Adsorption of alanine with heteroatom substituted fullerene for solar cell application: A DFT study

C₂₀ is the most important fullerene cage and alanine is the simplest representation of a backbone unit of the protein. The absorption feasibility of alanine molecule in the Si-doped C₂₀ and B-doped C₂₀ fullerenes has been studied based on calculated electronic properties of fullerenes using density functional theory (DFT). In this work, we explore the ability of Si-doped C₂₀, B-doped C₂₀ fullerene to interact with alanine at the DFT-B3LYP/6-31G, RHF level of theory. We find that noticeable structural change takes place in C₂₀ when one of its carbon is substituted with Si or B. The molecular geometry, electronic properties and vibrational analysis have also been performed on the title compounds. The NMR study reveals the aromaticity of the pure and doped fullerene compounds. Stability of the doped fullerene - alanine compound arises from hyper conjugative interactions. It leads to one of the major property of bioactivity, charge transfer and delocalization of charge and this properties has been analyzed using Natural Bond Orbital (NBO) analysis. The energy gap of the doped fullerene reveals that there is a decrease in the size of energy gap significantly, making them more reactive as compared to C₂₀ fullerene. Theoretical studies of the electronic spectra by using time - dependent density functional theory (TD-DFT) method were helpful to interpret the observed electronic transition state. We aim to optimize the performance of the solar cells by altering the frontier orbital energy gaps. Considering all studied properties, it may be inferred that the applicability of C₂₀ fullerene as the non-linear optical (NLO) material and its NLO property would increase on doping fullerene with Si and B atom. Specifically C₁₉Si would be better among them.

Density functional theory (DFT) investigations on doped fullerene with heteroatom substitution

Structures and stabilities of dodecahedral fullerene C19X (X=Ni, Ti) and C20 have been investigated by quantum chemical calculations based on density functional theory. The geometrical structures, relative stabilities, dielectric constant of the doped cages were studied systematically and compared with those of the fullerene C20 cage. A series of dodecahedral functionalized derivatives have been studied at the B3LYP/6-31G level of density functional theory (DFT). The relative and formation energies of compounds, Mulliken charges, occupancy, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), the HOMO-LUMO band gap and chemical potential (μ) were calculated. The doping effect is discussed in terms of the change in the CC bond length and total dipole moment. The obtained result indicates that the CC bond length increases as a result of doping. The NBO analysis showed that there is a hyper conjugative interaction between the hetero atoms such as titanium and nickel lone-pair electron of doped fullerene with bonding and antibonding (σ(∗)) orbital of carbon atom of fullerene. The stability of the molecule, arising from charge delocalization, has been analyzed using Natural Bond Orbital (NBO) analysis. The nucleus - independent that more negative NICS values in doped fullerene than those of C20. The condensed Fukui Function and the newly introduced the atomic descriptors S (fk) to determine the local reactive sites of the molecular systems during electrophilic, nucleophilic and radical attacks have been calculated for the fullerene C20 compound.