2 monolayer crystals onto organic [12-(benzo[b]benzo[4,5] thieno[2,3-d]thiophen-2-yl)dodecyl)]phosphonic acid SAM, are characterized by Raman and photoluminescence spectroscopy as well as Kelvin probe force microscopy. Remarkably, this vdW heterojunction transistor exhibits a superior photoresponsivity of 475 A W −1 and enhanced external quantum efficiency of 1.45 × 10 5 %, as well as an extremely low dark photocurrent in the pA range. This work demonstrates that hybridizing SAM with 2D materials can be a promising strategy for fabricating diversified optoelectronic devices with unique properties.

Structures, Properties, and Device Applications for [1]Benzothieno[3,2‐b]Benzothiophene Derivatives

“…[ 11,211 ] Self‐assembled BTBT phosphonic acid monolayer (BTBT‐SAM) stacked on the MoS 2 monolayer to construct the type‐II heterojunction with the photoresponsivity of 475 A W −1 . [ 212 ] As a promising material in photodetectors, C8‐BTBT possesses a very important feature including negligible response in visible range but high sensitivity in UV range, which enable to prepare high‐performance UV photodetectors. Tu et al applied C8‐BTBT/DFPPO composite thin film as the active layer and the devices could detect UV signals at the wavelength within 350 nm.…”

Atomic and structural modifications of two-dimensional transition metal dichalcogenides for various advanced applications

“…BTBT provides effective charge transfer via π–π interactions and successfully eliminates recombination and charge scattering. 161 …”

Recent Progress in 2D Inorganic/Organic Charge Transfer Heterojunction Photodetectors

“…Starting from the quantum dot (QDs), Konstantatos et al merged PbS QDs and graphene to promote the responsivity up to 10 7 A W −1 based on photogating. [102] Therefore, a planar CT heterojunction is adopted into 2D inorganic/organic initial devices, including dye, [103][104][105] polymer, [106][107][108][109][110] small molecule, [54,58,59,[111][112][113][114][115][116] photocatalysts, [117] chlorophyll, [118] organicinorganic perovskite, [119] COF, [83] and MOF. [84,120] Figure 4.…”

“…i) The crystal schematic illustration of MoS 2 /BTBT with self-assembly process [116]. j) The photoresponse characterization with various power densities [116]. Reproduced with permission [116].…”