EP02.05.02 : Novel Infrared Absorbers for Organic Solar Cells

8:30 AM–9:00 AM Apr 4, 2018 (America - Denver)

PCC North, 200 Level, Room 222 BC

Nico Graessler1 Tian-yi Li1 Toni Meyer1 Felix Holzmueller1 Olaf Zeika1 Christian Koerner1 Koen Vandewal1 Karl Leo1

1, IAPP, Dresden, , Germany

Organic solar cells based on vapor-deposited small molecule materials are entering the commercial stage due to their advantages such as combined high efficiency and long lifetime and the possibility to easily realize multijunctions. However, better near infrared absorber materials are needed to cover larger parts of the solar spectrum. In this talk, we will discuss recent developments on two donor materials classes, boron dipyrromethenes (BODIPYS) and merocyanines with a quinoid structure for vacuum-deposited organic solar cells. The materials show high absorption coefficients up to wavelengths of 1100 nm. BODIPYS allow to realize solar cells with – for their wavelength range – comparatively high efficiencies above 6%. The quinoid merocyanines have so far achieved only low efficiencies, but show very unusual photophysical properties, such as an extremely large blue shift of the main absorption peaks of the thin film as compared to the solution, indicating H-aggregation with very large coupling. Morphology investigations with scanning electron microscopy and electron diffraction indicate crystalline growth in nanowires.