The peaks of absorption spectra on AgNPs depend on the sizes of nanoparticles. It looks like your nanomaterials are very big though.

Please see the following link for the optical properties of AgNPs with various sizes.

https://nanocomposix.com/pages/silver-nanoparticles-optical-properties

Dear Marwah Alnuaimi ,

Please check my answer to that previous question:

https://www.researchgate.net/post/Need_some_clarification_on_Surface_plasmon_SPP_SPR_and_relation_among_dipoles_SPP_and_SPR

There is a keyword you should check to understand your spectra: plasmon, a resonant excitation of an electron sea in the material typical of a number of mtals and affecting their optical behaviour. In a simplified picture, the ocean of free electrons in a nanoparticle absorbs (as a whole) photons of a given wavelength and get excited in a collective (that is "plasma") state. Such wavelength depends primarily on the material type and on the nanoparticle size/shape, but there may be an influence also from the material hosting the nanoparticles, for example the liquid in which they are dispersed (Mie Theory). I'm afraid that without an at least minimal knowledge of such things, it will be difficult to follow the optical results of any experiments like yours.