Hysteresis-less mesoscopic CH3NH3PbI3 perovskite hybrid solar cells by introduction of Li-treated TiO2 electrode

• Hysteresis-free mesoscopic perovskite solar cell by introduction of Li-treated mesoscopic TiO2 electrode.
• Improved charge injection and transport by Li-treatment of mesoscopic TiO2

A great current density–voltage (J–V) hysteresis with respect to the scan direction is important issue in perovskite hybrid solar cells because the power conversion efficiency is sometimes incorrect. Here, we demonstrated >17% mesoscopic CH3NH3PbI3 (MAPbI3) perovskite hybride solar cells without significant J–V hysteresis with respective to the scan direction and rated by using Li-treated mesoscopic TiO2 electrode. The Li-treated mesoscopic TiO2 electrode improved charge separation/injection from MAPbI3 into mesoscopic TiO2, charge transport in mesoscopic TiO2, and surface traps because the conduction band edge of mesoscopic TiO2 was lowered by ~0.1 eV, the mobility of charge carriers was increased from ~1.1×10−6 cm2/V s to ~2.5×10−6 cm2/V s, the conductivity of mesoscopic TiO2 was increased from ~5.6×10−7 S/cm to ~1.6×10−6 S/cm, and the trap density was reduced from ~1.2×1016 cm−3 to ~9.3×1015 cm−3 through Li-treatment. Therefore, the average power conversion efficiency was significantly enhanced from 14.84% to 17.26% at 1 sun condition by the Li-treatment of mesoscopic TiO2.

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