After the preliminary tests with the flat COP platelets were successful, the new coating concept was transferred to the complex hemispherical geometry of the WLE shells. After pre-treatment of oxygen plasma and silica sputtering, they were dip-coated with the TTIP coating solution and subsequently laser-annealed (at 9% laser power) using a scanning program with adjoining concentric rings (see Figs. ). The resulting coating was barely visible to the naked eye (Figure ) but as shown in Figure , the signature Raman signals for anatase TiO2 at 398, 514 and 641 cm -1 were readily observable, similar to the results with the flat platelets. However, a second subsequent coating step let to the formation of rutile (peaks at 434 cm -1 and 609 cm -1 ), whereas under these conditions this