Electronic structure and absolute band edge position of tetragonal AgInS2 photocatalyst: A hybrid density functional study

Liu, Jianjun; Hua, Enda

doi:10.1016/j.mssp.2015.07.008

Cited by 56 publications

(27 citation statements)

References 48 publications

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“…The CB edge is defined by a lowest-unoccupied MO (LUMO) that has ∼50% In 3+ (5s) character, with ∼30% Ag + (5 s ) character and ∼15% S 2– (3p) character. These results agree well with those computed for bulk AgInS 2 . − …”

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confidence: 90%

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

2018

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A series of Ag1–x Cu x InS2 nanocrystals (NCs) spanning from 0 ≤ x ≤ ∼1 was synthesized by partial cation exchange to identify copper’s contributions to the electronic structure and spectroscopic properties of these NCs. Discrete midgap states appear above the valence band upon doping AgInS2 NCs with Cu+ (small x). Density functional theory calculations confirm that these midgap states are associated with the 3d valence orbitals of the Cu+ impurities. With increasing x, these impurity d levels gradually evolve to become the valence-band edge of CuInS2 NCs, but the highest-occupied orbital’s description does not change significantly across the entire range of x. In contrast with this gradual evolution, Ag1–x Cu x InS2 NC photoluminescence shifts rapidly with initial additions of Cu+ (small x) but then becomes independent of x beyond x > ∼0.20, all the way to CuInS2 (x = 1.00). Data analysis suggests small but detectable hole delocalization in the luminescent excited state of CuInS2 NCs, estimated by Monte Carlo simulations to involve at most about four copper ions. These results provide unique insights into the luminescent excited states of these materials and they reinforce the description of CuInS2 NCs as “heavily copper-doped NCs” in which photogenerated holes are rapidly localized in copper 3d-based orbitals.

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supporting

confidence: 90%

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

2018

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“…These masses are in close agreement with the previous DFT calculations. 46,47 TABLE I. Effective masses of the lowest conduction band and three valence bands fitted from a calculation with the B3LYP hybrid functional.…”

Section: Introductionmentioning

confidence: 99%

Giant Stokes Shifts in AgInS₂ Nanocrystals with Trapped Charge Carriers

et al. 2019

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Nanocrystals of AgInS 2 demonstrate giant Stokes shifts ∼ 1 eV, the nature of which is still not clearly understood. We propose a theoretical model of this phenomenon bringing together several different mechanisms previously considered only separately. We take into account the contribution of electron-electron interaction with the hybrid density functional theory, as well as the renormalization of energy spectrum due to the electron-phonon coupling. Furthermore, we consider the presence of at least one point defect responsible for hole trapping and the formation of a localized polaron state. Our numerical simulations show that photoluminescence due to the recombination of a non-trapped electron and a trapped hole results in the giant Stokes shift in AgInS 2 nanocrystal, which is in close agreement with the recent experimental results.

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“…The work function of a material is a critical parameter commonly used as an intrinsic reference for band alignment. 73 In a general way, the work function can be expressed as follows…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Improvement of Visible-Light Photocatalytic Efficiency in a Novel InSe/Zr₂CO₂ Heterostructure for Overall Water Splitting

et al. 2019

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The unexpected visible-light absorption, low recombination of electron−hole pairs, and high carrier mobility are found in a novel two-dimensional (2D) InSe/Zr 2 CO 2 van der Waals heterostructure for overall water splitting photocatalysis. The photocatalytic mechanism has been systematically investigated using first-principles calculations for the first time. We prove that the 2D InSe/Zr 2 CO 2 heterostructure is a robust and promising visible-light photocatalyst with several distinct advantages, as follows. It has a direct band gap of 1.81 eV, which is a more favorable band gap for visible-light photocatalysis. Its type-II band alignment directly leads to a significant electron−hole separation with electrons (holes) localized in the InSe (Zr 2 CO 2 ) monolayer. The indirect band gap of the InSe (Zr 2 CO 2 ) monolayer further suppresses the electron−hole recombination in it. Naturally, the recombination of the photogenerated electrons and holes is greatly suppressed in the InSe/Zr 2 CO 2 heterostructure, which improves the solar energy utilization effectively. Moreover, a large optical absorption coefficient (10 5 cm −1 ) has been confirmed in the 2D InSe/Zr 2 CO 2 heterostructure with the electron (hole) mobility reaching up to 10 4 (10 3 ) cm 2 V −1 s −1 , which is highly beneficial and desirable for enhancing its photocatalytic efficiency.

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Electronic structure and absolute band edge position of tetragonal AgInS2 photocatalyst: A hybrid density functional study

Cited by 56 publications

References 48 publications

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

Giant Stokes Shifts in AgInS₂ Nanocrystals with Trapped Charge Carriers

Improvement of Visible-Light Photocatalytic Efficiency in a Novel InSe/Zr₂CO₂ Heterostructure for Overall Water Splitting

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Electronic structure and absolute band edge position of tetragonal AgInS2 photocatalyst: A hybrid density functional study

Cited by 56 publications

References 48 publications

Copper’s Role in the Photoluminescence of Ag1–xCuxInS2 Nanocrystals, from Copper-Doped AgInS2 (x ∼ 0) to CuInS2 (x = 1)

Copper’s Role in the Photoluminescence of Ag1–xCuxInS2 Nanocrystals, from Copper-Doped AgInS2 (x ∼ 0) to CuInS2 (x = 1)

Giant Stokes Shifts in AgInS2 Nanocrystals with Trapped Charge Carriers

Improvement of Visible-Light Photocatalytic Efficiency in a Novel InSe/Zr2CO2 Heterostructure for Overall Water Splitting

Contact Info

Product

Resources

About

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

Copper’s Role in the Photoluminescence of Ag_1–xCu_xInS₂ Nanocrystals, from Copper-Doped AgInS₂ (x ∼ 0) to CuInS₂ (x = 1)

Giant Stokes Shifts in AgInS₂ Nanocrystals with Trapped Charge Carriers

Improvement of Visible-Light Photocatalytic Efficiency in a Novel InSe/Zr₂CO₂ Heterostructure for Overall Water Splitting