Precursor of Cs and Pb-oleate: 75 mg of Cs2CO3 (0.46 mmol of Cs + ) and 790 mg of lead acetate trihydrate [Pb(OAc)2.3H2O] (2.0 mmol) are dissolved in 5 mL of oleic acid. The mixture is heated to 100 °C for at least 1 h under reduced pressure to remove water and residual acetic acid from the reaction. The resulting Cs-and Pb-oleate are then used as necessary.