 we explore the limits of modifying metal work functions with large 
 molecular dipoles by systematically increasing the dipole moment of 
 archetype donor  acceptor molecules in self - assembled monolayers 
 on gold . 
 contrary to intuition , we find that enhancing the dipoles 
 leads to a reduction of the adsorption - induced change of the work 
 function . using atomistic simulations , we show that large dipoles 
 imply electronic localization and level shifts that drive the interface 
 into a thermodynamically unstable situation and trigger compensating 
 charge reorganizations working against the molecular dipoles . under 
 certain circumstances , 
 these are even found to overcompensate the 
 effect that increasing the dipoles has for the work function . 
Supplementary Material