VIsible Light Photodiode
Sorry photo detectors do not work that way.

Like an ohm meter it generates a constant current except proportion to light. This means it will gen less voltage drop across the diodeand more thru the series circuit resistor (300R?) The cathode is reverse biased to V+ to reduce leakage. 3v? 

photo diodes , PD are rated in [Amps per Watt] of light. Scaled to this small area , it is same as [mA/mW] 0.6 is an excellent value for a 5mm PD.
Assuming you are correct that it is IR, use this,  http://www.digikey.com/product-detail/en/SFH229FA/475-1079-ND/607288