Optimized Optical Field Profile in Resonant-Cavity-Enhanced a-Ge:H Nanoabsorber Solar Cells for Tandem Cell Application

Steenhoff, Volker; Juilfs, Maren; Ravekes, Regina-Elisabeth; Ahrlich, Maike; Kellermann, Martin; Siepmann, Ortwin; Vehse, Martin; Agert, Carsten

doi:10.1109/jphotov.2016.2617039

Cited by 11 publications

(9 citation statements)

References 24 publications

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“…This will be referred to as the cavity “on” state. Light is confined inside the ultrathin absorber material due to nontrivial interferences. ,− The internal electric field distribution of the cavity depends on the phase shift at the interfaces and the phase shift caused by the thickness of the layers . Broadband interferences emerge in the absorber layer on Mg and enhance the overall absorption of the layer stack.…”

Section: Results and Discussionmentioning

confidence: 99%

Switchable Photocurrent Generation in an Ultrathin Resonant Cavity Solar Cell

Götz¹,

Lengert²,

Osterthun³

et al. 2020

ACS Photonics

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Fabry-Perot type resonant nanocavities allow for broadband enhancement of light absorption in ultra-thin absorber layers. By introducing a switchable mirror, these thin film structures can be used as unique optical devices enabling interesting applications with switchable absorption. We use a thin film photovoltaic layer stack based on an amorphous germanium absorber layer and combine it with a thin Mg/Pd mirror to create a switchable solar cell. In this work we demonstrate, how we can switch the light absorption and hence the photocurrent generation of the thin film solar cell by changing the refractive index of Mg, due to hydrogen absorption. Our results show, how optical resonances in the absorber can be switched "on / off" by the change of optical properties of the magnesium reflector. The multi-layer system can be switched from a light absorbing and photocurrent generating state to a transparent window state with excellent color neutrality. We emphasize our study as an important step towards the realization of switchable photovoltaic windows, which paves the way for larger scale building integrated photovoltaic applications.

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Section: Results and Discussionmentioning

confidence: 99%

Switchable Photocurrent Generation in an Ultrathin Resonant Cavity Solar Cell

Götz¹,

Lengert²,

Osterthun³

et al. 2020

ACS Photonics

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“…Detailed PECVD process parameter for the ultrathin a-Ge:H solar cell. The deposition time for the germanium layer is x = 500 or 1000 s for approximately 5 The spectrally selective reflector was prepared by direct current (DC) magnetron sputtering at room temperature with 200 mm targets. A silver target was used as the metal (M) source and a ZnO:Al target with 0.5 wt.% Al 2 O 3 doping (AZO) was used as the oxide (O) source.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, following the old mindset "thinner is better" and also out of scientific curiosity, the following question arose: how thin can the absorber layer be using light confinement structures? It turns out that, again, it can be made 100 times thinner compared to mainstream thin film technology by using ultra-high α absorber materials in combination with very strong light confinement in an optical cavity [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Structural color filters and reflectors with much better thermal stability, a higher color gamut, and lower angle sensitivity, compared to dye-based filters, have been realized [11,12]. Additionally, several groups have demonstrated the potential of cavity-enhanced PV [5,6,[13][14][15]. It quickly became clear that this new PV architecture brings about a new degree of freedom, the light confinement, with which the cell can be adapted for specific applications [16].…”

Section: Introductionmentioning

confidence: 99%

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Ultrathin Nano-Absorbers in Photovoltaics: Prospects and Innovative Applications

Götz¹,

Osterthun²,

Gehrke³

et al. 2020

Coatings

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Approaching the first terawatt of installations, photovoltaics (PV) are about to become the major source of electric power until the mid-century. The technology has proven to be long lasting and very versatile and today PV modules can be found in numerous applications. This is a great success of the entire community, but taking future growth for granted might be dangerous. Scientists have recently started to call for accelerated innovation and cost reduction. Here, we show how ultrathin absorber layers, only a few nanometers in thickness, together with strong light confinement can be used to address new applications for photovoltaics. We review the basics of this new type of solar cell and point out the requirements to the absorber layer material by optical simulation. Furthermore, we discuss innovative applications, which make use of the unique optical properties of the nano absorber solar cell architecture, such as spectrally selective PV and switchable photovoltaic windows.

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“…Previous work by our group has shown that it is possible to sandwich an ultrathin amorphous germanium absorber inside a Fabry-Perot resonant cavity [23][24][25]. The idea of the cavity, as depicted in Figure 1a, is to have light pass through the absorber multiple times by reflecting light between two interfaces, thus significantly increasing absorption.…”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional Absorbers for Solar Windows: A Simulation

Lattyak¹,

Steenhoff²,

Gehrke³

et al. 2019

Zeitschrift Für Naturforschung A

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In the future, many modern buildings may rely on solar windows for energy production. Large buildings often have glass facades that have the potential to convert sunlight to electrical power. The standard photovoltaic materials used today are bulky and not transparent, making them poor candidates for solar windows. Transition metal dichalcogenides (TMDCs) and other two-dimensional absorbers are a good alternative because of their unique properties and high transparency at the monolayer and few-layer regime. This work shows the potential for TMDC-based solar windows by simulating the transmission, quantum efficiency, current density, and colour appearance of different solar cell configurations. Different contacts were investigated, along with the influence of contact thickness, to demonstrate colour-neutral solar cells. In addition, four TMDC materials were compared: MoS2, MoSe2, WS2, and WSe2. Colour-neutral solar cells with transparencies of 35 % to 55 % are presented, where a current density of 8.33 mA/cm2 was calculated for a solar cell with a 5-nm absorbing layer of MoSe2. While there are still challenges to overcome in terms of production, our simulations show that it is possible to use TMDCs for colour-neutral solar windows and act as a guideline for further research.

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Optimized Optical Field Profile in Resonant-Cavity-Enhanced a-Ge:H Nanoabsorber Solar Cells for Tandem Cell Application

Cited by 11 publications

References 24 publications

Switchable Photocurrent Generation in an Ultrathin Resonant Cavity Solar Cell

Switchable Photocurrent Generation in an Ultrathin Resonant Cavity Solar Cell

Ultrathin Nano-Absorbers in Photovoltaics: Prospects and Innovative Applications

Two-Dimensional Absorbers for Solar Windows: A Simulation

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