Low-Temperature, Solution-Based Sulfurization and Necking of PbS CQD Films

Abstract

Lead sulfide colloidal quantum dots (CQDs) are a promising optoelectronic material. The optoelectronic functionality of PbS CQD films largely depends on the anionic ligands that passivate the Pb-rich surface of the CQDs’ inorganic cores. Herein, we report a simple solution-based method for fabricating PbS CQD films using sulfur as the ligand. In turn, passivation of the CQDs with sulfur promotes the chemisorption of oxygen. Overall, this approach results in efficient removal of the original organic ligands and in enhanced interdot electronic coupling. The CQD films present increased p-type doping, higher majority carrier mobility, and higher photoresponsivity as compared to state-of-the-art halide-passivated CQD films. The simple postsynthetic sulfurization strategy described herein can be potentially applied in a variety of metal sulfide and selenide nanomaterials whose optoelectronic functionalities in part depend on the chalcogen to metal atomic ratio.

Chemically encoded self-organized quantum chain supracrystals with exceptional charge and ion transport properties

“…S1), which demonstrate enhanced necking and electronic coupling from long-range ordered QC superstructures. 5,6 Typical PbS rock-salt cubic crystalline structure 45 was determined by characteristic X-ray diffraction (XRD) patterns and, as indexed in Fig. 1c, the attachment of these constituted QDs were found preferentially along the <100> axis with more than microns length scales (inset of Fig.…”

“…Nanostructured materials lie at the forefront of the state of the art energy conversion and storage technologies because of their excellent mechanical and electrical properties. [1][2][3][4][5][6][7][8] Spontaneous assembly small building blocks into superstructures with distinct functionality are scientific challenges in fundamental science (e.g., the origin of life) and nanotechnologies. [9][10][11][12] Elaborately self-organized superstructures from low-dimensional materials could dramatically improve their optical-electrical properties as well as providing new collective phenomena through long-range ordered interparticle cross-linking.…”

Stoichiometric control of the density of states in PbS colloidal quantum dot solids

“…Stavrinadis et al . reported sulfurization of PbS particles by exposing the as-deposited thin films to an organosulfur compound ( 18 ). Although these works are groundbreaking and provide proof-of-concept results, all of the described methods have drawbacks; either only full surface coverage with the chalcogen can be realized or the stoichiometry is inhomogeneous throughout the film.…”

Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivation

“… 26 It is not expected that these large crystal grains would exhibit any PL emission that would resemble that of the pristine QDs. 27 …”