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Item type:Publication, Access status: without files , Universal and scalable fabrication of plasmonic nanocrystals for ultrasensitive SERS(ACS, 2026-05-10); ; ; 17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , 2D photonic crystal emitter at 1,400°C for thermophotovoltaic energy harvesting(Elsevier, 2025-10-15); ; ; ; Spectrally selective emitters that endure extreme temperatures (exceeding 1,000°C) are vital for thermophotovoltaic energy harvesting. Here, we report a 2D photonic crystal emitter composed of yttria-stabilized zirconia particles on a tungsten mirror, fabricated through a simple and scalable self-assembly process. The emitter demonstrates spectral stability for 2 h and structural stability for 14 h at 1,400°C under high vacuum, with degradation attributed to zirconium nitridation, which is avoided under Ar or forming gas atmospheres. Long-term durability is demonstrated over 6 months and 200 thermal cycles at 1,050°C, effectively mitigating tungsten oxidation. The emitter achieves 52% spectral efficiency for a 0.72 eV photovoltaic band gap. This work offers perspectives on designing and implementing spectrally selective emitters that remain stable at high temperatures and resilient in harsh environments, representing a significant step forward in developing robust thermophotovoltaic energy-harvesting systems.Publicationtype: Journal Article21 22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Iridium-based selective emitters for thermophotovoltaic applications(Elsevier, 2023-10-12); ; ; ; Raudsepp, RagleThe long-term operation of refractory-metal-based metamaterials is crucial for applications such as thermophotovoltaics. The metamaterials based on refractory metals like W, Mo, Ta, Nb, and Re fail primarily by oxidation. Here, the use of the noble metal Ir is proposed, which is stable to oxidation and has optical properties comparable to gold. The thermal endurance of Ir in a 3-layer-system, consisting of HfO2/Ir/HfO2, by performing annealing experiments up to 1240 °C in a pressure range from 2 × 10−6 mbar to 1 bar, is demonstrated. The Ir layer shows no oxidation in a vacuum and inert gas atmosphere. At temperatures above 1100 °C, the Ir layer starts to agglomerate due to the degradation of the confining HfO2 layers. An in situ X-ray diffraction experimental comparison between 1D multilayered Ir/HfO2 and W/HfO2 selective emitters annealed at 1000 °C, 2 × 10−6 mbar, over 100 h, confirms oxidation stability of Ir while W multilayers gradually disappear. The results of this work show that W-based metamaterials are not long-term stable even at 1000 °C. However, the oxidation resistance of Ir can be leveraged for refractory plasmonic metamaterials, such as selective emitters in thermophotovoltaic systems with strong suppression of long wavelength radiation.Publicationtype: Journal ArticleScopus© Citations 6 29 89 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Material systems for metamaterial based selective thermal emitters(META Conference, 2023-07); ; ; High temperature stable thin film multilayers of metal and dielectric materials are important as selective emitters for thermophotovoltaics (TPV). We will present structured material systems from W, Ir, and HfO2 and discuss degradation mechanisms.Publicationtype: Conference Paper43