Non-covalent functionalization of WS₂ monolayer with small fullerenes: tuning electronic properties and photoactivity

Abstract

Atomically thin two-dimensional transition metal dichalcogenides (TMDCs) heterostructures have recently attracted growing interest due to their massive potential in solar energy applications due to their band gap in the visible spectral range and extremely strong light-matter interactions. Herein, heterostructures composed of WS2 and MoS2 monolayers, as representative TMDCs, with small fullerenes (B12 and C20) are investigated to explore their applications in solar energy conversion using first principles calculations based on density functional theory (DFT). The WS2 (MoS2) monolayer and fullerene form a van der Waals (vdW) heterostructure. Compared to pure monolayers, the heterostructures have a smaller band gap, which favours enhancing visible light absorption. The amount of charge transfer at the interface induced by vdW interactions depends on the type of fullerene. Most importantly, a type-II staggered band alignment is formed between WS2 (MoS2) and fullerene with the latter possessing the higher electron affinity which results in the robust separation of photoexcited charge carriers between them. These results indicate that the electronic properties and photoactivity of TMDCs monolayers can be tuned by non-covalent coupling with small fullerenes, thus meeting the needs of various applications.

Recent Progress in the Development of Semiconductor‐Based Photocatalyst Materials for Applications in Photocatalytic Water Splitting and Degradation of Pollutants

“…In photocatalytic systems, fullerene can create a space potential difference to enrich the separation and migration of the photogenerated charge carriers, as well as tuning the band gap . The amount of charge transfer in WS 2 /fullerenes and MoS 2 /fullerene (C 60 , C 26 , and C 20 ) heterostructures was found to depend on the nature of the fullerene. In addition, a type‐II staggered band alignment, which was formed in the MoS2/C20 and WS2/fullerenes heterostructures, contributed to the enriched photocatalytic performance and the reduced charge recombination.…”

Interfacial Interaction between Boron Cluster and Metal Oxide Surface and Its Effects: A Case Study of B20/Ag3PO4 van der Waals Heterostructure

“…In this regard, boron-nanostructure-based heterostructures or devices with desirable performance for various fields are worth the expectation, similar to its analogues of carbon, which have widely been used in recent years. Carbon-based heterostructures are the focus of intense research in the past decades and have revealed that the interfacial interaction is one of the key factors to govern their properties and applications. , However, the investigations of boron nanostructures are so far concentrated in their structures and related properties, and even seldom research studies focus on their growth on substrates, , let alone their interaction and its effect. This impedes not only the experimental preparation of low-dimensional boron structures but also the design of novel boron-based devices.…”

Recent Progress on Fullerene-Based Materials: Synthesis, Properties, Modifications, and Photocatalytic Applications

“…Then, fullerene could enhance the light absorption (both UV and visible light) because it is an excellent photo-response material (300~700 nm), wherein elevated light energy utilization excites more electrons from VB to CB [ 33 , 34 ]. In respect to photo-response characteristics, it must also be mentioned that fullerene could not shift the adsorption edge of pristine photocatalyst unless the introduction of fullerene changed the structure of semiconductor [ 35 , 36 , 37 ]. In other words, if the fullerene does not change the crystalline structure of semiconductor in the synthesis procedure, which was typically affected by a stronger bonding force other than simply physically blending, it could not change the conduction band (Eg) at all.…”