Noncovalent interactions based self-assembled bichromophoric sensitizer for dye-sensitized solar cells

Abstract

A noncovalent interaction based self-assembled ruthenium (II) phthalocyanine (RuPc) and N-pyridyl-peryleneimide (PyPMI) dyad has been exploited to fabricate n-type dye-sensitized solar cells (DSSCs). This supramolecular dyad design is an alternative method to replace the most challenging synthesis of covalent-linked dyads. Metal-coordinated-based dyad complex improved the light-harvesting properties of the photoanodes as opposed to when individual dye anchored on TiO2 surface alone. DSSCs comprise of RuPc⋅PyPMI dyad convert light-to-electrical energy more efficiently (η = 2.29%) than those made of single dye under one sun irradiation (100 mW cm−2) condition. The enhanced photovoltaic performance of the dyad-based devices is due to the broader light absorption of the dyad in the longer wavelengths, enabling better electron injection into the conduction band of TiO2. The combined effect of efficient electron-hole charge separation and the long-lived charge-separated states facilitated the higher short-circuit current density (Jsc) and open-circuit voltage (Voc) of the devices. The enhancement of Voc and Jsc of the devices is confirmed by measuring current–voltage (I–V) curve and incident photon to current conversion efficiency (IPCE) spectrum of each device.