I'm not sure that you do need an op-amp.
You would use an op-amp to increase the sensitivity of the circuit when the IR sensor is illuminated.
Your issue is when the sensor is obscured.
I would definitely be interested in increasing the sensitivity of the IR receiver, if possible.
You could do that by increasing the value of the 10kΩ resistor.
The same photo-current through a larger resistor develops a higher voltage.
I'd try that before thinking about using the op-amp.
1 Like