The 741 is ancient and won't work with a total 5v supply , and it's input isn't compliant down to the 0v supply.
Try 1/2 a LM358 - that'd be OK. And set your arduino a/d reference to 1.1v for better resolution.
But in general a photodode detector is much better run as a current source with a transconductance amplifier - I'll see if I can dig out a reference.....
Allan