Enhancing passive radiative cooling properties of flexible CIGS solar cells for space applications using single layer silicon oxycarbonitride films

Banik, Udayan; Sasaki, Kaname; Reininghaus, Nies; Gehrke, Kai; Vehse, Martin; Sznajder, Maciej; Sproewitz, Tom; Agert, Carsten

doi:10.1016/j.solmat.2020.110456

Cited by 30 publications

(18 citation statements)

References 20 publications

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“…Daytime radiative cooling has recently attracted intense interest because it can dissipate terrestrial heat to deep space and yield a below-ambient temperature without any external energy input, even under direct sunlight. − The unique nature of radiative cooling has enabled promising applications in various fields such as energy-efficient buildings, − artificial wood, solar cells, − water condensation, − and thermoelectric devices as well as wearable and flexible fabrics . In most of these application scenarios, daytime radiative cooling (DRC) is urgently needed rather than nocturnal cooling, yet it is also more challenging since solar radiation generally far exceeds thermal emission during the day.…”

Section: Introductionmentioning

confidence: 99%

Flexible Daytime Radiative Cooling Enhanced by Enabling Three-Phase Composites with Scattering Interfaces between Silica Microspheres and Hierarchical Porous Coatings

Wang

Dou

et al. 2021

ACS Appl. Mater. Interfaces

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Daytime radiative cooling has attracted considerable attention recently due to its tremendous potential for passively exploiting the coldness of deep-sky as clean and renewable energy. Many advanced materials with novel photonic micro-nanostructures have already been developed to enable highly efficient daytime radiative coolers, among which the flexible hierarchical porous coatings (HPCs) are a more distinguished category. However, it is still hard to precisely control the size distribution of the randomized pores within the HPCs, usually resulting in a deficient solar reflection at the near-infrared optical regime under diverse fabrication conditions of the coatings.We report here a three-phase (i.e., air pore-phase, microsphere-phase and polymerphase) self-assembled hybrid porous composite coating which dramatically increases the average solar reflectance and yields a remarkable temperature drop of ~10℃ and ~30℃ compared to the ambient circumstance and black paint, respectively, according to the rooftop measurements. Mie theory and Monte Carlo simulations reveal the origin of the low reflectivity of as-prepared two-phase porous HPCs, and the optical cooling improvement of the three-phase porous composite coatings is attributed to the newly generated interfaces possessing the high scattering efficiency between the hierarchical pores and silica microspheres hybridized with appropriate mass fractions. As a result, the hybrid porous composite approach enhances the whole performance of the coatings, which provides a promising alternative to the flexible daytime radiative cooler.

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Section: Introductionmentioning

confidence: 99%

Flexible Daytime Radiative Cooling Enhanced by Enabling Three-Phase Composites with Scattering Interfaces between Silica Microspheres and Hierarchical Porous Coatings

Wang

Dou

et al. 2021

ACS Appl. Mater. Interfaces

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“…If a bare cell is set as the comparison object rather than the one with a glass cover, a considerable temperature reduction is always available in various studies. [17,18,33] In addition, if a solar cell operates in an extraterrestrial environment, such as in space applications, [34] or is exposed with concentrated solar radiation, [35,36] higher heat input and lower thermal convection would also promote the benefits from an additional radiative cooling coating.…”

Section: Discussionmentioning

confidence: 99%

Investigating the Effect of Radiative Cooling on the Operating Temperature of Photovoltaic Modules

Ahmed

2021

Solar RRL

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Due to the linear decrease in power conversion efficiency with temperature, effective methods for the thermal management of silicon photovoltaics (PV) are urgently needed. Recently, the emergence of radiative cooling technologies has breathed new life into this topic. Some previous studies claimed the value of an additional radiative cooling coating on silicon solar cells, whereas quantitative analysis based on comprehensive experiments and modeling is still not available in literature to give an explicit conclusion. After developing the coupling electrical–thermal model for simulating various cases and conducting field experimental tests, herein, it is aimed to clarify the effect of radiative cooling on the temperature of normally installed PV modules and influence of factors such as thermal convection and thermal emissivity. Results show that the increased thermal emissivity results in only an average temperature drop of less than 1.0 °C, whereas the ventilation conditions have an impact of over 10 °C. The simulation study also demonstrates that a limit of around 2.0 °C in temperature reduction is all the value of an additional radiative cooling coating on PV modules. To make an additional radiative cooling coating on existing PV panels cost effective, the work suggests developing multifunctional coatings in the future.

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“…In this paper, we demonstrate for the first time a spectrally selective planar polymer emitter derived from polysilazane which was used in combination with a highly reflective 230 nm thick silver layer on an aluminum substrate to create a PDRC structure. Polysilazanes are silicon-based precursor polymers with alternating silicon and nitrogen atoms in its backbone and have been an area of intense research since the 1960s. , Substantial efforts were made to understand the optical properties of PSZ coatings. − Recently we identified and demonstrated the high emissivity, optical transparency, flexibility, and protective properties against mechanical abrasion of silicon oxycarbonitride (SiCNO) emitter coating derived from PSZ on thin-film solar cells for space applications. , PSZ-derived coatings show outstanding mechanical sturdiness, hydrophobicity, and chemical stability and have strong adhesive properties to most substrates even as cross-linked polymers. − These desirable properties of the PSZ polymer coating make it an appealing material to be used as an emitter for PDRC applications. The thin polymer emitter layer, fabricated from a polysilazane (PSZ) precursor, is easy to apply and has molecular vibrations that overlap with the 8–13 μm atmospheric transmission window exceedingly well.…”

Section: Introductionmentioning

confidence: 99%

Efficient Thin Polymer Coating as a Selective Thermal Emitter for Passive Daytime Radiative Cooling

Banik¹,

Agrawal²,

Meddeb³

et al. 2021

ACS Appl. Mater. Interfaces

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Radiative cooling to subambient temperatures can be efficiently achieved through spectrally selective emission, which until now has only been realized by using complex nanoengineered structures. Here, a simple dip-coated planar polymer emitter derived from polysilazane, which exhibits strong selective emissivity in the atmospheric transparency window of 8–13 μm, is demonstrated. The 5 μm thin silicon oxycarbonitride coating has an emissivity of 0.86 in this spectral range because of alignment of the frequencies of bond vibrations arising from the polymer. Furthermore, atmospheric heat absorption is suppressed due to its low emissivity outside the atmospheric transparency window. The reported structure with the highly transparent polymer and underlying silver mirror reflects 97% of the incoming solar irradiation. A temperature reduction of 6.8 °C below ambient temperature was achieved by the structure under direct sunlight, yielding a cooling power of 93.7 W m–2. The structural simplicity, durability, easy applicability, and high selectivity make polysilazane a unique emitter for efficient prospective passive daytime radiative cooling structures.

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Enhancing passive radiative cooling properties of flexible CIGS solar cells for space applications using single layer silicon oxycarbonitride films

Cited by 30 publications

References 20 publications

Flexible Daytime Radiative Cooling Enhanced by Enabling Three-Phase Composites with Scattering Interfaces between Silica Microspheres and Hierarchical Porous Coatings

Flexible Daytime Radiative Cooling Enhanced by Enabling Three-Phase Composites with Scattering Interfaces between Silica Microspheres and Hierarchical Porous Coatings

Investigating the Effect of Radiative Cooling on the Operating Temperature of Photovoltaic Modules

Efficient Thin Polymer Coating as a Selective Thermal Emitter for Passive Daytime Radiative Cooling

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