writer：Yansong Ge, Xinyu Xiao, Ge Yao, Shuaishuai Yuan,* Lin Zhang,* Weihua Zhou*
keywords：polyvinylidene fluoride, poly(styrene-comethyl-methacrylate), dual interface protection, stability, organic solar cells
source：期刊
specific source：ACS Applied Materials & Interfaces
Issue time：2021年

Stability is still the main barrier to the commercial application of

organic solar cells (OSCs), although the maximal power conversion efficiency (PCE)

value has exceeded 19%. The encapsulation technique is an effective and vital way to

guarantee the long-term stabilities of OSCs, but it can only avoid the penetration of

water and oxygen from the environment. Herein, we introduced a structure that

provides dual interface protection by using commercially available and chemically

stable polyvinylidene fluoride (PVDF) as the cathode interface protection layer

working as the cathode interlayer (CIL) and poly(styrene-comethyl-methacrylate)

(PS-r-PMMA) as the anode interface protection layer between the poly(3,4-

ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) and the active

layer. With this structure, both the migration of impurities caused by degradation of

the interfacial layer and the infiltration of oxygen and water in the air can be

prevented. PVDF can effectively provide optimal electron transfer by improving the

surface potential of active layers and lowering the work function of the Al electrode.

PS-r-PMMA can improve the hydrophobicity of PEDOT:PSS and induce optimized phase separation, facilitating charge transfer.

After storage in an air environment with a humidity of approximately 60% for 3600 h, the device based on the PM6:IT-4F blend film

with dual interface protection showed a decrease in its PCE value from 13.43 to 10.90%, retaining 81.2% of its original PCE value, in

contrast to the sharp decrease in the PCE value from 13.66 to 0.74% of the device without dual interface protection. The dual

interface protection design could also be useful in the high-performance PM6:Y6 system, which shows a champion PCE of 15.39%

and shows potential for the effective fabrication of stable OSCs in the future