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Effect of Ultraviolet Radiation on Organic Photovoltaic Materials and Devices

Patel, Jay B., Tiwana, Priti, Seidler, Nico, Morse, Graham E., Lozman, Owen R., Johnston, Michael B., Herz, Laura M.
ACS applied materials & interfaces 2019 v.11 no.24 pp. 21543-21551
air, buildings, carbon, cities, cost effectiveness, electric current, electric vehicles, encapsulation, filters, microstructure, photolysis, photons, photovoltaic cells, power generation, semiconductors, solar energy, solar radiation, ultraviolet radiation, zero emissions
Organic photovoltaics are a sustainable and cost-effective power-generation technology that may aid the move to zero-emission buildings, carbon neutral cities, and electric vehicles. While state-of-the-art organic photovoltaic devices can be encapsulated to withstand air and moisture, they are currently still susceptible to light-induced degradation, leading to a decline in the long-term efficiency of the devices. In this study, the role of ultraviolet (UV) radiation on a multilayer organic photovoltaic device is systematically uncovered using spectral filtering. By applying long-pass filters to remove different parts of the UV portion of the AM1.5G spectrum, two main photodegradation processes are shown to occur in the organic photovoltaic devices. A UV-activated process is found to cause a significant decrease in the photocurrent across the whole spectrum and is most likely linked to the deterioration of the charge extraction layers. In addition, a photodegradation process caused by UV-filtered sunlight is found to change the micromorphology of the bulk heterojunction material, leading to a reduction in photocurrent at high photon energies. These findings strongly suggest that the fabrication of inherently photostable organic photovoltaic devices will require the replacement of fullerene-based electron transporter materials with alternative organic semiconductors.