Increasing the Solubility Limit for Tetrahedral Aluminium in ZnO:Al Nanorods by Variation in Synthesis Parameters

Table 2

Combination of the information obtained by ²⁷Al-NMR spectroscopy (tetrahedral content of 31% versus 41% for ZnO:Al nanorods obtained by solvothermal treatment at 200°C for 96 h and for 6 h with stirring, resp.) and -relaxometry (77% substitutional aluminium for the former versus 66% for the latter). Normalization to the interstitial tetrahedral fraction results in 3.4 substitutional aluminium ions for each interstitial aluminium ion for nanorods obtained by solvothermal treatment for 96 h at 200°C in contrast to only 1.9 for a solvothermal treatment for 6 h at 200°C with stirring.

96 h @ 200°C without stirring; 31% tetrahedral Al			6 h @ 200°C with stirring; 41% tetrahedral Al
23% × 31% = 7%	1	Interstitial tetrahedral Al	34% × 41% = 14%	1
77% × 31% = 24%	3.4	Substitutional tetrahedral Al	66% × 41% = 27%	1.9