SiNPs Decoration of Silicon Solar Cells and Size Analysis on the Downshifting Mechanism Response for the Enhancement of Solar Cells Efficiency

In this work, we present experimental and theoretical analysis of the absorbance of the SiNPs that exhibit an interesting behavior on light manipulation through the downshifting mechanism. Silicon nanoparticles (1 nm <radius < 3 nm) were synthesized using a green chemistry method, and characterized to determine its experimental absorbance region, size, crystallographic structure, and luminescence response. To evaluate the theoretical absorbance performance of SiNPs (radius < 3 nm), Mie’s theory was used to explore different scenarios considering: an isolated single silicon NP, an array of SiNPs with a specific size distribution and Si-SiO2 core-shell NPs. Also, a simple model to analyze the luminescence and their effect using a size distribution on the emission spectra are examined. Finally, the efficiency enhancement of Si solar cells using SiNPs as a downshifting material was explored. The presence of the nanoparticles on the device’s surface was revealed by scanning electron microscopy. The solar cell’s parameters, current-voltage characteristics, power-voltage curves were obtained. A current density of 24.2 mA/cm2, open-circuit voltage of 610 mV and a fill factor of 72% and an overall power conversion efficiency of 45% are reported. These results show that the controlled dosing of SiNPs in aqueous solution has a high potential to be applied as an antireflective coating complement to improve the efficiency of large-scale solar cells due to the simplicity of the method, low toxicity and easy distribution over large areas.