Improved Self-cleaning Properties of an Efficient and Easy to Scale up TiO2 Thin Films Prepared by Adsorptive Self-Assembly

TL;DR

This study presents a scalable method to produce TiO2 thin films with enhanced self-cleaning and anti-reflection properties, significantly reducing dust accumulation and improving transparency for photovoltaic applications.

Contribution

The paper introduces an efficient adsorptive self-assembly process to create TiO2 nanofilm coatings with improved self-cleaning and anti-reflective features, suitable for large-scale deployment.

Findings

56% reduction in dust deposition after 7 days

Less than 6% transmission loss compared to bare glass

Films exhibit high anti-reflection properties

Abstract

Transparent titania coatings have self-cleaning and anti-reflection properties (AR) that are of great importance to minimize soiling effect on photovoltaic modules. In this work, TiO2 nanocolloids prepared by polyol reduction method were successfully used as coating thin films onto borosilicate glass substrates via adsorptive self-assembly process. The nanocolloids were characterized by transmission electron microscopy and x-ray diffraction. The average particle size was around 2.6 nm. The films which have an average thickness of 76.2 nm and refractive index of 1.51 showed distinctive anti soiling properties under desert environment. The film surface topography, uniformity, wettability, thickness and refractive index were characterized using x-ray diffraction, atomic force microscopy, scanning electron microscopy, water contact angle measurements and ellipsometry. The self-cleaning properties were investigated by optical microscopy and UV-Vis spectroscopy. The optical images show 56% reduction of dust deposition rate over the coated surfaces compared with bare glass substrates after 7 days of soiling. The transmission optical spectra of these films collected at normal incidence angle show high anti-reflection properties with the coated substrates having transmission loss of less than 6% compared to bare clean glass.