Himanshu Chakraborty

Development of inexpensive and efficient photo- and electro-catalysts is vital for clean energy applications.

Hexagonal borocarbonitrides (BCN) are a class of 2D materials, which display excellent catalytic activity for water splitting. Here, we report analysis of thermal stability, phonons and thermal conductivity of BCN monolayers over a wide range of temperatures using classical molecular dynamics simulations. Our results show that in contrast to the case of graphene and boron nitride monolayers, the out-of-plane phonons in BCN monolayers induce an asymmetry in the phonon density of states at all temperatures. Despite possessing lower thermal conducting properties compared to graphene and BN monolayers, the BCN nanosheets do not lose thermal conductivity as much as graphene and BN in the studied temperature range of 200-1000 K, and thus, the BCN nanosheets are suitable for thermal interface device applications over a wide range of temperatures. Besides their promising role in water splitting, the above results highlight the possibility of expanding the use of BCN 2D materials in thermal management applications and thermoelectrics.

Hexagonal borocarbonitrides (BCN) are a class of 2D materials, which display excellent catalytic activity for water splitting.

Magnetic-energy harvesting in centimeter-sized free-standing (BEDT-TTF)C₆₀ charge-transfer single crystal is demonstrated. The crystal shows sensitive magnetic-, thermal-, and mechanical-sensing ability, with an excellent piezoresistance coefficient of −5.1 × 10⁻⁶ Pa⁻¹. The self-powered sensing performance, together with its solution processability and flexibility, endow it with the capability of driving a new generation of noncontact magnetic-energy harvesting and sensing technologies.

In this paper, optical and electronic properties of diamond shaped graphene quantum dots (DQDs) have been studied by employing large-scale electron-correlated calculations. The computations have been performed using the \pi-electron Pariser-Parr-Pople model Hamiltonian, which incorporates long-range Coulomb interactions. The influence of electron-correlation effects on the ground and excited states has been included by means of the configuration-interaction approach, used at various levels. Our calculations have revealed that the absorption spectra are red-shifted with the increasing sizes of quantum dots. It has been observed that the first peak of the linear optical absorption, which represents the optical gap, is not the most intense peak. This result is in excellent agreement with the experimental data, but in stark contrast to the predictions of the tight-binding model, according to which the first peak is the most intense peak, pointing to the importance of electron-correlation effects.

The technological importance of higher acenes has led to resurgence of interest in synthesizing higher acenes such as octacene, nonacene etc. Recently, Tönshoff and Bettinger [2010 Angew. Chem. Int. Ed. 49 4125] have synthesized octacene and nonacene. Motivated by their work, we have performed large-scale calculations of linear optical absorption of octacene and nonacene. Methodology adopted in our work is based upon Pariser-Parr-Pople model (PPP) Hamiltonian, along with large-scale multi-reference singles-doubles configuration interaction (MRSDCI) approach.

The technological importance of higher acenes has led to resurgence of interest in synthesizing higher acenes such as octacene, nonacene etc.[1] Recently, Tonshoff and Bettinger have synthesized octacene and nonacene [2]. Motivated by their work, we have performed large scale calculations of linear optical absorption of octacene and nonacene and compared the results with their experimental work. Methodology adopted in our work is based upon Pariser-Parr-Pople model (PPP) Hamiltonian, along with large-scale multi-reference singles-doubles configuration interaction (MRSDCI) approach.