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A new design for an energy-harvesting electrochromic window (EH-ECW) based on the fusion of two technologies, organic electrochromic windows and dye-sensitized solar cells (DSSCs), is presented. Unlike other power-generating smart windows, such as photoelectrochromic devices that are passive and only contain two states (i.e., a closed-circuit colored state and an open-circuit bleaching state), EH-ECW allows active tuning of the transmittance by varying the applied potential and it functions as a photovoltaic cell based on a DSSC. The resulting device demonstrates a fast switching rate of 1 s in both the bleaching and coloring processes through the use of an electrochromic polymer as a counter electrode layer. To increase the transmittance of the device, a cobalt redox couple and a light-colored, yet efficient, organic dye are used. The organic dye contains a polymeric structure that contributes to the high cyclic stability. The device exhibits a power conversion efficiency (PCE) of 4.5% (100 mW cm-2) under AM 1.5 irradiation, a change in transmittance of 34% upon applied potential, and shows only 3% degradation in the PCE after 5000 cycles. [ABSTRACT FROM AUTHOR]

A new design for an energy-harvesting electrochromic window (EH-ECW) based on the fusion of two technologies, organic electrochromic windows and dye-sensitized solar cells (DSSCs), is presented. Unlike other power-generating smart windows, such as photoelectrochromic devices that are passive and only contain two states (i.e., a closed-circuit colored state and an open-circuit bleaching state), EH-ECW allows active tuning of the transmittance by varying the applied potential and it functions as a photovoltaic cell based on a DSSC. The resulting device demonstrates a fast switching rate of 1 s in both the bleaching and coloring processes through the use of an electrochromic polymer as a counter electrode layer. To increase the transmittance of the device, a cobalt redox couple and a light-colored, yet efficient, organic dye are used. The organic dye contains a polymeric structure that contributes to the high cyclic stability. The device exhibits a power conversion efficiency (PCE) of 4.5% (100 mW cm-2) under AM 1.5 irradiation, a change in transmittance of 34% upon applied potential, and shows only 3% degradation in the PCE after 5000 cycles. [ABSTRACT FROM AUTHOR]

To mitigate global warming to the most ambitious targets, it is necessary to remove CO 2 from the atmosphere and reduce fossil fuels use. The electrochemical conversion of CO 2 to ethylene (C 2 H 4 ) as a basic chemical is a promising technology that meets both requirements; however, its life cycle CO 2 emissions remain inconclusive because of varying assumptions in the performance indices. This study aimed to set benchmarks for the four most sensitive indices to achieve -0.5 t-CO 2 /t-C 2 H 4 by calculating net greenhouse gas (GHG) emissions through a prospective life cycle assessment of a model system including CO 2 capture, CO 2 enrichment, electrochemical conversion, CO 2 recycling, and cryogenic separation. As a result, the electrochemical conversion process was the hotspot of life cycle emissions, and representative benchmarks were determined as follows: cell voltage, 3.5 V; C 2 H 4 Faraday efficiency, 70 %; conversion rate, 20 %; and electrochemical CO 2 recycling energy, 2.2 GJ/t-CO 2 . The gaps between the benchmarks and current top data of cell voltage and Faraday efficiency were <10 %, and suppressing the performance degradation for up to one year was found to be a critical requirement. These results can direct research towards the development of a year-round stable system, rather than further improving the performance indices., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)