Extended Data Fig. 3: Effect of chloride passivation on physical properties.

a, TR-PL spectra and average decay lifetimes of solutions of core, C/S, C/S/S and C/S/S-Cl(l) QDs (excitation at 405 nm, measured at each emission peak). b, c, Photoluminescence spectra (b) and TR-PL spectra and average decay lifetimes (c) of films of C/S/S, C/S/S-Cl(l) and C/S/S-Cl(f) QDs. d, TGA curves of C/S/S, C/S/S-Cl(l) and C/S/S-Cl(l) aggregates. The shaded area indicates the weight loss of OA ligands. e, FT-IR spectra of films prepared with C/S/S, C/S/S-Cl(l) and C/S/S-Cl(f) QDs. Inset, magnification of the spectra showing asymmetric (v₁) and symmetric (v₂) vibrations of the carboxylate group with aliphatic stretching (v₃). The wavenumber difference between v₁ and v₂ is indicated (145 cm⁻¹) to explain the binding mode of oleate corresponding to briging bidentate. f–h, Size of QDs dispersed in octane and measured with DLS: C/S/S (f), C/S/S-Cl(l) (g) and C/S/S-Cl(l) (h) aggregates. i–l, High-resolution XPS spectra of elements in C/S/S, C/S/S-Cl(l) and C/S/S-Cl (f): zinc 2p₃ (i), selenium 3d (j), sulfur 2p (k) and chlorine 2p (l).