Time-course analysis of UV-vis data of plant extract:AgNO3 (1:1 v/v) mixture
showed accumulation of AgNPs within an hour of the reaction start time (Figure 2a).
Typically, AgNPs in colloidal solutions display maximum absorption in the λ 400-500
nm range. To capture yield of most AgNPs in this range, statistical analyses were
performed with the sum of λ 400-500 nm. A scatter plot of the time-response UV-vis data
indicated that AgNPs synthesis exhibited typical chemical kinetics. Curve fitting revealed
that AgNPs synthesis fitted an exponential model with excellent goodness-of-fit
parameters (R2=0.96, Sy.x = 0.61). AgNPs synthesis increased exponentially with a time
constant (τ) of 4.13 hours (3.17 to 5.9, 95% confidence intervals) and a half life of 2.86
hours (2.1 to 4.1, 95% confidence intervals) (Figure 2b and Figure S1). AgNPs synthesis
leveled off at 24 hours after the start of reaction with little or no increase afterwards