I am using a data set pictured below to generate this figure using ggplot. I am attempting to add a trend line to the plot. I have tried multiple times to add the line in different methods and have not been able to figure it out. I appreciate any help you are able to provide.

I have plotted the variation of concentration with time for a particular chemical. I needed to show the expotential trendline for the data. The data was filtered fom a larger dataset. I used the below code to obtain the trendlines but I am unable to add the equations and r2 value. any help will be appreciated.