Al₂O₃/TiO₂ double layer anti‐reflection coating film for crystalline silicon solar cells formed by spray pyrolysis

Abstract

An Al 2 O 3 /TiO 2 double layer anti-reflection coating (ARC) film formed by spray pyrolysis was introduced for monocrystalline silicon solar cells as the nonvacuum processing method. The thickness of the Al 2 O 3 layer and TiO 2 compact layer was controlled by the volume of deposited precursor solution and confirmed by ellipsometry and scanning electron microscopy. The average photovoltaic properties of photocurrent density (J sc ), open-circuit photovoltage (V oc ), fill factor (FF), and photo energy conversion efficiency (η) were 37.0 mA/cm 2 , 590 mV, 0.712, and 15.5%, respectively. A significant improvement on J sc and η could be confirmed owing to the Al 2 O 3 /TiO 2 ARC. The results of Fourier transform infrared (FTIR) spectroscopy and optical simulation with modeling for the reflectance properties confirmed that C-H-based organics remained after the deposition of thin films.

Totally Vacuum-Free Processed Crystalline Silicon Solar Cells over 17.5% Conversion Efficiency

“…Although it was shown that the vacuum-less processed TiO 2 , Al 2 O 3 , and ZrO 2 based ARC layers were promising, the power conversion efficiencies were limited to around 16%. The main drawback of those vacuum-less processed solar cells was the insufficient front surface passivation, even though the average reflectance (300-1100 nm) of the textured silicon surface with ARC could be reduced significantly down to below 7% [16][17][18]. In this study, SiO 2 layer formation upon thermal oxidation was performed by O 2 /H 2 O bubbling and a SiO 2 /TiO 2 stack layer was formed with spray deposited TiO 2 film for further improvements.…”

“…In our recent studies, we have been introduced TiO2, Al2O3, and ZrO2 single or double layers based on spin coating or spray pyrolysis methods [16][17][18]. Those results were remarkable to suggest low temperature and non-vacuum processed ARC film as an alternative to mainstream silicon nitrate based films.…”

“…In our previous study [18] [16]. Spray deposited AI 2 O 3 films coated on spray deposited TiO 2 films to finalize <AI/p+/p−Si/n+/TiO 2 /AI 2 O 3 /Ag> structured solar cells either with flat or textured surfaces.…”

“…As an alternative to the vacuum-processed SiN x ARC, TiO 2 and its multilayer structures have been introduced in earlier decades [13][14][15], due to its good optical properties and high refractive index to enhance the light absorption capability of silicon solar cells. In our previous studies, TiO 2 , Al 2 O 3 /TiO 2 , and ZrO 2 /TiO 2 ARC films were introduced [16][17][18] based on spin coating and spray deposition techniques. By adaptation of such simple processing techniques-including spin coating, spray deposition, and screen printing methods-into the cell manufacturing process with proper materials, high efficiency solar cells that can be compatible with their commercial counter parts.…”

Non-Vacuum Process for Production of Crystalline Silicon Solar Cells

“…In depth analysis was carried out with fitting models of "flat layer" as the main body of the coated layer and "rough layer" as the surface residue when depositing a spraydeposited TiO 2 and Al 2 O 3 films [21] and fitted according to the real SEM images. As an optimum value of 60 mL TiO 2 and 100 mL Al 2 O 3 precursor solutions were considered.…”