Efficient planar perovskite solar cells with low-temperature atomic layer deposited TiO2 electron transport layer and interfacial modifier

Perovskite solar cells (PSCs) have attracted increasing attentions for their outstanding efficiency and simple fabrication process. However, the commonly used typical titanium dioxide (TiO2) electron transport layer (ETL) requires a high-temperature treatment to crystallize. In this work, the low-temperature (150 °C) atomic layer deposition (ALD) processed TiO2 ETL, and the SnO2/PCBM double interfacial modifier have been adopted to fabricate the high performance PSCs of ITO/ALD-TiO2/SnO2/PC61BM/MA0.7FA0.3PbI(3-x)Cl(x)/Spiro-OMeTAD/Ag. The measurement results show that the PSCs with ALD-TiO2 ETL obtain the higher champion PCE of 19.45% than that of PSC with solution-TiO2 ETLs (PCE = 18.64%), along with the obviously enhanced FF and VOC, as well as the better light stability and repeatability. And the transient photocurrent and photovoltage results demonstrate that the performance improvement origins from the enhanced charge transport and suppressed charge recombination. Therefore, the low-temperature ALD-TiO2 ETL with suitable modification is a promising strategy to fabricate efficient PSCs and flexible devices.