EF values calculated at ten different peaks of MB (10⁻⁷ M) taking Ag NPl4, Ag–Au2, Ag–Au5, and Ag–Au12 for SERS studies.

Substrate used	Enhancement factor (EF) values at a peak position for MB (10−7 M)
	1624 cm−1	1437 cm−1	1395 cm−1	1302 cm−1	1154 cm−1	1070 cm−1	1037 cm−1	772 cm−1	501 cm−1	445 cm−1
Ag NPl4	1.3 × 106	4.8 × 104	2.2 × 104	No detect	No detect	No detect	3.2 × 10	No detect	No detect	No detect
Ag–Au2	8.3 × 106	2.5 × 105	2 × 104	6.8 × 104	8 × 104	6.4 × 104	1 × 105	6 × 104	5.4 × 104	9.2 × 104
Ag–Au5	1.0 × 107	2.2 × 105	2.7 × 104	8.2 × 104	9.2 × 104	7.8 × 105	6.8 × 104	7.4 × 104	6 × 104	8.6 × 104
Ag–Au12	1.2 × 107	2.2 × 105	2.4 × 105	7.2 × 104	7.8 × 104	9.2 × 104	6.4 × 104	8.2 × 104	7.8 × 104	1.1 × 105