P3Ht/Pcbm Composite Organic Nanoparticles For Solar Cell Applications: Structure-Function Relationships

Composite organic nanoparticles were fabricated from the conjugated polymer P3HT and the fullerene PCBM. The nanoparticles were studied and implemented in Organic Photovoltaic Devices (OPV) to investigate structure-property relationships and interfacial charge transfer properties of blended functional organic material systems at the molecular- and nanoscale. By learning about the structure-property relationships at the nanoscale we aim to bridge the gap between molecular scale knowledge and experimental observations on macroscopic systems. Our optical data reveal a PCBM concentration dependent formation of two types of P3HT crystalline nanodomains (polymorphs) in P3HT/PCBM composite nanoparticles that show a change in occurrence with changing PCBM doping levels. Device data show heterogeneous kinetics of interfacial charge transfer within nanoparticles. These findings indicate that slight variations in properties and function even at the nanoscale need to be considered in moving towards high efficiency OPV devices