Materials Chemistry

Co-harvesting Solar Energy with Ambient Heat and On-Demand Release of Thermal Energy Below 0 oC Through Visible-Light-Controlled Photochemical Phase Transitions of Azopyrazoles

Authors

Abstract

Photochemical crystal-to-liquid transition generally needs UV light as a stimulus and it is even more challenging to carry out below 0 oC. Here, we design a series of 4-alkylthioarylazopyrazoles as molecular solar thermal batteries, which show bidirectional visible-light-triggered photochemical trans-crystal ↔ cis-liquid transitions below ice point (-1 oC). Through co-harvesting visible-light energy and low-temperature ambient heat, high energy density (0.25 MJ kg-1) is achieved. Further, the rechargeable solar thermal batteries devices are fabricated, which can be charged by blue light (400 nm) at -1 oC. Then, the charged devices can release energy on demand in the form of high-temperature heat. Under green light (532 nm) irradiation, the temperature difference between the charged devices and the ice-cold surrounding is up to 13.5 oC. This study paves the way for the design of advanced molecular solar thermal batteries that store both natural sunlight and ambient heat over a wide temperature range.

Content

Thumbnail image of manuscript.pdf

Supplementary material

Thumbnail image of SI.pdf
Supporting Information
Additional Figures, Synthesis details, DFT calculation details, and characterization data
Thumbnail image of Video S1_PCLT.mp4
Video S1
photochemical phase transitions of B7-S5 at -1 °C
Thumbnail image of Video S2_cis flim.mp4
Video S2
heat release of cis-film sample on ice surface under 532 nm light irradiation
Thumbnail image of Video S3_trans flim.mp4
Video S3
heat release of trans-film sample on ice surface under 532 nm light irradiation