Electronic Structure of Crystalline Buckyballs: fcc-C60

Jalali-Asadabadi, S.; Ghasemikhah, E.; Ouahrani, Tarik; Nourozi, Bromand; Bayat-Bayatani, M.; Javanbakht, S; Aliabad, H. A. Rahnamaye; Ahmad, Iftikhar; Nematollahi, Javad; Yazdani-Kachoei, M.

doi:10.1007/s11664-015-4080-2

Cited by 28 publications

(12 citation statements)

References 69 publications

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“…The electronic band structure of FCC-C 60 crystal has been studied using density functional theory and different levels of exchange-correlation energy functional. The calculated band gaps − have been compared to experiment and are listed in Table . FCC-C 60 is a semiconductor with a direct band gap of 2.3 eV, which is much less than that of the diamond structure as well as the computational result from using the GW method .…”

Section: Cluster Assembled Materials (Cams)mentioning

confidence: 99%

Super Atomic Clusters: Design Rules and Potential for Building Blocks of Materials

2018

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Atomic clusters, consisting of a few to a few thousand atoms, have emerged over the past 40 years as the ultimate nanoparticles, whose structure and properties can be controlled one atom at a time. One of the early motivations in studying clusters was to understand how the properties of matter evolve as a function of size, shape, and composition. Over the past few decades, more than 200 000 papers have been published in this field. These studies have not only led to a considerable understanding of this evolution from clusters to crystals, but also have revealed many unusual size-specific properties that make cluster science an interdisciplinary field on its own, bridging physics, chemistry, materials science, biology, and medicine. More importantly, the possibility of creating a new class of materials, composed of clusters instead of atoms as building blocks, has fueled the hope that one can synthesize materials from the bottom-up with unique and tailored properties. This Review focuses on the properties that set clusters apart from their corresponding bulk. Furthermore, this Review describes how different electron-counting rules can lead to the design of stable clusters, mimicking the chemistry of atoms. We highlight the potential of these "superatoms" as building blocks of cluster-assembled materials. Specifically, we emphasize cluster-inspired materials for energy applications. The concluding section includes a summary of the salient features of clusters, potential challenges that remain, and an outlook for the future of cluster science.

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Section: Cluster Assembled Materials (Cams)mentioning

confidence: 99%

Super Atomic Clusters: Design Rules and Potential for Building Blocks of Materials

2018

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“…25,26 Some previous studies 14,16,17,20,21,23 have also shown that devices based on poly-3-hexylthiophene (P3HT) and PCBM blends display a better performance (e.g., a large increase in photocurrent and carrier lifetime) following thermal annealing which alters the fraction of amorphous and microcrystalline PCBM domains, with the formation of PCBM nano-crystalline domains that are crucial for high PCEs. 14,16,27 To date, a large number of studies both in experimental implementations [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] and in theoretical aspects 24,[44][45][46]…”

Section: Introductionmentioning

confidence: 99%

“…50,51 In addition, the photocurrent is also determined to some extent by the absorption coefficient of the photoactive layer. 52 In contrast to the case of solvent-free C 60 and PCBM crystals, whose electronic and optical properties have been widely investigated, 31,[40][41][42][43][44][45][46][47][48][49] there is little information available on the electronic and optical properties of solvated fullerene crystals so far, to the best of our knowledge, and therefore, in order to tailor the efficiency of polymer/fullerene based solar cells in a suitable way for higher PCEs, it is necessary to study the electronic and optical properties of fullerenes co-crystallised with different solvents. To this end, a suitable approach is to use simulations with first-principles density functional theory (DFT) that can provide accurate ground state properties such as energy eigenstates and also allows the calculation of optical absorption spectra.…”

Section: Introductionmentioning

confidence: 99%

Linear-scaling density functional simulations of the effect of crystallographic structure on the electronic and optical properties of fullerene solvates

Han

Boschetto

Krompiec

et al. 2017

Phys. Chem. Chem. Phys.

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In this work, the crystal properties, HOMO and LUMO energies, band gaps, density of states, as well as the optical absorption spectra of fullerene C and its derivative phenyl-C-butyric-acid-methyl-ester (PCBM) co-crystallised with various solvents such as benzene, biphenyl, cyclohexane, and chlorobenzene were investigated computationally using linear-scaling density functional theory with plane waves as implemented in the ONETEP program. Such solvates are useful materials as electron acceptors for organic photovoltaic (OPV) devices. We found that the fullerene parts contained in the solvates are unstable without solvents, and the interactions between fullerene and solvent molecules in C and PCBM solvates make a significant contribution to the cohesive energies of solvates, indicating that solvent molecules are essential to keep C and PCBM solvates stable. Both the band gap (E) and the HOMO and LUMO states of C and PCBM solvates are mainly determined by the fullerene parts contained in solvates. Chlorobenzene- and ortho-dichlorobenzene-solvated PCBM are the most promising electron-accepting materials among these solvates for increasing the driving force for charge separation in OPVs due to their relatively high LUMO energies. The UV-Vis absorption spectra of solvent-free C and PCBM crystals in the present work are similar to those of C and PCBM thin films shown in the literature. Changes in the absorption spectra of C solvates relative to the solvent-free C crystal are more significant than those of PCBM solvates due to the weaker effect of solvents on the π-stacking interactions between fullerene molecules in the latter solvates. The main absorptions for all C and PCBM crystals are located in the ultraviolet (UV) region.

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“…These linear-fits show that the slope predicted by TB-mBJ (−0.995) is closer to the theoretical slope (−1) than those predicted by PBE-GGA (−1.173) and BJ (−1.085). The better performance of the TB-mBJ, ,, which is merely developed to overcome the well-known bandgap-shortcoming of the DFT-based methods, may be related to the value calculated by TB-mBJ for the absolute isotropic shielding in MgTiO 3 . As can be clearly seen from Figure , the latter single value is less scattered from (closer to) the fitted line obtained for TB-mBJ results than the corresponding absolute isotropic shielding values calculated by PBE-GGA and BJ functionals for the MgTiO 3 .…”

Section: Resultsmentioning

confidence: 99%

Microscopic Sources of Solid-State NMR Shielding in Titanate of Alkaline Earth Perovskite Metals

Nematollahi

Jalali-Asadabadi

2018

J. Phys. Chem. C

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Nuclear magnetic resonance (NMR) parameters are calculated and analyzed in a series of titanate of alkaline earth perovskites to explore microscopic sources of their magnetic shieldings using a full-potential-based NMR scheme. In this method, there is no approximation to calculate the induced current density. The slope of the correlation between various approaches and available experimental data is successfully reproduced very close to the required ideal value (−1). Our NMR results are consistent with the experimental data and the available theoretical results calculated by the gauge-including projector augmented-wave (GIPAW) method. Moreover, we have predicted the chemical shifts of the compounds in which their experimental values have not been measured yet. Isotropic and anisotropic chemical shift parameters as well as associated asymmetries are analyzed. The analysis explores the relation between atomic and orbital characters of the valence and conduction bands wave functions as well as the 17O NMR shielding. Our results show that the NMR shielding varies by around 180 ppm through the materials under question. We, in agreement with the results reported on alkali fluorides, show that the variation of the NMR shielding in our investigated alkaline earth titanate perovskites is mostly related to the oxygen p-states. Furthermore, we show that the NMR chemical shifts strongly depend on the shape of the unoccupied titanium-d density of states (DOS) and alkaline-earth metals-d DOSs as well as their locations in the conduction region with respect to the Fermi level. It is also shown that the shielding calculated for the ordinary ice is less by 71.2 ppm than that derived for the water using TB-mBJ.

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Electronic Structure of Crystalline Buckyballs: fcc-C60

Cited by 28 publications

References 69 publications

Super Atomic Clusters: Design Rules and Potential for Building Blocks of Materials

Super Atomic Clusters: Design Rules and Potential for Building Blocks of Materials

Linear-scaling density functional simulations of the effect of crystallographic structure on the electronic and optical properties of fullerene solvates

Microscopic Sources of Solid-State NMR Shielding in Titanate of Alkaline Earth Perovskite Metals

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