Fig. 2

a Schematic diagram of a PbS CQD consisting of a semiconductor core and surface ligands (reprinted with permission from ref. 8, Copyright 2014 American Association for the Advancement of Science). b Charge carrier mobility of PbS CQD films with various surface ligand length (reprinted with permission from ref. 9, Copyright 2013 American Chemical Society). c Energy band position of PbS CQD films for d different surface ligands (reprinted with permission from ref. 10, Copyright 2013 American Chemical Society). Air stability analysis using e the absorbance spectrum and f quantum yield of PL as a function of storage time and its dependence on NH₄Cl treatment on the surface of PbSe CQDs (reprinted with permission from ref. 11, Copyright 2014 American Chemical Society)