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PbS quantum dots have been synthesized using a PbBr 2 precursor and the halide content has been examined. Slower reaction kinetics for quantum dots growth relative to the use of PbCl 2 was observed for PbBr 2 , giving a possible route to increased control over quantum dot size with in situ passivation.Unambiguous determination of the surface conditions of nanomaterials is still a developing area of science, pushing the limits of current microscopy and analytical techniques. Contributions to a rigorous form of nanomaterial surface analysis are made here using X-ray photoelectron spectroscopy to analyse bonding in detail. Atomic resolution TEM is applied to produce energy dispersive X-ray spectroscopy maps with state of the art resolution. This analysis has been applied to air-stable halide terminated PbS nanoparticles, which is a nanomaterial of central importance for quantum confined solar cell applications. Chemical analysis from X-ray photoelectron spectroscopy is consistent with Br surface termination and high resolution energy dispersive X-ray spectroscopy (EDS) maps also show a positive spatial correlation for Br with quantum dot location. An observed excess Br content is attributed to the presence of bromine terminated PbS quantum dots nuclei in the final colloid.

PbS QDs are studied as attractive candidates to be applied as hot carrier solar cell absorbers.

The hot carrier (HC) solar cell is one of the most promising advanced photovoltaic concepts. It aims to minimise two major losses in single junction solar cells due to sub-band gap loss and thermalisation of above band gap photons by using a small bandgap absorber, and, importantly, collecting the photo-generated carriers before they thermalise. In this paper we will present recent development of the two critical components of the HC solar cell, i.e., the absorber and energy selective contacts (ESCs). For absorber, fabrication and carrier cooling rates in potential bulk materials — hafnium nitride, zirconium nitride, and titanium hydride are presented. Results of ESCs employing double barrier resonant tunneling structures Al2O3/Ge quantum well (QW)/Al2O3 and Al2O3/PbS quantum dots (QDs)/Al2O3 are also presented. These results are expected to guide further development of practical HC solar cell devices.

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