Molecular and Device Engineering of Group 13, 14, 15 Phthalocyanines and Tetrabenzotriazacorroles for Organic Photovoltaic Applications

Phthalocyanines (Pcs) are a family of compounds that constitute a key building block of the organic photovoltaic (OPV) literature. Aside from their desirable optical and electronic properties, we are interested in Pcs because of their proven scalability and stability, unlike most organic semiconductors in literature. Although the Pc chromophores can chelate to almost all elements of the periodic table and conform to varying molecular structures, research in the context of OPVs has been largely concentrated on planar derivatives that chelate to metal centres without axial substituents. This render them molecularly unmodifiable hindering the understanding of structure-property-performance relationships of Pcs in the context of OPVs. In this dissertation, axially-bonding Pc compounds incorporating elements from groups 13, 14, and 15 into their cavities were engineered chemically by axial phenoxylation and by ring-contraction chemistry into tetrabenzotriazacorroles (Tbcs). The functionality of the modified molecules was also assessed in OPVs. Aluminum, silicon, and phosphorus were selected to represent tri-, tetra-, and penta- valent elements respectively. Series of axially-phenoxylated aluminum phthalocyanines (AlPcs) and silicon phthalocyanines (SiPcs) were synthesized, characterized, and incorporated into OPV devices. These easily prepared derivatives exhibited superior OPV performances in comparison to their baselines as electron acceptors. Tbcs which differ structurally from Pcs with the omission of a single imine nitrogen were unknown in the context of OPVs. This small difference in structure has paramount effects on the optical and electrochemical properties of the chromophore. For example, Tbcs exhibit a unique and desirable dual absorption of blue and red portions of the solar spectrum simultaneously. The first application of any Tbc compound in OPVs, oxy phosphorus tetrabenzotriazacorrole (POTbc) as a prototype, paired with conventional organic semiconductors is reported here. POTbc showed promise as an electron donating material due to its highly charged chromophore. POTbc was then coupled with boron subphthalocyanines (BsubPcs) as complementary absorbing donor-acceptor pairs in fullerene-free “black” OPVs. The outdoor stability of POTbc/BsubPc devices were assessed exhibiting on-par stability with their baseline. Further molecular structures of Tbcs, and resulting properties, were enabled through the synthesis of multiple Tbc derivatives chelating to a silicon center (SiTbcs).Ph.D.2019-07-11 00:00:0