Self-dispersible graphene quantum dots in ethylene glycol for direct absorption-based medium-temperature solar-thermal harvesting

Abstract

Self-dispersible graphene quantum dots in ethylene glycol enable stable nanofluidic solar-thermal energy harvesting at medium temperatures.

Coal-derived graphene quantum dots with a Mn2+/Mn7+ nanosensor for selective detection of glutathione by a fluorescence switch-off–on assay

“…GQDs are ideal biosensors because of their enticing superiorities and promising utilization in various fields like drug delivery, 17 sensing, 18 fluorescent probes, photocatalysis, 19,20 energy conversion, 21 bioimaging, and biotherapy. 22 GQDs can be synthesized using different chemical precursors such as pyrene, 23 citric acid, 24 ethylene diamine tetraacetic acid (EDTA), 25 thiourea, 26 ammonium citrate, 27 graphite, 28 etc. However, attempts to replace the chemical precursors have been made, owing to their perceived toxicity.…”

“…GQDs can be synthesized using different chemical precursors such as pyrene, 23 citric acid, 24 ethylene diamine tetraacetic acid (EDTA), 25 thiourea, 26 ammonium citrate, 27 graphite, 28 etc. However, attempts to replace the chemical precursors have been made, owing to their perceived toxicity.…”

Solid–Liquid Phase Change Composite Materials for Direct Solar–Thermal Energy Harvesting and Storage

“…(b) Dispersion of rGO and GQDs within polar PCMs by virtue of hydrogen bonding between abundant oxygen-containing groups and PCM molecules. Reproduced with permission from refs and . Copyright 2019 and 2020 Royal Society of Chemistry.…”

“…In comparison, graphene quantum dots (GQDs) decorated with temperature-tolerant hydroxyl groups could retain their stable dispersion at 180 °C for 7 days and realize stable STES at 170 °C because their smaller particle size reduces interparticle attraction and favors random Brownian motion in the storage medium (Figure 2b). 21 Transforming planar GO sheets into crumpled rGO particles can avoid large-area direct surface contact between neighboring GO sheets and thus minimize the aggregation driving force. Such strategy offers a route to prepare self-dispersible solar absorbers without resorting to time-consuming complicated surface modification engineering, which usually fails because surface ligands tend to desorb and degrade when the composites are subject to long-term concentrated solar irradiation.…”

“…With increasing heating temperatures, the rGO particles are further reduced and the amount of oxygen-containing functional groups decreases, which in turn weakens the hydrogen bonding interaction and loses their original homogeneous dispersion at 150 °C. In comparison, graphene quantum dots (GQDs) decorated with temperature-tolerant hydroxyl groups could retain their stable dispersion at 180 °C for 7 days and realize stable STES at 170 °C because their smaller particle size reduces interparticle attraction and favors random Brownian motion in the storage medium (Figure b) …”