Beyond the Threshold: A Study of Chalcogenophene-Based Two-Photon Initiators. - Lunzer M; Beckwith JS; Chalupa-Gantner F; Rosspeintner A; Licari G; Steiger W; Hametner C; Liska R; Fröhlich J; Vauthey E; Ovsianikov A; Holzer B (Chemistry of materials : a publication of the American Chemical Society, 2022)