Boron Subphthalocyanine Based Molecular Triad Systems for the Capture of Solar Energy

Unraveling the Impact of Flexibility and Solvent Effects on the UV-Vis Absorption Spectrum of Subphthalocyanine in Liquid Chloroform within the Born-Oppenheimer Molecular Dynamics Approach

A study based on Born-Oppenheimer molecular dynamics (BOMD) of the subphthalocyanine (SubPc) with a chloride attached to the central boron atom was carried out. The BOMD simulation is used to access the dynamic evolution of the SubPc in liquid chloroform, and the electronic absorption spectrum is calculated using the Time-Dependent Density Functional Theory (TDDFT) considering explicit solvent models. We show that the conformational changes and solvent effects produce a red shift of the Q-band, where the largest contribution is due to the geometry changes of the symmetric structure of SubPc. A large splitting (0.2 eV) of the first electronic transition is also described, and it originates as a shoulder in the Q-band, which according to previous experimental studies is attributed to a vibronic origin. The red shift is obtained in agreement with experiment within less than 0.1 eV. The splitting is a consequence of the symmetry breaking in the SubPc central ring structure occurring during the molecular dynamics, with a significant contribution to the large red shift and the broadening of the spectrum.

Machine learning the frontier orbital energies of SubPc based triads

Organic photovoltaic devices are promising candidates for efficient energy harvesting from sunlight. Designing new dye molecules suitable for such devices is a challenging task restricted by the rapid increase of computational cost with system size. Solar cell material properties are closely related to the electronic structure of the dye, and an effective molecular orbital energy screening method for a family of dyes is therefore desired. In this work, a machine learning approach is used to sort through the chemical space of peripheral double-substituted boron-Subphthalocyanine dyes. A database of 12,102 PM6 optimized structures was built and for each of the structures time-dependent density functional theory (LC-[Formula: see text]HPBE/6-31+G(d)) calculations were performed. We investigated the changes of the molecular orbital energies of the molecular orbitals related to reduction and oxidation of the compounds. With the Electrotopological-state index moleculear representation all the tested algorithms, Support Vector Machine, Random Forest Regression, Neural Network, and Simple Linear Regression, captured the calculated frontier orbital energies with a prediction root-mean-square-error in the order of 0.05 eV. Finally, frontier orbital energies were predicted for more than 40,000 new structures by the trained Support Vector Machine algorithm. Compared to the parent boron-Subphthalocyanine structure, 237 and 132 functionalized dyes were predicted to have upshifted molecular orbital energies using the Electrotopological-state index and OneHot encoding feature vector, respectively. Out of 27 investigated donor and acceptor ligands, the acetamide and hydroxyl ligands gave rise to the desired increase in frontier molecular orbital energy.

Recent advances in subphthalocyanines and related subporphyrinoids

Subporphyrinoids constitute a class of extremely versatile and attractive compounds. Herein, a comprehensive review of the most recent advances in the fundamentals and applications of these cone-shaped aromatic macrocycles is presented.

Dual color triads: synthesis, photophysics and applications in live cell imaging

Fluorescent labels and probes constitute an important class of organic materials used in the development of sensor systems and imaging platforms for various chemical and molecular biology applications.

One-Pot Synthesis of π-Extended Fluorenone-Fused Subphthalocyanines

A family of inherently chiral nonplanar aromatic chromophores, comprising Subphthalocyanines bearing fluorenone-fused units (SubFcs), have been prepared by an innovative one-pot synthesis, which relies on the standard cross-cyclotrimerization of phthalonitriles followed by intramolecular Friedel-Crafts acylation. Their Q-band absorption experiences a ca. 20 nm red shift per fused fluorenone as a consequence of the enlarged conjugated π-system.

Nonfullerene Acceptor Molecules for Bulk Heterojunction Organic Solar Cells

The bulk-heterojunction blend of an electron donor and an electron acceptor material is the key component in a solution-processed organic photovoltaic device. In the past decades, a p-type conjugated polymer and an n-type fullerene derivative have been the most commonly used electron donor and electron acceptor, respectively. While most advances of the device performance come from the design of new polymer donors, fullerene derivatives have almost been exclusively used as electron acceptors in organic photovoltaics. Recently, nonfullerene acceptor materials, particularly small molecules and oligomers, have emerged as a promising alternative to replace fullerene derivatives. Compared to fullerenes, these new acceptors are generally synthesized from diversified, low-cost routes based on building block materials with extraordinary chemical, thermal, and photostability. The facile functionalization of these molecules affords excellent tunability to their optoelectronic and electrochemical properties. Within the past five years, there have been over 100 nonfullerene acceptor molecules synthesized, and the power conversion efficiency of nonfullerene organic solar cells has increased dramatically, from ∼2% in 2012 to >13% in 2017. This review summarizes this progress, aiming to describe the molecular design strategy, to provide insight into the structure-property relationship, and to highlight the challenges the field is facing, with emphasis placed on most recent nonfullerene acceptors that demonstrated top-of-the-line photovoltaic performances. We also provide perspectives from a device point of view, wherein topics including ternary blend device, multijunction device, device stability, active layer morphology, and device physics are discussed.