Vol.:(0123456789) 1 3 Applied Physics A ( 2020) 126:130 https://doi.org/10.1007/s00339-020-3300-7 Investigating the electronic and nonlinear optical properties of fullerene by substituting N, P, As, and Sb in the lattice structure: a DFT study Samir Thakur 1  · Sankar M. Borah 1  · Ashok Singh 2  · Nirab C. Adhikary 3 Received: 20 September 2019 / Accepted: 8 January 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract In this article, we used density functional theory (DFT) to investigate the structural, electronic and nonlinear optical proper- ties of N, P, As and Sb doped fullerene. The average polarizability and hyperpolarizability is signifcantly improved when these impurities are substituted individually in the (C60) lattice structure. The maximum hyperpolarizability is calculated for N-doped fullerene (3541.27 au) followed by P-doped fullerene (259.71 au), As-doped fullerene (102.52 au) and Sb-doped fullerene (32.06 au). A similar trend is observed and the polarizability is found to decrease monotonically. Both the polariz- ability and hyperpolarizability values are found to decrease with an increasing energy gap of the doped fullerene. N-Doped fullerene has the lowest energy gap (1.28 eV) followed by P-doped fullerene (1.94 eV), As-doped fullerene (2.02 eV) and Sb-doped fullerene (2.10 eV). The lowest energy gap minimizes the excitation energy and thus improves the nonlinear optical response. From the calculation of time-dependent-DFT (TD-DFT), it is observed that the maximum absorption wavelength of N-doped fullerene, which is about 830 nm, is shifted towards the longer wavelength at the infrared region in the case of P, As, and Sb-doped fullerenes. The results obtained through this study will help encourage the potential utilization of the metal-free doped-fullerene systems as a form of unique optical devices, thermal radiation detector, etc. Keywords Fullerene · Density function theory · Partial density of states · Energy gap · Polarizability · Hyperpolarizability 1 Introduction Through a previous couple of years, the design of new mate- rials with remarkable non-linear optical (NLO) properties has gained signifcant attention due to their many appli- cations in optoelectronics, photonic devices, bio-sensing, imaging, optical telecommunications, semiconductors, second harmonic generation, etc. [1–8]. Materials, which can alter the fundamental parameters of an incident optical beam, such as phase, amplitude, frequency, etc., received tremendous attention for nonlinear optical activity (NLO). A variety of organic, inorganic, organometallic and poly- mer materials exist which show the NLO activity. A wide range of methods have already been discovered in the litera- ture (such as electron push–pull mechanism, metal–organic assemblies) to further improve the NLO properties of vari- ous materials. Hyperpolarizability also increases due to excess difuse electrons [9]. Alkali metal atoms have sig- nifcant contribution to make the molecular structure elec- tron rich system. These excessive electrons received from metals reduce the excitation energy and, therefore, increases the NLO response [10–13]. Substituting is one of the most efcient methods for altering the electronic properties of the structure to have a sufcient number of electrons and holes [14–18]. The literature shows numerous articles that review information about the excess electron approach employed to have large hyperpolarizability values [6–8]. For example, Niu et al. [6] observed the large frst-order Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00339-020-3300-7) contains supplementary material, which is available to authorized users. * Nirab C. Adhikary nirab_iasst@yahoo.co.in 1 Physical Science Division, Department of Applied Sciences, Gauhati University, Guwahati, Assam 781014, India 2 Department of Physics, Science College, BTC, Kokrajhar, Assam 783370, India 3 Physical Sciences Division, Institute of Advanced Study in Science Technology, Paschim Boragaon, Garchuk, Guwahati, Assam 781035, India