Yes you can actually. The same developer that created the sixaxis app on the playstore created a pair tool for windows. Go here
Dancing Pixel Studios and download the tool. Connect your ps3 pad to your computer using the same usb cable that came with your ps3 to charge. Then open the sixaxis app on your nexus and click start it will show you your bluetooth address though it wont find the controller. Now open the pair tool on your computer and change the bluetooth address to the one on your nexus. click save and close. You should be paired to your nexus now. Thats what i did. Now whenever you want to use your ps3 pad on your ps3 all you have to do is reconnect it to your ps3 like if you were charging it and it will again be paired to your ps3.