Non-inverting op amp on breadboard isn't working
A uA741 will only be able to get within about 1V of the minus supply typically, and within 5V minimum 2V typical of the + supply with a 2K load. The 741 is not a single-supply op-amp. 

Increase R2 and R3 to more like 10K each and it should 'typically' give you 10V out with a 12V supply. It's not guaranteed though and is not good design. Better to use a more appropriate op-amp within its datasheet guaranteed limits.  

A better choice would be 1/2 an LM358 which is an ultra-cheap single supply dual op-amp. 

By the way, this is not a "voltage doubler" which by convention applies to a power supply. It is an amplifier with a gain of +2. The power is intended to come from the 12V supply.