All-inorganic nanocrystals (NCs) are of great importance in a range of electronic devices. However, current all-inorganic NCs suffer from limitations in their optical properties, such as low fluorescence efficiencies. Here, we develop a general surface treatment strategy to obtain intensely luminescent all-inorganic NCs (ILANs) by using designed metal salts with noncoordinating anions that play a dual role in the surface treatment process: (i) removing the original organic ligands and (ii) binding to unpassivated Lewis basic sites to preserve the photoluminescent (PL) properties of the NCs. The absolute photoluminescence quantum yields (PLQYs) of red-emitting CdSe/ZnS NCs, green-emitting CdSe/CdZnSeS/ZnS NCs and blue-emitting CdZnS/ZnS NCs in polar solvents are 97%, 80% and 72%, respectively. Further study reveals that the passivated Lewis basic sites of ILANs by metal cations boost the efficiency of radiative recombination of electron-hole pairs. While the passivation of Lewis basic sites leads to a high PLQY of ILANs, the exposed Lewis acidic sites provide the possibility for in situ tuning of the functions of NCs, creating opportunities for direct optical patterning of functional NCs with high resolution.

The transformation pathways in cluster regions have received only limited attention, and the fundamental issues involved require in-depth study. Here, we demonstrate the formation and transformation mechanisms in Cd-based MSCs by studying spectroscopically pure (CdS) 13 MSCs. We show that the molecular formula of the obtained CdS MSCs is [(CdS) 13 (RNH 2 ) 13 ] and that the experimental estimate of the diameter is approximately 0.75 nm. Further study reveals that, in addition to the amine-bilayer templated synthesis route, two other transformation pathways exist in the semiconductor cluster region. Pathway 1 involves intercluster transformation and undergoes a process of dissolution and regrowth, while Pathway 2 is an anion exchange reaction. The latter is considered to be difficult in nanocrystal synthesis and is observed for the first time in semiconductor MSCs. The present findings not only enrich the cluster family but also provide profound insight into the transformation mechanisms between MSCs, which will further shed light on the synthesis of nanocrystals.

No abstract

Surface engineering is a critical step in the functionalization of nanomaterials to improve their optical and electrochemical properties. However, this process remains a challenge in II-VI magic-size clusters (MSCs) due...

Stabilizing nanocrystals (NCs) with high fluorescence quantum efficiency in suitable solvents and tuning of their optical properties precisely are critical for designing and assembling optoelectrical devices. Here, we demonstrated that by replacing the original X-type ligand (R-COO-) with triethylborate (TEB), zinc-blend structure nanoplatelets (Zb-NPLs) turn from hydrophobic to hydrophilic and are quite stable in polar solvents. More importantly, a large shift of 253 meV is observed for the TEB-passivated NPLs, which can be attributed to the strain of the crystal lattice and the electron or hole delocalizing into the ligand shell. It is worth noting that unlike conventional inorganic ligands, such as metal chalcogenide complexes or halides that quench fluorescence, TEB-treated NPLs maintain 100% of their original brightness in polar solvents with a slight increase in full width at half maximum (FWHM, 32 nm). Furthermore, we explored the possibility of employing TEB as surface ligands for NPLs with different thicknesses and compositions. We believe the discovery of new surface chemistry using borate-related ligands can greatly expand the potential application areas of NPLs.