Evolution of Photoluminescent CdS Magic-Size Clusters Assisted by Adding Small Molecules with Carboxylic Group

Abstract

We report our investigation on the formation of photoluminescent CdS magic-size clusters (MSCs), which exhibit absorption peaking at 373 nm, along with sharp band edge emission at ∼385 nm. Denoted as MSC-373, the MSCs were synthesized from the reaction of cadmium oleate (Cd­(OA)2) and S powder in 1-octadecene at room temperature, together with the addition of acetic acid (HOAc) or acetate salts (M­(OAc)2, M = Zn and Mn) during the prenucleation stage (120 °C). The morphology of as-synthesized MSC-373 was dot-like, which could be altered to flake-like morphology after purification. We found the formation of MSC-373 was related to the ligand exchange, resulting from the addition of small molecules with carboxylic group. The addition of HOAc not only promotes the formation of CdS MSC-373 but suppresses the formation of MSC-311 and nucleation and growth of quantum dots (QDs). When the amount of HOAc addition was increased, another photoluminescent CdS MSCs, namely, MSC-406, evolved. This study provides an overall understanding of the CdS MSC-373 and introduces a new approach to synthesize photoluminescent CdS MSCs.

Reeling them in: Ph2PSiMe3 in the sequential formation of InP magic-sized clusters

“…This growth in discrete jumps is a familiar concept in the more established II-VI QD systems. 29 The sequential conversion of 365-InP to 386-InP (InI 3 ) and 386-InP to 430-InP for InCl 3 extends this principle to InP MSCs for the first time.…”

“…This growth in discrete jumps is a familiar concept in the more established II-VI QD systems. 29 The sequential conversion of 365-InP to 386-InP (InI3) and 386-InP to 430-InP for (InCl3) extends this principle to InP MSCs for the first time. Reviewing our experimental observations in their totality has allowed us to put forward a mechanistic hypothesis for our system (Figure 5).…”