Fig. 2

FE-SEM images of AgNW films with different deposition numbers and prepared by different coating methods. a–d The cross-AgNW films with different surface concentrations of AgNWs. e–h The drop-casted AgNW films with corresponding AgNW concentrations. Surface density of AgNWs on Au substrate: a, e 4.7 μg/cm2, b, f 5.9 μg/cm2, c, g 8.3 μg/cm2, and d, h 10.6 μg/cm2