1 research outputs found
Interfacial Engineering with Cross-Linkable Fullerene Derivatives for High-Performance Perovskite Solar Cells
Two fullerene derivatives
with styryl and oxetane cross-linking
groups served as interfacial materials to modify an electron-transporting
layer (ETL) of TiO<sub>2</sub>, doped with Au nanoparticles, processed
under low-temperature conditions to improve the performance of perovskite
solar cells (PSC). The cross-linkable [6,6]-phenyl-C<sub>61</sub>-butyric
styryl dendron ester was produced via thermal treatment at 160 °C
for 20 min, whereas the cross-linkable [6,6]-phenyl-C<sub>61</sub>-butyric oxetane dendron ester (C-PCBOD) was obtained via UV-curing
treatment for 45 s. Both cross-linked fullerenes can passivate surface-trap
states of TiO<sub>2</sub> and have also excellent surface coverage
on the TiO<sub>2</sub> layer shown in the corresponding atomic force
microscopy images. To improve the crystallinity of perovskite, we
propose a simple co-solvent method involving mixing dimethylformamide
(DMF) and dimethyl sulfoxide (DMSO) in a specific ratio (DMF/DMSO
= 90/10). The fullerene derivative layer between the ETL and perovskite
layers significantly improved electron extraction and suppressed charge
recombination by decreasing the density of traps at the ETL surface.
A planar PSC device was fabricated with the configuration indium tin
oxide/TiO<sub>2</sub> (Au)/C-PCBOD/perovskite/spiro-OMeTAD/Au to attain
a power conversion efficiency (PCE) of 15.9%. The device performance
was optimized with C-PCBOD as an interfacial mediate to modify the
surface of the mesoporous TiO<sub>2</sub> ETL; the C-PCBOD-treated
device attained a significantly enhanced performance, PCE 18.3%. Electrochemical
impedance spectral and photoluminescence decay measurements were carried
out to understand the characteristics of electron transfer and charge
recombination of the perovskite/TiO<sub>2</sub> samples with and without
a fullerene interfacial layer