Planar perovskite solar cells with La$_2$NiMnO$_6$ buffer layer

Thin films of La$_2$NiMnO$_6$ (LNMO) double perovskite oxide were first used as buffer layers in planar perovskite solar cells (PSCs) with the architecture of glass/FTO/LNMO/CH$_3$NH$_3$PbI$_3$/Spiro-MeOTAD/Au. All PSCs were fabricated under ambient conditions and their photovoltaic parameters were measured under standard illumination (AM1.5G, 1000 W/m$^2$). Power conversion efficiency (PCE) values (10 – 11%) for the PSCs developed were comparable with those obtained for conventional PSCs with compact TiO$_2$ (cTiO$_2$) layer, but the stability of PSCs with LNMO buffer layer was significantly higher than for cTiO$_2$-based PSCs.