68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance

Helmers, Henning; López, E.; Höhn, Oliver; Lackner, David; Schön, Jonas; Schauerte, Meike; Schachtner, Michael; Dimroth, Frank; Bett, Andreas W.

doi:10.1002/pssr.202170026

Cited by 38 publications

(34 citation statements)

References 27 publications

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“…The higher open circuit voltages and the higher currents for sample C indicate that the dry mesa etching process is advantageous for these multi-junction PPCs. For the highest measured input powers the gain in VOC drops which is attributed to worse thermal coupling of the flexible wafers to the measurement chuck and, thus, more pronounced heating of the DUT during measurement at such high irradiance; similar as observed in other measurements [1].…”

Section: A Measurements Under 809 Nm Lightsupporting

confidence: 80%

“…Photonic power converters (PPCs) are photovoltaic cells that are optimized for artificial light and are used as receivers for optical power transmission systems based on a laser or a lightemitting diode. Due to the narrow light spectrum, thermalization and transmission losses in PPCs can be significantly reduced and very high light-to-electricity conversion efficiencies up to 68.9 % have been shown [1]. An optical power supply can be an elegant solution to power medical implants from outside the body.…”

Section: Introductionmentioning

confidence: 99%

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4-Junction GaAs Based Thin Film Photonic Power Converter with Back Surface Reflector for Medical Applications

Schauerte

Höhn

Wierzkowski

et al. 2021

2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)

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Energy supply of medical implants is a challenging task that poses requirements regarding electrical performance, safety, mechanical dimensions, biological compatibility and ideally compatibility with diagnostic methods such as magnetic resonance imaging. In this paper we report about photovoltaic cells that are optimized to power medical implants optically. We demonstrate 4junction thin film photonic power converters (PPCs) with integrated back reflector designed to operate under monochromatic near-infrared light with a wavelength of 855 nm. The influence of the incident laser wavelength and spectral sensitivity are investigated under 809 nm and 855 nm laser light. Measurements under 855 nm light at a temperature of 25 °C suggest almost perfect current match. However, already at an operating temperature of 40 °C, as expected for operation of the implant inside the body, current mismatch becomes apparent. The impact of spectral sensitivity and current mismatch on the shape of the I-V curve is discussed based on measurements at a detuned wavelength of 809 nm. Furthermore, the effect of a gold back surface reflector on cell performance is examined and a lower sensitivity on current mismatch conditions due to the mirror is found. Despite the dependence of the device performance on temperature and wavelength, the maximum power point voltage remains well above 3.3 V under all relevant operating conditions, which makes these PPCs well suited to drive smart implant electronics without the need for voltage upconversion.

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Section: A Measurements Under 809 Nm Lightsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

4-Junction GaAs Based Thin Film Photonic Power Converter with Back Surface Reflector for Medical Applications

Schauerte

Höhn

Wierzkowski

et al. 2021

2021 IEEE 48th Photovoltaic Specialists Conference (PVSC)

Self Cite

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show abstract

“…From our proposed architectures, the 3C‐SiC hLPC shows a remarkable efficiency between 10 and 100 W cm −2 , which could be considered the typical operating range of LPCs. This hLPC, optimized at 10 W cm −2 , achieves a 80.0% efficiency, improving the current record of Helmers et al [ 21 ] by 11.1%, and increases to 81.1% at 100 W cm −2 , exceeding by 9.7% the efficiency reported by the Outes et al [ 22 ] simulated vLPC. At higher P in values, like other horizontal LPCs, it suffers a decrease in efficiency due to growing series resistance losses and Auger recombination.…”

Section: Resultssupporting

confidence: 58%

“…The state‐of‐the‐art LPCs shown here are GaAs or AlGaAs/GaAs based, which is the current standard technology. Helmers et al [ 21 ] have achieved a remarkable efficiency of 68.9% at 11.4 W cm −2 with the implantation of an optical cavity that minimizes transmission and thermalization losses. This is the highest efficiency achieved by an experimental LPC, and the largest for P in values below 100 W cm −2 .…”

Section: Resultsmentioning

confidence: 99%

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Laser Power Converter Architectures Based on 3C‐SiC with Efficiencies >80%

et al. 2022

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High power laser transmission technology is based on energy transfer through a monochromatic laser onto a photovoltaic receiver avoiding the limitations of conventional wiring. Current technology, headed by GaAs‐based devices, faces two limitations: the intrinsic entropic losses and the degradation at high input power densities due to ohmic losses. Two novel laser power converters focused on overcoming these limitations are proposed. 3C‐SiC is used as base material because of its high bandgap (2.36 eV) and its excellent crystallographic properties in order to reduce the entropic losses. Also, the current decreases due to the inherent flux reduction of high energy photons. To minimize ohmic losses, a recently proposed vertical architecture is explored, which can significantly reduce series resistance around two orders of magnitude (≈10−5 Ω cm2). Furthermore, 3C‐SiC is also implemented in a conventional horizontal architecture to show the advantage of increasing the energy gap to reduce the ohmic losses. The two laser power converters obtain efficiencies above the state‐of‐the‐art (87.4% at 3000 W cm−2 for the vertical architecture and 81.1% at 100 W cm−2 for the horizontal architecture) Taking this into account, the new devices open a new route for ultrahigh efficiency remote powered systems.

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Fabrication, Functionalities and Applications of Transparent Wood: A Review

Xin

Wang

et al. 2023

Adv Funct Materials

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Transparent wood (TW)‐based materials have increasingly become the focus of researchers worldwide owing to their superior physico‐chemical‐optical properties, sustainable nature, as well as the fact that they are highly accommodating frameworks that can act as building blocks to readily explore a vast range of potential functionalities, holding great potential to displace glass and plastics in their various respective applications. The integration of multiple functionalities into TW has been undertaken to fulfill the demands of prospective sophisticated applications through the utilization of functional fillers or coatings. Herein, the up‐to‐date foundational developments and reports concerning emergent TW composites and coatings from a perspective of fabrication‐functionality‐application are comprehensively summarized, with a particular focus on seven specific functionalities; i) solar control; ii) chromically‐responsive, iii) electrically‐conductive, iv) shape‐memory active; v) flame‐retardant; vi) electromagnetic interference shielding; and vii) aesthetics. The potential applications of TW with these functionalities are also discussed. Finally, the current challenge with TW is addressed, as well as the future developments required for eventual real‐world application.

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68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance

Cited by 38 publications

References 27 publications

4-Junction GaAs Based Thin Film Photonic Power Converter with Back Surface Reflector for Medical Applications

4-Junction GaAs Based Thin Film Photonic Power Converter with Back Surface Reflector for Medical Applications

Laser Power Converter Architectures Based on 3C‐SiC with Efficiencies >80%

Fabrication, Functionalities and Applications of Transparent Wood: A Review

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