A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

Abstract

Two-dimensional (2D) tungsten disulfide (WS2) has inspired great efforts in optoelectronics, such as in solar cells, light-emitting diodes, and photodetectors. However, chemical vapor deposition (CVD) grown 2D WS2 domains with the coexistence of a discontinuous single layer and multilayers are still not suitable for the fabrication of photodetectors on a large scale. An emerging field in the integration of organic materials with 2D materials offers the advantages of molecular diversity and flexibility to provide an exciting aspect on high-performance device applications. Herein, we fabricated a photodetector based on a 2D-WS2/organic semiconductor materials (mixture of the (Poly-(N,N′-bis-4-butylphenyl-N,N′-bisphenyl) benzidine and Phenyl-C61-butyric acid methyl ester (Poly-TPD/PCBM)) heterojunction. The application of Poly-TPD/PCBM organic blend film enhanced light absorption, electrically connected the isolated WS2 domains, and promoted the separation of electron-hole pairs. The generated exciton could sufficiently diffuse to the interface of the WS2 and the organic blend layers for efficient charge separation, where Poly-TPD was favorable for hole carrier transport and PCBM for electron transport to their respective electrodes. We show that the photodetector exhibited high responsivity, detectivity, and an on/off ratio of 0.1 A/W, 1.1 × 1011 Jones, and 100, respectively. In addition, the photodetector showed a broad spectral response from 500 nm to 750 nm, with a peak external quantum efficiency (EQE) of 8%. Our work offers a facile solution-coating process combined with a CVD technique to prepare an inorganic/organic heterojunction photodetector with high performance on silicon substrate.

Colloidal InSb Quantum Dots/Organic Integrated Bulk Heterojunction for Fast and Sensitive Near‐Infrared Photodetectors

“…It is to note that poly-TPD can improve the obtained InSb/organic blend thin film quality, and the introduction of the PCBM with HOMO level as low as À6.1 eV can suppress the leakage current. [37,38] Further efforts are required to improve the charges collection efficiency through improving carrier mobility in InSb CQDs solids, suppressing nonradiative recombination, and optimizing hybrid device architecture.…”

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

“…[ 144 ] On the contrary, the symmetric electrode on Poly‐TPD:PCBM with both BHJ and WS 2 for light‐absorbing. [ 146 ]…”

Ti3C2Tx MXene‐RAN van der Waals Heterostructure‐Based Flexible Transparent NIR Photodetector Array for 1024 Pixel Image Sensing Application

“…Organic photosensitive materials with controlled thickness, superior flexibility, and high transmittance can easily attain uniform coverage in target areas and cooperate with conductive electrodes to fulfill the procedure of regional highly transparent device arrays. [11][12][13][14] Moreover, the existence of large electronegative N and O atoms in some organic photosensitive materials provide suitable conditions for the formation of noncovalent bonds. Looking for a specific conductive electrode that offers the formation possibility of heterostructure and noncovalent bonds with the active material could accelerate the separation of electron and hole, optimize and raise the performance of the material itself, in the meantime, make the two parts become more tightly.…”