D1.4 - Photovoltaic Cells with Increased Voltage Output for Optical Power Supply of Sensor Electronics

Helmers, Henning; Wagner, Lukas; Garza, C.; Reichmuth, S. Kasimir; Oliva, E.; Philipps, Simon P.; David, Laurent; Bett, Andreas W.

doi:10.5162/sensor2015/d1.4

Cited by 10 publications

(4 citation statements)

References 17 publications

(17 reference statements)

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“…However, the post-growth processing is rather more complex than in S-PVLPCs, with typically twice as many photolithography steps being required in HM-PVLPCs. 85 HM-PVLPC manufacturing consists of the definition of etched areas, metal contacts and interconnects, the formation of dielectric barriers, and the deposition of antireflection coatings. A critical step is the series interconnection between subcells.…”

Section: Manufacturing Processmentioning

confidence: 99%

Beaming power: Photovoltaic laser power converters for power-by-light

Algora

García

Delgado

et al. 2022

Joule

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Section: Manufacturing Processmentioning

confidence: 99%

Beaming power: Photovoltaic laser power converters for power-by-light

Algora

García

Delgado

et al. 2022

Joule

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“…Two strategies are available to realize this voltage compliance: either a multi-segment interconnection where the total available surface is divided into separated cells (as quarter in a pie) and connected in series; or a multi-junction approach where cells are vertically connected via tunnel junctions. Both have pros and cons 32 and the choice was made for a multi-segment approach, with an epitaxy less risky and less complex to implement.…”

Section: Methodsmentioning

confidence: 99%

An optoelectronic implantable neurostimulation platform allowing full MRI safety and optical sensing and communication

Doguet,

Garnier,

Nieuwenhuys

et al. 2024

Sci Rep

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A novel programmable implantable neurostimulation platform based on photonic power transfer has been developed for various clinical applications with the main focus of being safe to use with MRI scanners. The wires usually conveying electrical current from the neurostimulator to the electrodes are replaced by optical fibers. Photovoltaic cells at the tip of the fibers convert laser light to biphasic electrical impulses together with feedback signals with 54% efficiency. Furthermore, a biocompatible, implantable and ultra-flexible optical lead was developed including custom optical fibers. The neurostimulator platform incorporates advanced signal processing and optical physiological sensing capabilities thanks to a hermetically sealed transparent nonmetallic casing. Skin transparency also allowed the development of a high-speed optical transcutaneous communication channel. This implantable neurostimulation platform was first adapted to a vagus nerve stimulator for the treatment of epilepsy. This neurostimulator has been designed to fulfill the requirements of a class III long-term implantable medical device. It has been proven compliant with standard ISO/TS10974 for 1.5 T and 3 T MRI scanners. The device poses no related threat and patients can safely undergo MRI without specific or additional precautions. Especially, the RF induced heating near the implant remains below 2 °C whatever the MRI settings used. The main features of this unique advanced neurostimulator and its architecture are presented. Its functional performance is evaluated, and results are described with a focus on optoelectronics aspects and MRI safety.

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“…At voltages around 0 V for all I-V curves a bending is observed, so that the shortcircuit current is significantly larger than the "saturated" current between about 1 V and 4 V. This behavior can be understood as follows: As the subcells' thicknesses are optimized for current matching at λ0 = 855 nm, the multi-junction structure is current mismatched when measured under 809 nm light. More precisely, the subcells' generated photocurrent densities decrease from top to bottom due to the increased absorptance at lower wavelengths [13,14]. As the junctions are connected in series, the bottom (J4) subcell's photo current is limiting the overall current of the device.…”

Section: A Measurements Under 809 Nm Lightmentioning

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)

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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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D1.4 - Photovoltaic Cells with Increased Voltage Output for Optical Power Supply of Sensor Electronics

Cited by 10 publications

References 17 publications

Beaming power: Photovoltaic laser power converters for power-by-light

Beaming power: Photovoltaic laser power converters for power-by-light

An optoelectronic implantable neurostimulation platform allowing full MRI safety and optical sensing and communication

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

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