Authors: Danila Quarta, Stefano Toso, Roberto Giannuzzi, Rocco Caliandro, Anna Moliterni, Gabriele Saleh, Agostina-Lina Capodilupo, Doriana Debellis, Mirko Prato, Concetta Nobile, Vincenzo Maiorano, Ivan Infante, Giuseppe Gigli, Cinzia Giannini, Liberato Manna, and Carlo Giansante;

Angew. Chem. Int. Ed.2022, e202201747 https://doi.org/10.1002/anie.202201747

Abstract: Here we present a colloidal approach to synthesize bismuth chalcohalide nanocrystals (BiEX NCs, in which E=S, Se and X=Cl, Br, I). Our method yields orthorhombic elongated BiEX NCs, with BiSCl crystallizing in a previously unknown polymorph. The BiEX NCs display a composition-dependent band gap spanning the visible spectral range and absorption coefficients exceeding 105 cm−1. The BiEX NCs show chemical stability at standard laboratory conditions and form colloidal inks in different solvents. These features enable the solution processing of the NCs into robust solid films yielding stable photoelectrochemical current densities under solar-simulated irradiation. Overall, our versatile synthetic protocol may prove valuable in accessing colloidal metal chalcohalide nanomaterials at large and contributes to establish metal chalcohalides as a promising complement to metal chalcogenides and halides for applied nanotechnology.