Fig. 1: Synthesis of PbxCd1−xSe QD gels.
From: Atomically dispersed Pb ionic sites in PbCdSe quantum dot gels enhance room-temperature NO2 sensing
a Comparison of CdS, CdSe, PbS, and PbSe QD gels with 110 state-of-the-art room-temperature p-type semiconductor NO2 sensors in the literature in terms of sensor response and recovery time. b Schematic diagram for the synthesis of PbxCd1−xSe QD gels (x = 0.003, 0.02, 0.04, 0.09, 0.17, 0.40, and 1.0) via cation exchange using different Pb(NO3)2 concentrations. c–h STEM images of c, d CdSe QDs, e, f CdSe gel, and g, h Pb0.09Cd0.91Se gel at low and high magnification, inset: the corresponding photographs. Crystallites in the high-resolution images are color-coded based on their lattice fringes, corresponding to the {100}, {101}, {102}, {103}, {110}, {112}, and {002} planes of hexagonal CdSe. i Nitrogen adsorption–desorption isotherms and j Barrett–Joyner–Halenda pore-size distributions of CdSe, Pb0.09Cd0.91Se, Pb0.17Cd0.83Se, and Pb0.40Cd0.60Se QD gels.
