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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.