If you are coating the TiO2 on the glass without using a thickener or ligand to make the TiO2 porous you simply have the cristal structure of your TiO2 (for example with rutile). The structure you can look up by googling it. (If the structure is really not porous you can simply use more dye because it only adsorpes at the surface, but to be really sure that you only have one layer and to provide from dimerization between dye molecules - which could be because of the attractive forces between the bonding and antibonding pi-orbitals of several dyes, it's better to calculate the exact quantity needed.)

Now it's important which dye you are using. Watching the cristal structure you can although look up the bonding between your dye and the TiO2. If using phosphonated dyes for example you simply have one molecule per TiO2. Phosphonic bonding is incidentally useful because this chemically adsorption is irreversible even in aqueous Too be sure how your die adsorbed at the TiO2 you can although download a chemical draw program such as chemdraw. When you create the molecules there you got a warning if your construction is wrong.

So at last you simply have to calculate the molecular mass into the mass in g you are using and calculate with the rule of three and so you have the right quantity you need.  Hope it works.

Hi Doro

thanks for the reply. i do sinter the TiO2 film with FTO at 500oC and then cool for sensitising. 

Yes. i need to workout the quantity of dye for the mono-layer sensitisation.

Regards

Hi

You can also try the Lagmuir deposition techiques: Langmuir-Schaefer and Langmuir-Blodgett. You can trasfer monomolecular layer of chosen dye from air watter interface. You also have very good cotrol of  area per molecule. See below links:

https://en.wikipedia.org/wiki/Langmuir%E2%80%93Blodgett_film

http://www.biolinscientific.com/zafepress.php?url=%2Fpdf%2FKSV%20NIMA%2FTheory%20Notes%2FKN_TN_2_what-and-why-langmuir-blodgett-films.pdf