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Bhattacharya, Anindya; Bhattacharya, Saswata

doi:10.1103/physrevb.94.094305

Cited by 23 publications

(8 citation statements)

References 38 publications

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“…In our supercell of Ti 16 O 32 the geometric configurations XTi 16 O 31 □ 1 , XTi 16 O 32 and X 2 Ti 16 O 31 □ 1 represent respectively (X) O , (XO) O and (X 2 ) O . For this purpose, we have adopted an iterative strategy 46 : starting with the Ti 16 O 32 supercell, we first identified the most favorable sites for the O-□ by scanning over all possible sites. We find that, since they belong to the same symmetry point, all the atomic sites are equivalent.…”

Section: Resultsmentioning

confidence: 99%

Stability of non-metal dopants to tune the photo-absorption of TiO2 at realistic temperatures and oxygen partial pressures: A hybrid DFT study

Basera

Saini

Arora

et al. 2019

Sci Rep

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TiO 2 anatase is considered to play a significant importance in energy and environmental research. However, for developing artificial photosynthesis with TiO 2 , the major drawback is its large bandgap of 3.2 eV. Several non-metals have been used experimentally for extending the TiO 2 photo-absorption to the visible region of the spectrum. It’s therefore of paramount importance to provide theoretical guidance to experiment about the kind of defects that are thermodynamically stable at a realistic condition (e.g. Temperature ( T ), oxygen partial pressure ( ), doping). However, disentangling the relative stability of different types of defects (viz. substitution, interstitial, etc.) as a function of charge state and realistic T , is quite challenging. We report here using state-of-the-art first-principles based methodologies, the stability and meta-stability of different non-metal dopants X (X = N, C, S, Se) at various charge states and realistic conditions. The ground state electronic structure is very accurately calculated via density functional theory with hybrid functionals, whereas the finite T and effects are captured by ab initio atomistic thermodynamics under harmonic approximations. On comparing the defect formation energies at a given T and (relevant to the experiment), we have found that Se interstitial defect (with two hole trapped) is energetically most favored in the p-type region, whereas N substitution (with one electron trapped) is the most abundant defect in the n-type region to provide visible region photo-absorption in TiO 2 . Our finding validates that the most stable defects in X doped TiO 2 are not the neutral defects but the charged defects. The extra stability of is carefully analyzed by comparing the individual effect of bond-making/breaking and the charge carrier trapping energies.

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Section: Resultsmentioning

confidence: 99%

Stability of non-metal dopants to tune the photo-absorption of TiO2 at realistic temperatures and oxygen partial pressures: A hybrid DFT study

Basera

Saini

Arora

et al. 2019

Sci Rep

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“…As a first step, a systematic scanning of potential energy surface (PES) is done via cascade genetic algorithm (cGA) [57][58][59] approach to obtain the global minimum (GM) configurations of Ni 4 O x (CH 4 ) y clusters. Subsequently, we have employed ab initio atomistic thermodynamics (aiAT) 57,60,61 in the framework of DFT to determine the thermodynamic stability of those configurations under operational conditions. To incorporate the anharmonicity in the vibrational free energy contribution to the configurational entropy, we evaluate the excess free energy of the clusters numerically by thermodynamic integration method 62 with ab initio molecular dynamics (aiMD) simulation inputs.…”

Section: Introductionmentioning

confidence: 99%

Theoretical insights into C–H bond activation of methane by transition metal clusters: the role of anharmonic effects

2021

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“…temperature (T ), oxygen partial pressure (p O 2 ), doping). 12,[50][51][52][53] This facilitates us to estimate the probability of occurrence of these (meta)stable structures. Following this, a few clusters, that are thermodynamically stable as well as possess active sites, are selected and their electronic structures are accurately analyzed using GW calculations.…”

Section: Introductionmentioning

confidence: 99%

Metastability Triggered Reactivity in Clusters at Realistic Conditions: A Case Study of N-doped (TiO$_2$)$_n$ for Photocatalysis

Saini,

Basera,

Kumar

et al. 2020

Preprint

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Here we report a strategy, by taking a prototypical model system for photocatalysis (viz. N-doped (TiO 2 ) n clusters), to accurately determine low energy metastable structures that can play a major role with enhanced catalytic reactivity. Computational design of specific metastable photocatalyst with enhanced activity is never been easy due to plenty of isomers on potential energy surface. This requires fixing various parameters viz. (i) favorable formation energy, (ii) low fundamental gap, (iii) low excitation energy and (iv) high vertical electron affinity (VEA) and low vertical ionization potential (VIP). We validate here by integrating several first principles based methodologies that consideration of the global minimum structure alone can severely underestimate the activity. As a first step, we have used a suite of genetic algorithms [viz. searching clusters with conventional minimum total energy ((GA) E ); searching clusters with specific property i.e. high VEA ((GA) EA P ), and low VIP ((GA) IP P )] to

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Unraveling the role of vacancies in the potentially promising thermoelectric clathratesBa8ZnxGe46−x−y□y

Cited by 23 publications

References 38 publications

Stability of non-metal dopants to tune the photo-absorption of TiO2 at realistic temperatures and oxygen partial pressures: A hybrid DFT study

Stability of non-metal dopants to tune the photo-absorption of TiO2 at realistic temperatures and oxygen partial pressures: A hybrid DFT study

Theoretical insights into C–H bond activation of methane by transition metal clusters: the role of anharmonic effects

Metastability Triggered Reactivity in Clusters at Realistic Conditions: A Case Study of N-doped (TiO$_2$)$_n$ for Photocatalysis

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