An amount of 100 mg of zinc acetate
dihydrate was dispersed into 100 mL of DMF using sonication and vortex
mixing processes. The clear solution was then sustained at 105 °C
for 5 h. The FTO glass substrate (received from Sigma-Aldrich; surface
resistivity ≈ 7 Ω sq.–1) was cleaned
with isopropyl alcohol, ethanol, and deionized (DI) water followed
by UV ozone treatment for 20 min. The ZnO NPs seed layer was prepared
on an FTO glass substrate via spin-coating (1000 rpm, 1 min) and dried
at 150 °C for 5 min. The process was repeated five times to obtain
a uniform ZnO NPs seed layer, which was then thermally treated at
250 °C for 1 h in air.
dihydrate was dispersed into 100 mL of DMF using sonication and vortex
mixing processes. The clear solution was then sustained at 105 °C
for 5 h. The FTO glass substrate (received from Sigma-Aldrich; surface
resistivity ≈ 7 Ω sq.–1) was cleaned
with isopropyl alcohol, ethanol, and deionized (DI) water followed
by UV ozone treatment for 20 min. The ZnO NPs seed layer was prepared
on an FTO glass substrate via spin-coating (1000 rpm, 1 min) and dried
at 150 °C for 5 min. The process was repeated five times to obtain
a uniform ZnO NPs seed layer, which was then thermally treated at
250 °C for 1 h in air.