High-performance Al2O3 sol-gel films: Improving solar cell efficiency through antireflective and superhydrophobic properties

Author(s)

Carvalho, Ramon Dadalto ; Fernandes, Cristian Dias ; Pereira, Marcelo Barbalho ; Alves, Samantha Cardoso ; Jardim, Pedro Lovato Gomes ; Cava, Sergio da Silva ; Ferrer, Mateus Meneghetti ; Raubach, Cristiane Wienke ; Longo, Elson ; Moreira, Mario Lucio

• Document type: Journal article
• Source: Applied Surface Science; v. 702, p. 9-pg., 2025-09-01.

Abstract

This study developed a multifunctional aluminum oxide (Al2O3) film combining anti-reflective and super-hydrophobic properties for enhanced photovoltaic (PV) performance in outdoor applications. The film was created on glass substrates using a sol-gel, dip coating, and controlled etching process, resulting in a porous surface with grass-like nanostructures. After 512 s of etching, the film achieved a roughness of 23.63 nm and a refractive index of 1.14 at 550 nm. It demonstrated excellent broadband anti-reflection, with 96.86% average transmittance and 3.07% reflectance across the 350-1500 nm spectrum, peaking at 99.30% transmittance at 480 nm. The film maintained over 90% transmittance at angles up to 45 degrees, providing omnidirectional functionality crucial for solar panels. Its superhydrophobicity (162.3 degrees water contact angle and hysteresis 7.5 degrees) ensures self-cleaning. When applied as a solar cell cover glass coating, the film enhanced short-circuit current density and power conversion efficiency. A 19.19% efficiency increase was observed at a 60 degrees incidence angle, demonstrating the film's potential for significant PV performance improvement. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 24/10185-2 - Development and application of anti-reflective and self-cleaning films to increase solar cell efficiency.
• Grantee: Ramon Dadalto Carvalho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral