Effects of Ti precursors on the performance of planar perovskite solar cells

Abstract

Perovskite solar cells (PSCs) have attracted enormous attention because of their superior photovoltaic conversion efficiency and low-cost solution processibility. Electron transport layer (ETL) is essential to the performance of PSCs due to its ability of transporting electrons and blocking holes. Herein, the effect of different Ti precursors, tetrabutyl titanate (TT) and titanium diisopropoxide bis (acetylacetonate) (TDB), on the properties of derived TiO2 ETL was systematically investigated. It is noted that the change of Ti precursor have significant influence on the surface state and morphology, electron extraction ability and interface recombination resistance, but not on the crystal phases and chemical states of the obtained TiO2 ETLs. Moreover, compared with TiO2 ETL derived from TDB, the one obtained from TT displays the superior photoelectric properties and the PSCs based on this ETL acquire the best power conversion efficiency (PCE) of 17.4% with an open-circuit voltage (Voc) of 1.1 V, a short-circuit current density (Jsc) of 23.2 mA cm−2 and a fill factor (FF) of 68%. We believe that some fundamental insight into the impact of Ti precursor was provided in this research, aiming to find the criterion of the qualified ETL and paving the route for fabricating desirable ETL.