1 research outputs found
Solution-Processed Bulk-Heterojunction Solar Cells containing Self-Organized Disk-Shaped Donors
Two molecular disks <b>1</b> and <b>2</b> composed
of a central pyrene core, four oligothiopenes, and peripheral alkyl
chains were synthesized and characterized with respect to optical
and redox properties in solution and in solid films. It was found
that the lowest unoccupied molecular orbital (LUMO) energy levels
of <b>1</b> and <b>2</b> were ideal for achieving efficient
electron transfer to fullerene derivatives PC<sub>60</sub>BM and PC<sub>70</sub>BM, and that <b>1</b> and <b>2</b> can function
as electron donor components in solution-processed bulk-heterojunction
(BHJ) solar cells. Disk-shaped molecules <b>1</b> and <b>2</b> organized ordered structures through intermolecular ΟβΟ
interactions as monitored by temperature-controlled polarized optical
microscope (TPOM), differential scanning calorimetry (DSC), and powder
X-ray diffraction (XRD). Solution-processed BHJ solar cells using <b>1</b> or <b>2</b> as electron donor materials and fullerene
derivatives as acceptor materials were fabricated and investigated.
The oligothiophene lengths were reflected in the performance characteristics
of solar cell devices fabricated using disk-shaped donors <b>1</b> and <b>2</b>. Power conversion efficiency (PCE) of 2.6% was
achieved for small-molecule BHJ solar cells containing self-organized
crystals of <b>2</b> in the active layer under one sun condition