In particular he showed that light consists of photons with the energy h*f each. H stands for the Planck constant and f for the frequency.

Sorry, I cannot resist to give more information, to slightly correct the above sentence (which is not 100% accurate :p). I hope you don't mind.

Theoretically, Einstein introduced the idea that light was made of particles between 1905 and 1916, and this was experimentally confirmed in 1923 through the observation of the Compton effect. This is why he had to wait for the Nobel prize. Note also that the name photons only appeared for the first time in 1926 (given by Lewis). The genius of Einstein with the photoelectric effect lies in proposing the idea that electromagnetic radiation is quantized.

PS: do not hesitate to come and say hi on the #steemSTEM channel.

PS2: very nice series of posts on the myths/facts stuff.