Phase-Selective Synthesis of Indium Hydroxide, Oxyhydroxide and Oxide Nanocrystals Using a One-Step Hydrothermal Process and Their Luminescence Properties

Pure cubic In 2 O 3 , orthorhombic InOOH and cubic In(OH) 3 nanocrystals were separately synthesized via a one-pot hydrothermal route at low temperature by simply regulating the amount of water in the quaternary system H 2 O–DEG–In(NO 3 ) 3 –CO(NH 2 ) 2 . The use of diethylene glycol (DEG) is a crucial factor for the formation of In 2 O 3 phase. Detailed formation mechanisms for the In 2 O 3 phase have been proposed on the hydrolysis of indium alkoxide complexes at elevated temperature in DEG solutions. The postannealing-produced In 2 O 3 show a blue emission under UV excitation due to the oxygen vacancies. In our work, the process flow of In 2 O 3 synthesis was shortened.