Both my old (Beithaupt) and my new textbook (England etc) for AQA AS Physics seem to like to do particles in the opposite order from tradition. The trouble with this is you are talking about photons before you’ve explained where the idea comes from. I’m afraid I’m traditional and like to teach it from a historical point of view. To that end I follow this timeline:

Particles Early Timeline

When I get towards the photoelectric effect I follow the history as laid out by Klassen:

Klassen_on_the_Photoelectric_Effect

I illustrate the history with an apparatus diagram from Von Lenard’s Nobel Lecture:

Lenard

And the graph that Millikan produced when trying to disprove it, from his Nobel Lecture:

millikan_nobel-lecture

And although not strictly in the A level, having introduced De Broglie, I like to go through the Bohr atom as well:

Hydrogen and Bohr