Suppressing Charge Recombination and Ultraviolet Light Degradation of Perovskite Solar Cells Using Silicon Oxide Passivation

Graphical Light it up : Retarding charge recombination and ultraviolet light irradiation degradation of lead-halide perovskite solar cells is highly desirable for their large-scale application. This work demonstrates that a SiO x interfacial layer inserted between the electron transporting layer and light-absorber layer passivates the trap states of lead-halide perovskite and simultaneously suppresses the charge recombination, resulting in an 18 % efficiency output of TiO 2 -based planar perovskite solar cells and improved light soaking stability under ultraviolet light irradiation. Organic-metal lead halide perovskite solar cells (PSCs) featuring low-cost and high efficiency have been recognized as promising photovoltaic devices, but their serious charge recombination and ultraviolet light irradiation instability limit their output efficiency and long-term operation. In this work, we have introduced silicon oxide as an interfacial modifier of the electron transporting layer in TiO 2 -based planar heterojunction PSCs. The incorporation of a silicon oxide modifier passivates the trap states of perovskite absorber and suppresses the charge recombination of PSCs. As a consequence, a competitive solar-to-electricity conversion efficiency of 18.0 % was achieved for the device fabricated with the silicon-oxide-modified TiO 2 electron extraction layer, which is increased by 15 % compared with the PSC fabricated with pristine TiO 2 ; this can be attributed to the significantly increased open-circuit voltage and photocurrent density. Furthermore, the ultraviolet light irradiation stability of PSCs is greatly improved, resulting from the low photocatalytic activity of the silicon-oxide-modified TiO 2 electron transporting layer, as revealed by the photoelectrochemical oxidation of CH 3 NH 2 . This work represents a feasible step through interfacial engineering toward the realization of ultraviolet-light-stable and scalable PSCs.