Research on the luminescent solar concentrator (LSC) over the past thirty-odd years is reviewed. The LSC is a simple device at its heart, employing a polymeric or glass waveguide and luminescent molecules to generate electricity from sunlight when attached to a photovoltaic cell. The LSC has the potential to find extended use in an area traditionally difficult for effective use of regular photovoltaic panels: the built environment. The LSC is a device very flexible in its design, with a variety of possible shapes and colors. The primary challenge faced by the devices is increasing their photon-to-electron conversion efficiencies. A number of laboratories are working to improve the efficiency and lifetime of the LSC device, with the ultimate goal of commercializing the devices within a few years. The topics covered here relate to the efforts for reducing losses in these devices. These include studies of novel luminophores, including organic fluorescent dyes, inorganic phosphors, and quantum dots. Ways to limit the surface and internal losses are also discussed, including using organic and inorganic-based selective mirrors which allow sunlight in but reflect luminophore-emitted light, plasmonic structures to enhance emissions, novel photovoltaics, alignment of the luminophores to manipulate the path of the emitted light, and patterning of the dye layer to improve emission efficiency. Finally, some possible ‘glimpses of the future’ are offered, with additional research paths that could result in a device that makes solar energy a ubiquitous part of the urban setting, finding use as sound barriers, bus-stop roofs, awnings, windows, paving, or siding tiles.

Thirty Years of Luminescent Solar Concentrator Research: Solar Energy for the Built Environment

Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review

Enhancing the performance of silicon solar cells via the application of passive luminescence conversion layers

A theoretical analysis of third-order nonlinear interactions of focused laser beams is performed for the processes \omega_{1} + \omega_{2} + \omega_{3} \rightarrow \omega_{4}, \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} , and \omega_{1} - \omega_{2} - \omega_{3} \rightarrow \omega_{4} . The total power and far-field beam profile of the generated radiation is related to the total powers of the fundamental beams, to the tightness and location of the focus, and to the value of the difference between the wave vectors of the generated radiation and driving polarization. The optimum degree of wave-vector mismatch as a function of tightness and location of focus is determined for each of the three processes. The process \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} is found to be unique in that it is always optimized by focusing as tightly as possible. Experimental results, which verify the theory for the processes \omega_{1} + \omega_{2} + \omega_{3} \rightarrow \omega_{4} and \omega_{1} + \omega_{2} - \omega_{3} \rightarrow \omega_{4} , are presented.

Effects of focusing on third-order nonlinear processes in isotropic media

Heterojunction band offset engineering

Tunable Coherent Vacuum-Ultraviolet Generation in Atomic Vapors

The effect of fluorescent wavelength shifting on solar cell spectral response

Order-Disorder Transition in Single-Crystal Silicon Induced by Pulsed uv Laser Irradiation

A doped or undoped photoresponsive material having metallic precipitates, and a PiN photodiode utilizing the material for detecting light having a wavelength of 1.3 micrometers. The PiN photodiode includes a substrate having a first compound semiconductor layer disposed thereon. The PiN photodiode further includes an optically responsive compound semiconductor layer disposed above the first compound semiconductor layer. The optically responsive layer includes a plurality of buried Schottky barriers, each of which is associated with an inclusion within a crystal lattice of a Group III-V material. The PiN device also includes a further compound semiconductor layer disposed above the optically responsive layer. For a transversely illuminated embodiment, waveguiding layers may also be disposed above and below the PiN structure. In one example the optically responsive layer is comprised of GaAs:As. The GaAs:As exhibits a very low room temperature dark current, even under forward bias conditions, and a responsivity to 1.3 micrometer radiation modulated at frequencies greater than 1 GHz.

Method of making a compound semiconductor having metallic inclusions

The invention provides a capacitor having increased capacitance comprising one or more main vertical trenches (16) and one or more lateral trenches (18) extending off the main vertical trench. The capacitor has alternating first and second regions (12, 14), preferably silicon and non-silicon regions (for example, alternating silicon and germanium or alternating silicon and carbon regions). The etch characteristics of the alternating regions are utilized to selectively etch lateral trenches thereby increasing the surface area and capacitance of the capacitor. A method of fabricating the capacitors is also provided.

Rodney T. Hodgson

Papers

Tunable Coherent Vacuum-Ultraviolet Generation in Atomic Vapors

The effect of fluorescent wavelength shifting on solar cell spectral response

Order-Disorder Transition in Single-Crystal Silicon Induced by Pulsed uv Laser Irradiation

Method of making a compound semiconductor having metallic inclusions

High area capacitor formation using material dependent etching