Ahmed Shahnaz, Kalita Dhruba Jyoti
Department of Chemistry, Gauhati University, Guwahati, 781014, India.
Department of Chemistry, Gauhati University, Guwahati, 781014, India.
J Mol Graph Model. 2020 Nov;100:107631. doi: 10.1016/j.jmgm.2020.107631. Epub 2020 Jul 9.
In this paper, we have examined the influence of torsional rigidity on the optoelectronic properties by imposing furan, pyrrole and thiophene unit on the BODIPY-carbazole based donor-acceptor systems employing density functional theory (DFT) formalism. We have designed 12 small conjugated molecules based on the donor (carbazole)-acceptor (BODIPY) approach using furan, pyrrole and thiophene unit as the bridging units. To study the torsional rigidity imparted by the bridging units we have performed potential energy surface (PES) analysis. Our study explores that among the bridging units furan and thiophene impart maximum and minimum rigidity on the systems respectively. Different parameters viz. distortion energy (ΔE), HOMO-LUMO gap (Δ values), ionization potential (IP), electron affinity (EA), bond length alteration (BLA) parameters, dipole moment values, reorganization energies for holes (λ) and electrons (λ), electronic coupling matrix element (V), charge transfer rate (k), hopping mobility (μ), radiative decay rate (k) etc. have been calculated. The absorption and emission spectra of the BODIPY based compounds have been studied using TD-DFT. NTO analysis have also been performed for the dominant electronic transitions. Our calculations predict that compounds possessing pyrrole unit as the bridging unit and compounds in which BODIPY unit is meso substituted with pyrrole unit possesses greater amount of conjugation and as a result exhibit facile charge transport.
在本文中，我们通过采用密度泛函理论（DFT）形式，在基于BODIPY - 咔唑的供体 - 受体体系中引入呋喃、吡咯和噻吩单元，研究了扭转刚度对光电性能的影响。我们基于供体（咔唑） - 受体（BODIPY）方法，使用呋喃、吡咯和噻吩单元作为桥连单元，设计了12个小的共轭分子。为了研究桥连单元赋予的扭转刚度，我们进行了势能面（PES）分析。我们的研究发现，在桥连单元中，呋喃和噻吩分别对体系赋予最大和最小的刚度。计算了不同参数，即畸变能（ΔE）、HOMO - LUMO能隙（Δ值）、电离势（IP）、电子亲和势（EA）、键长改变（BLA）参数、偶极矩值、空穴（λ）和电子（λ）的重组能、电子耦合矩阵元（V）、电荷转移速率（k）、跳跃迁移率（μ）、辐射衰减速率（k）等。使用TD - DFT研究了基于BODIPY的化合物的吸收和发射光谱。还对主要的电子跃迁进行了NTO分析。我们的计算预测，以吡咯单元作为桥连单元的化合物以及BODIPY单元被吡咯单元中取代的化合物具有更大程度的共轭，因此表现出容易的电荷传输。
