Optical concentration can lower the cost of solar energy conversion by reducing photovoltaic cell area and increasing efficiency. Luminescent concentrators offer an attractive approach to combined spectral spatial both specular diffuse light without tracking, but they have been plagued luminophore self-absorption losses when employed on practical size scales. Here, we introduce doped semiconductor nanocrystals as a new class phosphors for use in luminescent concentrators. In proof-of-concept...

A diffusion-based synthesis of doped colloidal semiconductor nanocrystals is demonstrated. This approach involves thermodynamically controlled addition both impurity cations and host anions to preformed seed under equilibrium conditions, rather than kinetically doping during growth. chemistry allows thermodynamic crystal compositions be prepared without sacrificing other trapped properties such as shape, size, or crystallographic phase. thus shares some similarities with cation-exchange...

Colloidal halide perovskite nanocrystals of CsPbCl3 doped with Yb3+ have demonstrated remarkably high sensitized photoluminescence quantum yields (PLQYs), approaching 200%, attributed to a picosecond quantum-cutting process in which one photon absorbed by the nanocrystal generates two photons emitted dopants. This is thought involve charge-neutral defect cluster within nanocrystal's internal volume. We demonstrate that Yb3+-doped can be converted postsynthetically CsPb(Cl1- xBr x)3 without...

Luminescent solar concentrators (LSCs) use down-converting luminophores embedded in a waveguide to absorb sunlight and deliver high irradiance, narrowband output light for driving photovoltaic other energy conversion devices. Achieving technologically useful level of optical gain requires bright, broadly absorbing, large-Stokes-shift incorporated into low-loss waveguides, combination that has long posed challenge the development practical LSCs. The recent introduction giant effective Stokes...

Yb3+-doped halide perovskites have recently emerged as extraordinarily promising materials for solar spectral downconversion applications because of their extremely high photoluminescence quantum yields nearly 200%, attributable to a highly efficient picosecond quantum-cutting process. One the major roadblocks widespread application these is saturation under modest photoexcitation fluences. In this study, we examine excitation-fluence dependence CsPb(Cl1–xBrx)3 nanocrystal develop...

One of the most prominent signatures transition-metal doping in colloidal nanocrystals is formation charge carrier-induced magnetization dopant spin sublattice, called exciton magnetic polaron (EMP). Understanding direction EMP formation, however, still a major obstacle. Here, we present series temperature-dependent photoluminescence studies on single Mn2+:CdSe/CdS core/shell quantum dots (QDs) performed vector field providing unique insight into interaction between individual excitons and...

Electrical spin manipulation remains a central challenge for the realization of diverse spin-based information processing technologies. Motivated by demonstration confinement-enhanced sp-d exchange interactions in colloidal diluted magnetic semiconductor (DMS) quantum dots (QDs), such materials are considered promising candidates future spintronic or spin-photonic applications. Despite intense research into DMS QDs, electrical control their and magneto-optical properties daunting goal. Here,...

We examine the effects of CdS shell growth on photochemical reduction colloidal CdSe quantum dots (QDs) and describe spectroscopic properties resulting n-type CdSe/CdS QDs. greatly slows electron trapping. Because this improvement, complete two-electron occupancy 1Se conduction-band orbital is achieved in QDs found to be much more stable than past experiments. Simultaneous photoluminescence at two different energies now observed from possessing excess electrons, reflecting competing...

Solution processing of semiconductor nanocrystal (NC) solids represents an attractive platform for the development next-generation optoelectronic devices. In search enhanced light-emitting performance, NC are typically designed to have large interparticle gaps that minimize exciton diffusion dissociative sites. This strategy, however, reduces electrical coupling between nanoparticles in a film, making injection charges inefficient. Here, we demonstrate bright emission from can be achieved...

iv Acknowledgments v Table of Figures and Tables ix Chapter 1: Introduction 1 1.1 World Energy Use 1.2 Renewable Options 2 1.2.1 Hydroelectric 1.2.2 Wind Power 3 1.2.3 Nuclear 1.2.4 Geothermal 1.2.5 Biomass Biofuel 4 1.2.6 Solar 1.3 Photovoltaics 5 1.4 Concentration Methods 6 1.4.1 Parabolic Troughs 7 1.4.2 Tower 8 1.4.3 Fresnel Lenses 1.4.4 Dish 1.4.5 Concentrator Summary References 9 2: Luminescent Concentrators 11 2.1 Intro to 2.2 LSC Design Advantages 12 2.3 Performance 13 2.4 Materials...

The polarization of photoluminescence emitted from anisotropic nanocrystals directly reflects the symmetry eigenstates involved in recombination process and can thus be considered as a characteristic feature nanocrystal. We performed resolved magneto-photoluminescence spectroscopy on single colloidal Mn2+:CdSe/CdS core–shell quantum dots wurtzite crystal symmetry. At zero magnetic field, distinct linear pattern is observed, while applying field enforces circularly polarized emission with...