A Theoretical Study Of The Strain Accumulation And Electronic Properties Of Highly Strained Benzodithiophene Lattices

Highly strained organic semiconductor materials are of interest to theoretical and experimental researchers because of their high internal strain energy and their special optoelectronic properties.In recent years,a large number of high strain organic semiconductor materials have been reported,such as carbon nanocircles and carbon nanoribbons.However,the synthesis of such high strain materials is difficult and reports on internal molecular strain are more limited compared to the variety of properties and applications brought about by external strain,and the extension and expansion of high strain molecules may open up new opportunities.It has therefore become necessary to investigate how cyclic strain energy accumulates and the factors influencing the accumulation.In this paper,we have chosen to construct three highly strained nanotropic aromatic hydrocarbons from benzodithiophene,and exploit their extensibility to extend and expand these molecules.Using density flooding theory,we have calculated their ground state molecular structure,ring tension energy,intramolecular non-covalent interactions,charge transfer,internal recombination energy and other properties to investigate the growth effect on The effect of growth effects on electronic properties and the pattern of strain energy accumulation are investigated.The following are the conclusions of the study:(i)In the SBDTG-B and SBDTG lateral strain lattice the following conclusions were made.In terms of electronic properties,the hole recombination energy of SBDTG decreases significantly in the same configuration,down to a minimum of 0.066 e V in the molecular configuration ctc-t SBDTG.The ring strain energy increases with increasing number,but not exponentially,due to the influence of non-bonding interactions.In SBDTG,the increasing ring strain energy has a greater effect on the LUMO orbital of the molecule,with the LUMO energy level gradually decreasing with increasing ring strain energy.(ii)The ring strain energy accumulation pattern along the bent conjugated chains and the effect on the ring strain energy accumulation of the molecules when double-ligated are investigated with BBDTG,BBDTG-B and their dimer and trimer and double-ligated PBBDTG and PBBDTG-B molecules.The growth effect is demonstrated by the gradual decrease in hole reorganization energy and electron reorganization energy,the gradual decrease in adiabatic ionization potential and the gradual increase in adiabatic electron affinity energy from a single lattice to a parallel lattice and then to a triple lattice,which demonstrates that the growth effect can effectively enhance the transport properties of the molecule.The ring strain energy is much higher in bilayered molecules due to the increase in torsional strain and non-bonding interactions than the result of linear summation of the two molecules.(iii)When the ring strain energy accumulates perpendicular to the direction of the conjugated chain,the accumulation pattern of the ring strain energy and the effect of the distance of extension on the accumulation of strain energy is explored by two sets of stacking lattice molecules,LBDTG and ALBDTG with the addition of acetylene.The growth effect is still effective in reducing the reorganization energy.These results suggest that the growth effect is an effective way to reduce the intramolecular reorganization energy.In addition,ring strain energy can be accumulated by the growth effect,but the effects of intermolecular distances and linkage sites should be considered,providing theoretical guidance for the experimental design and synthesis of high strain,low reorganization energy crossscale nanomig aromatics.