Modification of ITO Surface by Phenyl Boronic Acid Self-Assembled Monolayers for Organic Solar Cell Application: An Experimental and DFT Investigation

Currently, interfacial modification of organic solar cells (OSCs) is one of the most effective strategies for improved performance. Self-assembled monolayers (SAMs) stand out to modulate the electrical and morphological properties of indium tin oxide (ITO). Here, we studied the properties of 4-(9H-carbazol-9-yl)phenyl boronic acid (BA-4,9-C) and 4-(diphenylamino)phenyl boronic acid (BA-4-DA) theoretically through density-functional theory (DFT) and utilized them as novel SAMs to modify ITO surfaces in OSCs. We report that the integration of both BA-4,9-C and BA-4-DA into the device structure can promote the increasing of the work function of ITO and better coating of upper layers, resulting in an enhancement of the photovoltaic parameters. The power conversion efficiencies (PCEs) of BA-4,9-C and BA-4-DA modified devices show approximately 21% and 50% improvements, respectively. These improvements can contribute to the providing of highly efficient bulk hetero-junction OSCs.