KAgSe: A New Two-Dimensional Efficient Photovoltaic Material with Layer-Independent Behaviors

Abstract

Recent advances in the development of two-dimensional (2D) materials have stimulated people’s interest and enthusiasm to discover new kinds of 2D functional materials. In this paper, we propose a novel 2D layered semiconductor KAgSe using the first-principles calculation method, which displays excellent photovoltaic properties with proper direct band gap and significant carrier mobility. By evaluating the cohesive energy, vibrational phonon spectrum, and temporal evolution of the total energy at a high temperature of 500 K, the KAgSe monolayer is proved to be stable. Finite cleavage energy comparable to that of black phosphorus implies the feasibility of mechanical exfoliation of a KAgSe monolayer from the bulk. Layered KAgSe shows a ∼1.5 eV direct band gap, which is roughly independent of the number of layers. Remarkable optical absorption coefficients in the visible light region and significant carrier mobilities reveal a favorable application prospect of layered KAgSe in photovoltaic devices. Especially, the layer-independent optical absorption provides enormous convenience and less difficulty in experimental fabrication of photoelectronic devices which are based on finite layer KAgSe. To further explore the photovoltaic behaviors, the polarization angle-related photocurrent is evaluated for the KAgSe monolayer-based nanodevice by irradiating a beam of linearly polarized light to the scattering region. Moreover, large photon responsivity and external quantum efficiency are also obtained for the KAgSe monolayer.

Novel Two-Dimensional Layered MoSi2Z4 (Z = P, As): New Promising Optoelectronic Materials

“…For both MoSi 2 P 4 and MoSi 2 As 4 , the photocurrent is roughly symmetrical with respect to θ = 90 • , and reaches maximums at θ = 0 • and θ = 180 • . Similar symmetrical distribution of photocurrent with polarization angle was also reported for monolayer KAgSe-based 2D optoelectronic device [40].…”

“…For bilayer MoSi 2 Z 4 , the rather weak interlayer vdW interaction makes the Mo atoms at the up layer and those at the down layer have nothing to do with each other, and thus the band gap is very close to that of the monolayer. Similar layer number independent bandgap behavior has also been found in layered 2D KAgSe [40]. The layer number independent electronic properties provide enormous convenience and less difficulty in experimental fabrication of finite layer MoSi 2 Z 4 -based electronic devices.…”

“…R ph of monolayer MoSi 2 P 4 and MoSi 2 As 4 in the visible light region are 0.060 AW −1 and 0.046 AW −1 , respectively, which are the same order as those of MoS 2 (0.016 AW −1 ) and monolayer chalcogenides (0.035 AW −1 for GeS and 0.075 AW −1 for SnS), while two orders higher than that of graphene (5 × 10 −4 AW −1 )[52]. τ eqe of monolayer MoSi 2 P 4 and MoSi 2 As 4 in the visible light region can reach 18.60% and 13.33%, respectively, which are comparable to those of KAgSe (17.92%)[40] and monolayer chalcogenides (10.27% for GeS and 22.01% for SnS)[53]. In addition, R ph and τ eqe of monolayer MoSi 2 Z 4 are greatly increased within the whole light region, ie, 0.143 AW −1 and 64.26% for MoSi 2 P 4 , 0.098 AW −1 and 41.16% for MoSi 2 As 4 .…”

First-principles study of structural stability, electronic properties and lattice thermal conductivity of KAgX (X = S, Se, Te)

“…Recently (2018), Wang et al [13] explored KAgSe and reported it to be an efficient photovoltaic material in 2D, possessing layer-independent behaviours. According to these authors, KAgSe is a stratified material having alternating layers of K-Se-Ag-Se-K along the (001) direction.…”

Promising photovoltaic efficiency of a layered silicon oxide crystal Si3O

“…Together with these impressive developments in materials predictions, recent progresses in the data-driven sciences such as text-mining and natural language processing for synthesis of inorganic materials [16] may further accelerate the computer-aided materials discovery. For 2D materials, high-throughput materials search algorithms [8,9,17,18] have been used for screening the optimal material candidates for solar cell applications [17][18][19][20][21]. Considering current domination of silicon solar cells, however, a suitable 2D silicon material that is readily applicable for harvesting solar light is still lacking.…”