One-step preparation of TiO2 anti-reflection coating and cover layer by liquid phase deposition for monocrystalline Si PERC solar cell

Abstract

This study proposed a one-step liquid phase deposition (LPD) technique to fabricate a front-side anti-reflective coating (ARC) and rear-side cover layer for a passivated emitter and rear cell solar cell. The production process involves the deposition of TiO 2 thin film by using a (NH 4 ) 2 TiF 6 and H 3 BO 3 mixture in a liquid phase filter and cycling deposition system, in which H 3 BO 3 concentration influences the TiO 2 thin film deposition rate, the Ti x Si 1-x O y interfacial layer thickness, and thin film quality. The proposed technique is a one-step, uniform, and large-scale double-sided coating batch process viable for non-vacuum environments, thus enabling a simple manufacturing process and requiring low equipment costs. The fabricated LPD-TiO 2 thin film demonstrated ASTM 5B adhesion and 3.3% uniformity. The technique involves the use of a 0.2 M (NH 4 ) 2 TiF 6 and 0.5 M H 3 BO 3 mixture for deposition under 50 °C to deposit a 68-nm-thick LPD-TiO 2 thin film on pyramid Si wafer. The average reflectance and transmittance of the thin film at 400–800 nm wavelength was 2.7% and 96.5%, respectively. Passivated emitter and rear contact solar cells prepared using the proposed LPD-TiO 2 coating technique demonstrated the following outstanding properties: 9.8 A short-circuit current, 0.68 V open circuit voltage, 81.0% fill factor, and 21.3% photoelectric conversion efficiency (η). The proposed technique demonstrates high potential for use in the low-cost manufacturing of silicon solar cells. • Passivated emitter and rear contact (PERC) solar cells are fabricated. • Front-side anti-reflective and back-side cover layers are prepared in one step. • Low cost and batch-type of TiO 2 films are made by liquid phase deposition (LPD). • PERC solar cell with the LPD functional films shows the better characteristics. • LPD-TiO 2 functional films are favorable for high performance PERC solar cells.