Free-standing PbSe nanocrystals, including quantum wires, multipods, quantum rods, quantum dots, and cubes, were produced in a colloidal solution in the presence of alkyl-diamine solvent at 10−117 °C. The morphology of the nanocrystals was governed by a solvent coordinating molecular template mechanism, which was further adjusted by the temperature and duration of the reaction. Crystalline wires with diameters of approximately 20 nm and lengths of 1−5 μm were formed at the lowest temperatures, while quantum rods (with an aspect ratio of ∼5) and cubes (with 100−500 nm edge) were formed at elevated temperatures.

Single-exciton, biexciton, triexciton, and quadraexciton bands were resolved in the microphotoluminescence spectrum of a single CdTe/CdSe core-shell colloidal quantum dot, revealing nearly blinking-free behavior. Multiexcitons were generated by a sequential filling of electronic shells with the increase of a continuous-wave excitation power, and their probability was evaluated under steady-state conditions. A partial carriers' delocalization was determined at the core-shell interface, and an exciton binding energy was estimated by a second-order perturbation theory.

The paper presents a new synthesis route for the formation of spherical-shaped CdTe semiconductor nanocrystal quantum dots (NQDs) using colloidal solutions with oleic acid and trioctylphosphine stabilizers. The synthesis includes the occurrence of in situ precipitation of crystalline Cd0 nanoparticles prior to the formation of CdTe NQDs. The experimental evidence suggests that the existence of Cd0 induces a regulation of the precursor supply during the CdTe NQDs growth, inducing a control of the growth kinetics and determination the final shape of the NQDs. Also, the results suggest that the initial Cd/Te molar ratio controls the NQDs' quality, with excess Cd precursor inducing the generation of NQDs with exceptionally high emission QE up to 80% at room temperature.

Recent years have witnessed thriving progress of flexible and portable electronics, with very high demand for cost-effective and tailor-made multifunctional devices. Here, we report on an ingenious origami hierarchical sensor array (OHSA) written with a conductive ink. Thanks to origami as a controllable hierarchical framework for loading ink material, we have demonstrated that OHSA possesses unique time-space-resolved, high-discriminative pattern recognition (TSR-HDPR) features, qualifying it as a smart sensing device for simultaneous sensing and distinguishing of complex physical and chemical stimuli, including temperature, relative humidity, light and volatile organic compounds (VOCs). Of special importance, OSHA has shown very high sensitivity in differentiating between structural isomers and chiral enantiomers of VOCs – opening a door for wide variety of unique opportunities in several length scales.

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