Publicação
Solution-processed oxide thin films for electrochromic devices application
| Resumo: | Electrochromic (EC) devices allow to reversibly change their colour when a small voltage is applied and can be used in buildings, satellites or airplanes. NiO and WO3 are two promising electrochromic materials with great electrochromic properties. Once NiO is a cathodic and WO3 is an anodic EC material, it is beneficial to combine them in a complementary effect electro- chromic window. The production techniques of both NiO and WO3 devices have been evolving but are still expensive due to typical vacuum-based and high pressure production processes. Therefore, it is highly important to find new low-cost methods that can allow to produce EC films with good electrochromic properties. Solution combustion synthesis (SCS) is a simple low-cost method and a possible alternative. In this work, NiO and WO3 films were produced through SCS and deposited by spin coating. Once the film production was optimized, they were structurally, optically and electrochemically characterized. NiO and WO3 films presented a thickness of (195±6) nm and of (53±3) nm, respectively. Both films did not present long range order and only NiO films presented a porous structure. WO3 and NiO films presented an iden- tical optical modulation of 20%. Cyclic voltammetry measures revealed two oxidation and two reduction peaks for NiO films and only one reduction peak for WO3. Finally, NiO and WO3 films presented low operating voltages and coloration/bleaching times of (21±1)/(8±1) s and (45±7)/ (46±4) s, respectively. The films exhibited a promising reversible electrochromic be- haviour which can be employed in complementary effect electrochromic windows after process optimization. |
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| Autores principais: | Viegas, Jaime Silveira |
| Assunto: | Electrochromic Nickel Oxide Tungsten Oxide Spin Coating Solution Combustion Synthesis |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | Electrochromic (EC) devices allow to reversibly change their colour when a small voltage is applied and can be used in buildings, satellites or airplanes. NiO and WO3 are two promising electrochromic materials with great electrochromic properties. Once NiO is a cathodic and WO3 is an anodic EC material, it is beneficial to combine them in a complementary effect electro- chromic window. The production techniques of both NiO and WO3 devices have been evolving but are still expensive due to typical vacuum-based and high pressure production processes. Therefore, it is highly important to find new low-cost methods that can allow to produce EC films with good electrochromic properties. Solution combustion synthesis (SCS) is a simple low-cost method and a possible alternative. In this work, NiO and WO3 films were produced through SCS and deposited by spin coating. Once the film production was optimized, they were structurally, optically and electrochemically characterized. NiO and WO3 films presented a thickness of (195±6) nm and of (53±3) nm, respectively. Both films did not present long range order and only NiO films presented a porous structure. WO3 and NiO films presented an iden- tical optical modulation of 20%. Cyclic voltammetry measures revealed two oxidation and two reduction peaks for NiO films and only one reduction peak for WO3. Finally, NiO and WO3 films presented low operating voltages and coloration/bleaching times of (21±1)/(8±1) s and (45±7)/ (46±4) s, respectively. The films exhibited a promising reversible electrochromic be- haviour which can be employed in complementary effect electrochromic windows after process optimization. |
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