Graphene-Coated Substrate-Mediated Photoresponse from MoS₂/UCNP Nanohybrid-Based Photodetectors

Abstract

Hybrids of two-dimensional (2D) and 0D nanomaterials offer a wider spectrum of properties than their counterparts. Here, we choose a molybdenum disulfide and NaGdF4:Yb3+, Er3+ upconversion nanoparticle (MoS2-UCNP) nanocomposite (NC) on graphene (G)-coated polydimethylsiloxane (PDMS) and silica/silicon (SiO2/Si) substrates as broadband photodetectors (PDs). The band gap (∼680 nm) limited response of pure MoS2 is broadened by the infrared (980 nm) absorbing UCNPs. Identically fabricated PDs on PDMS and SiO2/Si showed the highest photoresponsivity of 26.18 and 84.52 AW–1, respectively, under 661 nm laser illumination at a density of 1 mW/cm2 at 1 V bias. The MoS2-UCNPs/Graphene/SiO2/Si PD (SiO2/Si PD) showed a response time of ∼100 ms compared to ∼3 s for the PDMS-based PD. The PDMS-based PD showed a reasonably stable photocurrent, decaying by ∼39%, under 250 repetitive cycles of 6.25% bending strain; a maximum decrease of ∼40% of the photocurrent was observed under the 11.11% bending strain compared to the as-prepared flat PD. Both devices could detect signals from domestic appliances such as air conditioner remotes, laser pointers, and cellphone flashlights. The flexible PD based on a hybrid of two nanomaterials having complementary ranges of absorption offers the possibility for better wearable sensors.

Recent progress of UCNPs–MoS2 nanocomposites as a platform for biological applications

“…MoS 2 nanosheets are frequently integrated into composites with diverse materials for a wide range of sensing applications due to their unique optical absorption properties and high specific surface area. 53 Tomar et al 54 coated UCNPs–MoS 2 composites on graphene-coated polydimethylsilane (PDMS) and SiO 2 /Si substrates as broadband photosensors. The sensors exhibited a rapid response time (100 ms) and exceptional stability, maintaining stable photocurrents even after 250 repetitive cycles at 6.25% bending strain, thus paving the way for enhanced wearable sensor technologies (Fig.…”

“…Reproduced with permission. 54 Copyright 2022, American Chemical Society. (B, C) Schematic diagram of MKT's action against cancer.…”

Preparation and Applications of Polydimethylsiloxane‐Based Fluorescent Materials

“…[71] Tomar et al selected MoS 2 absorbing visible light and NaGdF 4 :Yb 3+ , Er 3+ upconversion nanoparticles absorbing NIR light to attach to the surface of PDMS coated with graphene to prepare flexible broadband photodetectors (PDs). [72] The device generated light current under laser irradiation, so it is expected to be used for wearable sensors. However, its response speed and stability are not satisfying enough and still need to be improved.…”

Gold Nanorod-Activated Graphene/MoS2 Nanosheet-Based Photodetectors for Bidirectional Photoconductance

“…13 However, the challenge for these PDs is the slow response time. Most of the reported PDs using hybrid materials show response times in the millisecond−second range, 14 while the commercial semiconductor-based PD devices show extremely fast response times (in picosecond/ microsecond). 15 A major reason for the slowness of the photoresponse is the scattering across the electronically contrasting interfaces present in these hybrids that delay the photogenerated carrier collection at the electrodes.…”