Novel D-D-π-A indoline-linked coumarin sensitizers for dye-sensitized solar cells

Abstract

Two indoline-linked coumarin double donor sensitizing dyes were synthesized with thiophene as π-bridge and cyanoacrylic acid as acceptor. Two sensitizing dyes differ mainly in the bonding mode of double donors: indoline linked with coumarin through CN bond or CC bond. The incorporation of indoline unit improves the antiaggregation ability and inhibits the charge recombination. Compared with their counterpart bearing diethylaminocoumarin donor, indoline-linked coumarin sensitizing dyes exhibit improved VOC of ˜ 700 mV from the previous 570 mV and accordingly better photoelectric conversion efficiency. However, the bonding mode of double donors leads to different JSC. Dye in which indoline linked with coumarin through CC bond shows better IPCE and accordingly higher JSC, which contributes to its superior photovoltaic performance.