Organic solar cells based on a novel infrared absorbing aza-bodipy dye

Journal article

For high efficiencies, organic solar cells have to harvest a large part of the solar spectrum. However, in particular for small molecule based cells, efficient infrared absorbers are still rare. We investigate here two aza-bodipy dyes which have promising properties. Upon benzannulation of the pyrrole of difluoro-bora-1,3,5,7-tetraphenyl-aza-dipyrromethene (Ph₄-bodipy), the thin film absorption maximum is shifted by about 70–773 nm compared to the non-annulated molecule. The thin film properties of both materials are investigated and vacuum-processed solar cells using a mip-architecture (metal intrinsic p-doped) are compared. With the new benzannulated difluoro-bora-bis- (1-phenyl-indoyl)-azamethine (Ph₂-benz-bodipy) as donor material, these planar heterojunction solar cells show an open-circuit voltage of 0.65 V, a fill factor of 65%, and an external quantum efficiency extending up to 860 nm. The mismatch corrected power conversion efficiency reaches 1.1%.

Authors: Mueller, T; Gresser, R; Leo, K; Riede, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Solar Energy Materials and Solar Cells
• Volume: 99
• Pages: 176-181
• Publication date: 2012-04-01
• DOI: 10.1016/j.solmat.2011.11.006
• ISSN: 0927-0248
• Language: English
• Keywords: Mismatch correction; Small molecule; Heterojunction; Infrared; Organic