TITLE: Photonic Crystal Geometry for Organic Solar Cells

SPEAKER: Prof. Rene Lopez

TIME: Thursday April 22 at 3 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Two length scales, the absorption depth and carrier transport length, work against one another during the photovoltaic process.  This competition is prevalent over the entire solar spectrum but increasingly so near a semiconductor’s band edge where absorption is weak.  We demonstrate a 2-D, photonic crystal morphology that enhances the efficiency of organic photovoltaic cells relative to conventional planar cells.  The morphology is developed by patterning an organic photoactive bulk heterojunction blend of Poly(3-(2-methyl-2-hexylcarboxylate)thiophene-co-thiophene) and PCBM via PRINTTM, a method that lends itself to large area fabrication of nanostructures. The photonic crystal cell offers the possibility to increase photocurrents generally, and particularly through the excitation of resonant modes near the band edge of organic PV materials.