AUTHOR=Di Sabatino Marisa , Ceccaroli Bruno TITLE=Editorial: Upgraded metallurgical grade silicon: quality, applications, and process economics JOURNAL=Frontiers in Photonics VOLUME=6 YEAR=2025 URL=https://www.frontiersin.org/journals/photonics/articles/10.3389/fphot.2025.1544237 DOI=10.3389/fphot.2025.1544237 ISSN=2673-6853