Atomically Designed Graphene Nanoribbons for Photovoltaic Applications

Graphene nanoribbons (GNRs) were considered important for solar applications due to their exceptional electrical conductivity, high light absorption, and unique edge properties which can facilitate efficient charge carrier separation, making them promising candidates for use in solar cells as electrodes, interfacial layers, or even active materials in certain designs. These nanoribbons can be good alternatives as carrier extraction interlayers for organic/inorganic hybrid solar cells, through varying the width and the type of edge functionalization. GNRs were synthesized from two different organic molecules and were utilized to prepare thin films of nanocomposites with ZnO and TiO₂ nanoparticles to study their current-voltage properties. The designing was carried out in such a way that both aromatic organic molecules, namely, o-amino phenol and p-amino benzoic acid, when treated to cracking at very low temperatures, resulted in the production of nanoribbons like pattern. The band gap energy of GNRs obtained from both molecules was calculated, which indicated their semiconducting property suitable for photo-voltaic applications. The AFM images of the nanocomposites clearly showed the uniform distribution of the metal oxide nanoparticles on the surface of the GNRs. The current–voltage (I–V) properties of the nanocomposites were investigated and open-circuit photovoltage (V_OC), short-circuit photocurrent (I_SC), fill factor (FF) along with power conversion efficiency (PCE) of the solar cell were measured. Interestingly, the nanocomposites of GNRs prepared from the organic compounds p-amino benzoic acid showed a higher PCE value (2.069%).