1T‴ Transition-Metal Dichalcogenides: Strong Bulk Photovoltaic Effect for Enhanced Solar-Power Harvesting

Abstract

Ferroelectrics is expected to be an alternative to traditional solar cells, because its bulk photovoltaic effect (BPVE) may overcome the Shockley–Queisser limit. Here, we propose that a family of polar materials without centrosymmetry, distorted 1T (1T′′′) transition-metal dichalcogenides, shows a large BPVE in the infrared and visible light due to their moderate band gaps based on density-functional-theory (DFT) calculations. We find that the BPVEs in bulks are much higher than those in monolayers because of the smaller band gaps and more delocalized valence band states. We further show that strain engineering serves as an efficient strategy to enhance the BPVE of 1T′′′-MoS2 bulk. The shift-current responses in the bulks spotlight their potential for applications into solar energy harvesting. This work provides the theoretical evidence of BPVE in 1T′′′ transition-metal dichalcogenides and guidance on the design of novel materials with an enhanced BPVE for green-energy technologies.

Large Bulk Piezophotovoltaic Effect of Monolayer 2H-MoS2

“…34 Shift current was predicted in the distorted 1T‴ phase, where it was found to be tunable using biaxial strain. 17 The 2H phase of monolayer MoS 2 shown in Figure 1a has a direct band gap, bright photoluminescence, and tunable electronic propensities. 29,35−38 It is noncentrosymmetric, so it can also exhibit nonlinear optical phenomena although the structure is nonpolar.…”

Shift-current response as a probe of quantum geometry and electron-electron interactions in twisted bilayer graphene

“…Specifically, the magnitude of such QG effects is sensitive to the change in average position of Bloch wavefunctions within the unit cell [17]. Previous works that studied shift current response in bilayer graphene and TMDs [34,[50][51][52][53] predicted a strong effect due to their non-zero Berry curvature profile.…”

Novel perovskite solar cell with Distributed Bragg Reflector

“…Different approaches [ 1 , 2 ], techniques [ 3 – 5 ], and methods [ 6 , 7 ] have been investigated, demonstrated, and reported to improve the design and geometry of the device that can be used to generate electricity and can be utilized as a replacement to typical non-environmental friendly methods [ 8 ] that have been used to generate power. Solar cell technology is an inexhaustible, reliable, and commercialized technology that has been considered by the photovoltaic community to generate electric power through the photovoltaic effect [ 9 , 10 ].…”