First-principles studies on switching properties of azobenzene based molecular device

Switching behaviour of stilbene molecular device: a first-principles study

“…As discussed earlier, there is a negligible value of barrier found for the torsion angle (θ = 180 • ) in cis-isomer, but for trans-isomer, the barrier is observed with a reported value of 3 kcal/mol [40]. Previously we have demonstrated the switching properties of cis-trans isomer of azobenzene molecular device [1]. Leyssner and co-worker [16] demonstrated the molecular switches adsorbed on Au(111) and compared the switching behaviour of azobenzene and stilbene derivatives.…”

“…The corresponding retarded and advanced Green's function has been utilized to find the transmission of the stilbene molecular device and it is denoted by G R and G A . The expansion of each term including transmittance and CP on the above equations (3.1) and (3.2) is clearly discussed in our previously reported work [1,30] If V b is set to zero voltage, the transmission energy at Fermi level T(E F ) provides the conductance G = G 0 T(E F ), where G 0 = (2e 2 )/h is the unit of quantum conductance [29,47]. The orbital delocalization along the stilbene molecular system directs to enhance the concentration of free electrons, where it is noticed on particular peak amplitudes P amp in the transmission spectrum of SMS device [48][49][50][51].…”

“…Among the most significant photochromes, azobenzene, stilbene, and their derivatives exhibit reversible photo-induced cis trans isomerization. Moreover, thermodynamically trans-isomer is more stable than cis form [1]. Optical excitation developed by rotation of N=N (C=C) double bond in azobenzene (stilbene) or C inversion in stilbene drives the photoisomerization.…”

“…Usually, the photochromic molecules can be segregated into numerous classes based on their type of chemical process concerned [11]: (1) photo-induced bond cleavages, namely perchlorotoluene; (2) pericyclic reactions, such as electrocyclizations, such as oxazines/-spiropyrans, cycloaditions, diarylethenes and fulgides in aromatic compounds; (3) electron transfers; (4) intramolecular group/hydrogen transfer such as polycyclic and anilsquinones; (5) E/Z isomerizations including stilibenes, azobenzenes and so on. Among these photochromic molecules, the extensively used are stilbenes [12], diarylethenes [13], azobenzenes [1] and oxazines/-spiropyrans [14]. Moreover, oxazines/-spiropyrans, stilbenes and azobenzenes can be switched between the possible two isomers either thermally or photochemically, whereas the diarylethenes can be reverted either electrochemically or photochemically.…”

First-principles studies on band structure and mechanical properties of BiFeO3 ceramics under high pressure

“…The self-consistent convergence of the total energy was obtained in the order of 10 -6 eV/atom. The wave function of bismuth, iron and oxygen atoms were expanded in terms of double zeta polarization (DZP) [20,21] basis set, which mainly depends on the numerical orbitals. The electro-static interaction between the valence electrons and ionic core was represented in terms of ultra-soft pseudo-potentials.…”