Figure 1 shows the UV absorption of synthesized AgNPs, which is capped with phospholipids membrane.
The fresh synthesized silver nanoparticles have a yellow colour which has higher absorption than the capped AgNPs.
But they have a short lifetime and their colour changes to dark yellow, and then black suspension and slowly turn to macro particle and settle.
AgNPs have a localized peak at 405 nm and their colour shift to darker by adding lecithin which causes their absorption to reduce.
This is because of the lack of absorption for lecithin suspension at this position