Recent advances in heavily doped plasmonic copper chalcogenides: from synthesis to biological application

Copper-based chalcogenide compounds have emerged as alternative materials to Cd- or Pb-based traditional semiconductors and have drawn significant attention. Compared with widely reported semiconductors, copper chalcogenide nanocrystals (NCs) with abundant copper defects and vacancies present p-type features. Additionally, the migration of free hole carriers in copper-based chalcogenide NCs produced a metal-like local surface plasmon resonance (LSPR) effect. In this review, we focused on the plasmonic copper chalcogenide NCs achieved through a heavily doped strategy. The copper sulfur compounds with versatile atomic ratios and complex crystal structures exhibit rich electrical, optical, and magnetic properties, making them highly promising for a broad range of applications, from energy conversion to biomedical fields. Therefore, our main focus is on the classification of copper chalcogenide synthesis strategies, theoretical studies of doping, doping strategies, and biological applications. We aim to analyze the trends of copper-based chalcogenide nanomaterials for clinical applications by summarizing previous studies and presenting designs and concepts in a brief manner.