Nanocrystalline Copper Selenide formation by Direct Reaction between Cu-ions and Selenosulfate

Copper selenide (Cu 3 Se 2 ) nanocrystals were successfully synthesized on glass substrate by the chemical bath deposition technique. The room temperature formation of Cu 3 Se 2 from the reaction between Cu-ions and selenosulfate in aqueous solution was investigated. The resulting precipitate from the reaction of Cu-ions and selenosulfate was initially light green (mainly a mixture of amorphous Cu 2 SO 3 .CuSO 3 and Cu(OH) 2 ) and turned to greenish brown and finally brownish (mainly Cu 3 Se 2 ). Cu 3 Se 2 was formed via the hydroxide cluster mechanism and reaction between Cu(OH) 2 and the slowly generated Se 2-ions. The Cu 3 Se 2 exhibited a disordered phase and small nanocrystals in the range of 2 to 5 nm. The formation mechanism of different phases of copper selenide by chemical bath deposition technique were explained in details.