Solution-Processed Hybrid Cathode Interlayer for Inverted Organic Solar Cells

A novel hybrid material CdS/2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline
(CdS·BCP) was prepared from the decomposition of its organic
soluble precursor complex Cd­(S2COEt)2·(BCP)
by low-temperature treatment. CdS·BCP, which integrated the favorable
properties of solvent durability, and high electron mobility of CdS
as well as the good hole blocking property of BCP, was designed and
developed as the interface modification material to improve electron
collection in bulk heterojunction organic solar cells (OSCs). The
inverted OSCs with CdS·BCP as buffer layer on ITO showed improved
efficiency compared with the pure CdS or BCP. Devices with CdS·BCP
as interlayer exhibited excellent stability, only 14.19% decay of
power conversion efficiencies (PCEs) was observed (from 7.47% to 6.41%)
after stored in glovebox for 3264 h (136 days). Our results demonstrate
promising potentials of hybrid materials as the interface modification
layers in OSCs, and provide new insights for the development of new
interface modification materials in the future.