The structural, optical and morphological properties of the tantalum pentoxide (Ta2O5) and SiO2/Ta2O5 films to be used as an anti-reflective coating (ARC) were investigated. Besides, it was examined and discussed in detail how the performance of MBE grown GaInP/GaAs/Ge triple-junction solar cell (TJSC) structure was affected by the single and double-layer ARCs. The SIMS results showed that uniform atomic distribution has formed throughout the depth of the deposited films. The XPS analysis results demonstrated that the chemical structures of the films were Ta2O5 and SiO2. The FTIR absorbance spectra confirmed that the compositions of the films were Ta2O5 and SiO2/Ta2O5. It was determined that the average optical reflectivity values were decreased to 14% and 7% with the use of Ta2O5 and SiO2/Ta2O5, respectively. The SLARC and DLARC have increased the conversion efficiency of the fabricated TJSCs by around 6% and 19%. The ARCs caused an increase in the EQE and J(sc) values of each sub-cell. The obtained results clearly demonstrated that the enhanced anti-reflective performance corresponding to decreasing optical reflection losses with the SiO2/Ta2O5 DLARC had improved the electrical performance better compared to the Ta2O5 SLARC. (C) 2019 Elsevier B.V. All rights reserved.