Size‐Tunable Photothermal Germanium Nanocrystals

• Published in: Angewandte Chemie International Edition Vol. 56; no. 22; pp. 6329 - 6334
• Main Authors: Sun, Wei, Zhong, Grace, Kübel, Christian, Jelle, Abdinoor A., Qian, Chenxi, Wang, Lu, Ebrahimi, Manuchehr, Reyes, Laura M., Helmy, Amr S., Ozin, Geoffrey A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 22.05.2017
• Edition: International ed. in English
• Subjects: Batteries; Catalysis; Crystals; Dehydration; Desalination; Disproportionation; Electronic equipment; Energy gap; Germanium; germanium monoxide; Lithium; Lithium ions; nanochemistry; Nanocrystals; Nanomaterials; Nanotechnology; photothermal effect; Raman spectroscopy; Silicon; solid-state synthesis; Spectroscopy; germanium monoxide; solid-state synthesis; photothermal effect; nanochemistry; nanocrystals
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201701321

Germanium nanocrystals (ncGe) have not received as much attention as silicon nanocrystals (ncSi). However, Ge has demonstrated superiority over Si nanomaterials in some applications. Examples include, high charge–discharge rate lithium‐ion batteries, small band‐gap opto‐electronic devices, and photo‐therapeutics. When stabilized in an oxide matrix (ncGe/GeOx), its high charge‐retention has enabled non‐volatile memories. It has also found utility as a high‐capacity anode material for Li‐ion batteries with impressive stability. Herein, we report an organic‐free synthesis of size‐controlled ncGe in a GeOx matrix as well as freestanding ncGe, via the thermal disproportionation of GeO prepared from thermally induced dehydration of Ge(OH)2. The photothermal effect of ncGe, quantified by Raman spectroscopy, is found to be size dependent and superior to ncSi. This advance suggests applications of ncGe in photothermal therapy, desalination, and catalysis. White light, white heat: A soft‐chemistry synthesis of GeO, based on the thermally induced dehydration of Ge(OH)2, enables its thermal disproportionation to give size‐controlled germanium nanocrystals (ncGe), which exhibit a pronounced size‐dependent photothermal effect, superior to that of silicon nanocrystals (ncSi).