Quantification of impurities in diatomite via sensitivity-improved calibration-free laser-induced breakdown spectroscopy

The detection of impurities in diatomite is a critical issue during the silicon extraction process. Impurities can significantly impact the properties of silicon, compromising the performance of Si solar cells. In the present work, we applied a sensitivity-improved calibration-free LIBS measurement approach to assess the quality of diatomite. Based on the recording of two spectra with different delays between the laser pulse and the detector gate, the method enables the quantification of major, minor, and trace elements. The limits of detection for minor and trace elements were evaluated. Furthermore, we investigated the morphology and properties of the diatomite surface using Energy-Dispersive X-ray Spectroscopy and Scanning Electron Microscopy analysis. This research contributes to process optimization in the fabrication of electronic grade silicon from diatomite for photovoltaic technology and other applications.