Hot sulfuric acid can be used as etchant for a TiO2 layer covering a conventional glass substrate, and seemingly could provide enough selectivity while considering its substitution by a fluorine-doped tin oxide (FTO) coated glass slide (FTO-glass). However, because the information available on the (possible) FTO-glass corrosion by H2SO4 is rather limited, it would be necessary to perform experimental essays, to check if the (supposed) selectivity could be sufficient in the actual practice, and being that the case, to optimize the experimental protocol.
Sulfuric acid would corrode aluminum, indeed. Taking that into account, I would suggest aq. solution of NH4OH + H2O2 (1:2). For details you may refer to: J.-P. Rioult, R. Fabien (Assignee: U.S. Philips Corporation); “Method for selective etching of titanium dioxide relative to aluminum”, U.S. Patent 4,322,264; Mar. 30, 1982.
I completely agree with Dr. Shen, his mentioned the ideal method. Also, its easily use the mixture of solvents from DMF and ethanol in dipping the glass in sonication bath more than five hour and later cleaned in deionized water and then dried in N2 gas.
The most suitable method to remove layers without damaging the other adjacent layers is by means of selective wet chemical etching. So, please search for selective etching solutions to the perovskite compound and for TiO2 without etching ITO of FTO.