Fig. 3

Optical features of Mn-N-CNSs: a UV–visible absorption of the Mn-N-CNSs, inset pictures show the Mn-N-CNSs under natural light and UV light, b PL emission and excitation of the Mn-N-CNSs, c The PL emission of the Mn-N-CNSs with excitation wavelengths from 320 to 520 nm in 20 nm increments, d The normalized PL emission of the Mn-N-CNSs with excitation wavelengths from 320 to 520 nm in 20 nm increments