Publicação
NIR-emitting electrochromic windows for cold climate region buildings
| Resumo: | Electrochromic devices (ECDs) comprising visible/near-infrared (NIR) transparent amorphous indium zinc oxide (a-IZO) outermost layers and novel NIR-emitting electrolytes are proposed for smart windows of buildings in cold climate regions. The electrolytes are composed of a di-urethane cross-linked poly(oxyethylene)(POE)/siloxane hybrid matrix (d-Ut(600), 600 is the average molecular weight of the POE chains in gmol<sup>−1</sup>), 1-butyl-3-methylimidazolium chloride ionic liquid, and the Er(tta)<inf>3</inf>(H<inf>2</inf>O)<inf>2</inf> complex (tta<sup>−</sup> is 2-thenoyltrifluoracetonate). The electrolytes, synthesized by sol-gel route, were obtained as transparent, flexible, and hydrophilic monoliths with nanoscale surface roughness, exhibiting emission in the NIR wavelength region. The first electro-optical tests, performed in 2019, with an archetypal ECD including amorphous tungsten oxide and crystalline nickel oxide as EC layers, a-IZO as outermost layers, and d-Ut(600)<inf>400</inf>Er(tta)<inf>3</inf>(H<inf>2</inf>O)<inf>2</inf>[Bmim]Cl (400 is the molar ratio of oxyethylene units/Er<sup>3+</sup> ion) as the electrolyte, demonstrated rather low coloration efficiency (CE<inf>in</inf>/CE<inf>out</inf>) values of −4/+6 cm<sup>2</sup> C<sup>−1</sup> at 555 nm. After 3 years of storage at rest in the dark and at room temperature, the same device demonstrates a huge performance enhancement, leading to CE<inf>in</inf>/CE<inf>out</inf> values about two orders of magnitude higher, apart from higher optical density, and improved cycling stability. In addition, this device offers a bright hot, and semi-bright warm dual modulation operation suitable for smart windows of skylights, roof lights, upper windows, inclined glazing, and privacy glazing of buildings located in cold climate regions. |
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| Autores principais: | Pinheiro, Daniela |
| Outros Autores: | Fernandes, Mariana; Pereira, Rui Francisco Gonçalves Pinto Fernandes; Pereira, Sónia; Correia, Sandra F.H.; Silva, Maria Manuela; Fortunato, Elvira; Ferreira, Rute A.S.; Gonçalves, Maria; de Zea Bermudez, Verónica |
| Assunto: | electrochromic windows erbium complex NIR emitting electrolytes visible/NIR transparent conducting oxides zero-energy buildings |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Electrochromic devices (ECDs) comprising visible/near-infrared (NIR) transparent amorphous indium zinc oxide (a-IZO) outermost layers and novel NIR-emitting electrolytes are proposed for smart windows of buildings in cold climate regions. The electrolytes are composed of a di-urethane cross-linked poly(oxyethylene)(POE)/siloxane hybrid matrix (d-Ut(600), 600 is the average molecular weight of the POE chains in gmol<sup>−1</sup>), 1-butyl-3-methylimidazolium chloride ionic liquid, and the Er(tta)<inf>3</inf>(H<inf>2</inf>O)<inf>2</inf> complex (tta<sup>−</sup> is 2-thenoyltrifluoracetonate). The electrolytes, synthesized by sol-gel route, were obtained as transparent, flexible, and hydrophilic monoliths with nanoscale surface roughness, exhibiting emission in the NIR wavelength region. The first electro-optical tests, performed in 2019, with an archetypal ECD including amorphous tungsten oxide and crystalline nickel oxide as EC layers, a-IZO as outermost layers, and d-Ut(600)<inf>400</inf>Er(tta)<inf>3</inf>(H<inf>2</inf>O)<inf>2</inf>[Bmim]Cl (400 is the molar ratio of oxyethylene units/Er<sup>3+</sup> ion) as the electrolyte, demonstrated rather low coloration efficiency (CE<inf>in</inf>/CE<inf>out</inf>) values of −4/+6 cm<sup>2</sup> C<sup>−1</sup> at 555 nm. After 3 years of storage at rest in the dark and at room temperature, the same device demonstrates a huge performance enhancement, leading to CE<inf>in</inf>/CE<inf>out</inf> values about two orders of magnitude higher, apart from higher optical density, and improved cycling stability. In addition, this device offers a bright hot, and semi-bright warm dual modulation operation suitable for smart windows of skylights, roof lights, upper windows, inclined glazing, and privacy glazing of buildings located in cold climate regions. |
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