1：Experimental Design and Method Selection

The study employed a hydrothermal method for the deposition of TiO2 thin films, chosen for its simplicity, low cost, and low operational temperature. The effect of deposition time on the properties of the films was investigated.

2：Sample Selection and Data Sources

Titanium isopropoxide (TTIP) was used as the precursor for TiO2 thin films. The films were deposited on cleaned substrates at various deposition times (3 h, 4 h, 5 h, and 6 h).

3：List of Experimental Equipment and Materials

Bruker D2 phaser diffractometer for XRD, Shimadzu UV–Vis-1800 spectrophotometer for optical properties, FESEM (Mira3; TESCAN) for morphological study, EDAX (Oxford Instruments) for elemental analysis, and an electrochemical analyzer for UV sensing properties.

4：Experimental Procedures and Operational Workflow

The TiO2 thin films were deposited by dissolving TTIP in double-distilled water and concentrated HCl, stirring the mixture, and transferring it to a Teflon flask. The substrates were immersed in the solution and kept at 160°C for various deposition times. The films were then annealed at 450°C for 5 h.

5：Data Analysis Methods

The crystallite size was calculated using the Debye–Scherrer formula. The optical band gap energy was determined from absorption spectra and Tauc plots. The photoresponse and responsivity of the photodetector were measured under UV illumination.