Design improvements for the polyhedral specular reflector spectrum-splitting module for ultra-high efficiency (&amp;#x003E;50%)

Eisler, Carissa N.; Warmann, Emily C.; Flowers, Cristofer A.; Dee, Michelle; Kosten, Emily D.; Atwater, Harry A.

doi:10.1109/pvsc.2014.6925367

Cited by 6 publications

(4 citation statements)

References 15 publications

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“…Instead, the 90% optical efficiency used to predict module performance serves as a baseline performance requirement for any spectrum splitting concept under consideration. This value is consistent with reported spectrum splitting optical efficiencies . Similarly, the 98% efficiency of the DC electrical system serves as a target for power management systems .…”

Section: Resultssupporting

confidence: 90%

Design of photovoltaics for modules with 50% efficiency

Warmann

Flowers

Lloyd

et al. 2017

Energy Science & Engineering

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A wide variety of photovoltaic cell technologies have shown dramatic performance improvements over the past decade, yet the prospect of a practical module capable of 50% efficiency remains remote. Experimentally achieved singlecell devices have achieved a record efficiency of 28.8% [1], which is close to the theoretical limit of 33.8% for such devices [2]. However, the single-cell limit is far below the fundamental efficiency limit for solar energy conversion of 74.0% for global illumination and 92.8% for direct [2] because a single pn junction can only efficiently convert photons with energy close to the value of its energy bandgap. The best single junction cell will lose more than 40% of the energy in the incident light to transmission of subbandgap photons and thermalization of carriers with photon energy in excess of the bandgap [3]. Spectrum splitting, which divides the solar spectrum into spectral bands of different energy and directs the bands onto multiple subcells with bandgap values matched to the energy of their photon allocation, is a necessary feature of any photovoltaic design capable of achieving >33.8% efficiency. The use of multiple subcells to increase conversion efficiency is well known. In these designs, the subcells are grown monolithically in a stacked configuration and are electrically in series. The incident spectrum is divided among the subcells by sequential absorption, with the top subcells absorbing and converting high energy photons

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Section: Resultssupporting

confidence: 90%

Design of photovoltaics for modules with 50% efficiency

Warmann

Flowers

Lloyd

et al. 2017

Energy Science & Engineering

Self Cite

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“…Although they might be suitable for point focusing systems [12][13][14][15][16], they have only recently been deployed in linear concentrators (see Section 5.2). Such linear concentrators ( Fig.…”

Section: Figurementioning

confidence: 99%

Spectral light management for solar energy conversion systems

2016

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Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro-and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

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“…Figure 1a shows a schematic for a spectrum-splitting device in which direct irradiance enters the input aperture onto a series of spectrum-splitting optical elements that reflect progressively longer wavelength light into a series of receivers. Details of proposed secondary receivers are given in Table 1 including cell [3] and filter characteristics [4]. Ideal filters would have on average >85% reflectivity within the target band and >90% transmission for longer wavelengths.…”

Section: Introductionmentioning

confidence: 99%

“…High transmission for longer wavelengths is important, since erroneously transmitted photons can still be converted in a lower bandgap cell but erroneously reflected light is lost completely in a higher bandgap cell. Aperiodic dielectric stack filters have been designed and demonstrated to have optical splitting efficiency consistent with ultrahigh efficiency [4]. These gratings however require precise and slow vacuum deposition fabrication, which leads to high costs.…”

Section: Introductionmentioning

confidence: 99%

Resonant dielectric high-contrast gratings as spectrum splitting optical elements for ultrahigh efficiency (>50%) photovoltaics

Darbe

Atwater

2015

2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC)

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Resonant dielectric gratings are explored as low cost spectrum-splitting optical elements in a photovoltaic device architecture that incorporates many independently connected subcells of different bandgaps for ultrahigh efficiency (>50%). Gratings can have broadband reflectivity by appropriately offsetting grating resonances. Subwavelength feature sizes suppress diffraction, and the high-refractive index of the grating layer leads to relatively angle-insensitive reflectance. Gratings can be fabricated by nanoimprint lithography, making them a scalable and economical option for photovoltaic applications. Using these gratings to create a series of dichroic filters to separate incident solar light into a series of bands which can then be coupled into independent subcells has potential for high efficiency by overcoming losses due to lack of absorption of subbandgap photons and thermalization of excited carriers which account for loss of over 40% of incident power on singlejunction solar cells. Independent connection and physically separated subcells permit freer bandgap selection and relieve the current-matching constraint which limits conventional monolithic tandem multijunction cell efficiency.Index Terms -III-V semiconductor materials, optical filters, optical metamaterials, photovoltaic systems, reflectivity, resonance, silicon splitting.

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Design improvements for the polyhedral specular reflector spectrum-splitting module for ultra-high efficiency (>50%)

Cited by 6 publications

References 15 publications

Design of photovoltaics for modules with 50% efficiency

Design of photovoltaics for modules with 50% efficiency

Spectral light management for solar energy conversion systems

Resonant dielectric high-contrast gratings as spectrum splitting optical elements for ultrahigh efficiency (>50%) photovoltaics

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