I hope I uderstand (subject isnt exact)
Picture below shows where I started, and where I'm now.
First 1/2 shows IR-detector/receiver for remotes. I guess you only need 1.st component in the chain.
Second half, shor characteristics from 2 different phototransistors.
As you can see - one for visible light and IR, the other for IR only.
I'm sure there are several out there, all sensitive within a spesific range of freq.
