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

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 TiO 2 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 TiO 2 . 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. Graphical abstract Fabrication and operational principles of self-assembled PyPMI--RuPc dyad based DSSCs