(D−π−A)3−Type metal-free organic dye for dye-sensitized solar cells application

Comparing to those of the dye RD−SC bearing a mono D−π−A branch, the dyes PTZTC1−3 containing three independent D−π−A branches exhibit tripled molar extinction coefficient, higher IPCE values and broader IPCE spectra response in the visible region, as well as higher density of D−π−A light-harvesting units absorbed on the surface of TiO2. Among the DSSCs sensitized by these dyes, the cell based on PTZTC3 attained the best power conversion efficiency (PCE) due to the highest short-circuit current, open-circuit voltage and the longest electron lifetime of the device.284