Semiconductor nanostructures and nanoassemblies: a new perspective on their syntheses, properties and photophysical behaviour.

In the first part of this research, attempts have been made to use single-molecule precursors [X2In(m-PR2)]2 (X = Me, CH2Ph; R = CMe3, SiMe3) to generate nano-dimensional InP through thermal degradation. Thermolysis of the di-tert-butyl precursors always led to In0, whereas, the trimethylsilyl precursors formed In0 only in presence of hexadecylamine, but in the absence of the amine could form InP nanoparticles. Thermolysis of [(PhCH2)2InP(SiMe3)2]2, a new precursor, gives either InP nanoparticles or nanowires, depending on the presence or absence of stearic acid. This provided a simple and rapid method for the synthesis of InP nanowires, for the first time, without the need of any protic coreagents or surfactants. The wires were grown using the hot injection technique and their formation relies on the SLS mechanism. We also showed for the first time that the lengths of the nanowires can be conveniently controlled by adjusting only the injection temperature and were able to grow wires at a temperature as low as 160 ℃. Finally, the indium metal at the base of each wire, an obvious outcome of the SLS mechanism, can be easily removed under mild non-corrosive conditions. The second part of the thesis describes attempts to couple group II-VI (CdSe, ZnSe) quantum dots with subphthalocyanines (SubPcs) to form hybrid nanoassemblies. The SubPcs chosen, carried pendant pyridyl moieties for coordination to the nanoparticle surfaces. However, ZnSe iii did not show any ligand binding, whereas, CdSe formed a stable complex, with an association constant either larger than or comparable to previously reported values for other macrocycles. The QD : ligand ratio was determined by a number of independent experimental methods (UV, PL, NMR spectroscopy, quenching studies). The CdSe-SubPc formed an efficient donor-acceptor system in terms of photophysical properties, and energy flow within such systems was found to occur primarily through FRET mechanism.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of East Anglia

Year dc:date.issued

2013

Author dc:creator

• Banerjee, Chiranjib

Language dc:language

en