|Organization or Institution||University of Florida|
DESIGN AND SYNTHESIS OF PHTHALHYDRAZIDE-DIRECTED SELF-ASSEMBLING π-CONJUGATED OLIGOMERS FOR ORGANIC PHOTOVOLTAICS (OPVs)
Lei Li,1 Xiaoyang Yan,1 Cheng-Yen Pan,1 and Ronald K. Castellano1
1 Department of Chemistry,University of Florida, P.O. Box 117200, Gainesville, FL 32611
Photovoltaic active layers composed of organic semiconductive small molecules remain promising platforms to achieve affordable solar energy conversion. Despite their benefits, organic photovoltaic devices based on the bulk heterojunction structure still suffer from relatively low power conversion efficiency due to the random and poorly controllable bulk morphology and low stability, which gradually deteriorates their performance. To address these challenges, we envision a hierarchical supramolecular approach, in which modularly constructed π-conjugated electron donor oligomers are equipped with hydrogen-bonding (phthalhydrazide) domain to guide chromophore self-assembly and secure more optimal pathways for charge generation and transport. We designed oligomers that feature a linear acceptor-donor (A-D) structure to maintain a narrow HOMO-LUMO energy gap, aromatic hydrogen-bonding units at the terminus to induce 2-D network formation, and planar construction to encourage organization via π-π stacking interaction. Ultimately, the programmed molecular-scale order will be correlated to bulk material properties and photovoltaic functionality.