Quantum dot-labelled polymer beads by suspension polymerisation

CdSe quantum dots with polymerisable ligands have been incorporated into polystyrene beads, via a suspension polymerisation reaction, as a first step towards the optical encoding of solid supports for application in solid phase organic chemistry

High efficiency nanoparticle solution-processed Cu(In,Ga)(S,Se)2 solar cells

Thin film Cu(In,Ga)(S,Se)2-based (generally referred to as CIGS) solar cells represent a promising alternative to conventional crystalline silicon solar cells due to their high efficiencies, reduced cost and better material utilisation. In recent years it has been demonstrated that it is possible to form thin films by annealing nanoparticulate material such that the nanoparticles coalesce to form large grained thin films. In this paper, we present a 13.8 % efficient CIGS solar cell derived from printed nanoparticle inks. The approach was successfully extended to fabricate monolithic devices on larger substrates. These results demonstrate that low-cost, non-vacuum printing of CIGS nanoparticles has great potential to achieve high efficiencies and reduce the performance gap with the more traditional vacuum co-evaporation and sputtering techniques

Analysis and comparison of different selenization routes for nanoparticle ink deposited Cu(In1-xGax)(SeyS1-y)2 solar cells

This paper investigates the effect of using different selenization sources, namely elemental Se and H2Se, on Cu(In1-xGax)(SeyS1-y)2 devices derived from depositions of nanoparticle inks. Nanoparticles used in this synthesis are chalcogenides (e.g. CuInGaS). The effect of the selenization species has a large effect on the performance and electrical properties of these devices. Elemental selenized devices show higher efficiencies (>16%) compared to H2Se processed devices (<12%). Various techniques are used in this study, including Raman spectroscopy, TEM, I-V-T, EQE, admittance spectroscopy and C-V-T to identify the difference in performance between the two selenization methods. Differences are observed in both the bulk and interface properties of the devices

Ultrafast exciton dynamics in InAs/ZnSe nanocrystal quantum dots

Colloidal nanocrystal quantum dots with a band gap in the near infra-red have potential application as the emitters for telecommunications or in vivo imaging, or as the photo-absorbing species in next generation solar cells or photodetectors. However, electro- and photoluminescence yields and the efficiency with which photo-generated charges can be extracted from quantum dots depend on the total rate of recombination, which can be dominated by surface-mediated processes. In this study, we use ultrafast transient absorption spectroscopy to characterise the recombination dynamics of photo-generated charges in InAs/ZnSe nanocrystal quantum dots. We find that recombination is dominated by rapid, sub-nanosecond transfer of conduction band electrons to surface states. For the size of dots studied, we also find no evidence of significant multiple exciton generation for photon energies up to 3.2 times the band gap, in agreement with our theoretical modellin