Wen-Xu Zhang,Jing-Shuai Chen,Xing-Pei Liu,Chang-Jie Mao,Bao-Kang Jin
The extreme sensitivity of perovskite nanoparticles to water has seriously hindered their application. At present, all inorganic perovskite nanocrystals (NCs) have received extensive attention due to their excellent photoelectric properties. A highly hydrophilic composite CsPbBr3/TDPA NCs was synthesized in the presence of oleylamine molecules, which greatly enhanced its water stability. The electrochemiluminescence (ECL) intensity and stability of the composites are much higher than those of single CsPbBr3 quantum dots (QDs). For the first time, we have developed a sensor for the specific detection of nitrobenzene using the ECL method. It was found that nitrobenzene could significantly enhance the ECL signal of CsPbBr3/TDPA NCs. The ECL sensor showed a good linear relationship with the concentration of nitrobenzene in the range of 1 mM to 0.1 μM, and the detection limit was as low as 0.05 μM (S/N = 3). This work provides a new idea for the development of nitrobenzene ECL sensors.
Yang Ping,Chen Hsueh Shin,Zhang Qiang,Shi Ruixia,Wang Junpeng,Che Quande
To investigate the shell deposited kinetics, CdSe quantum dots (QDs) and nanorods (NRs) with a maximum length of 17 nm were fabricated via organic synthesis routes. CdSe with a hexagonal crystal structure (wurtzite) favors epitaxial growth on the {002} surfaces when well-controlled conditions were used. The morphologies and sizes of CdSe samples depended strongly on chemicals and temperature. In the case of 320 °C, CdSe NRs with adjusted length of 7–17 nm were obtained from trioctylphosphine oxide (TOPO) and tetradecylphosphonic acid (TDPA). In contrast, short CdSe NRs (less than 10 nm) were created from octadecylphosphonic acid (ODPA) and trioctylamine (TOA). Spherical CdSe QDs were further fabricated using stearic acid (SA) and TOPO at 300 °C. CdSe cores were coated with Cd 0.5 Zn 0.5 S and CdTe shells. Anisotropic growth occurred during shell deposition because CdS shells grown preferentially on the {001} facet of the CdSe core. In the case of CdSe core prepared from TOPO and TDPA, CdSe/Cd 0.5 Zn 0.5 S core/shell samples prepared from long CdSe NRs (more than 10 nm) revealed a peanut morphology while the core/shell samples created from short ones (less than 10 nm) exhibited a spherical morphology. All of the CdSe/Cd 0.5 Zn 0.5 S core/shell samples revealed a similar length to that of the CdSe cores. This phenomenon was also observed for the core/shell samples fabricated using CdSe NRs prepared by ODPA and TOA. This is ascribed to the well-developed crystal structure of CdSe NRs fabricated using an organic synthesis at high temperature. In contrast, this anisotropic growth did not occur when spherical CdSe QDs prepared from SA and TOPO and the shell (Cd 0.5 Zn 0.5 S) coating carried out using SA and TOA. To indicate the shell depositing process, CdSe NRs fabricated using TDPA and TOPO were coated with a CdTe shell. CdTe monomers were deposited on the middle and tip parts of the CdSe NRs to form a tetrapod-like morphology at 220 °C. This is ascribed to the large difference of structure of CdSe (hexagonal) and CdTe (zinc blende).
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