This expression highlights that the work function ϕ also depends on the the dipole moment µ 0 and polarizability α of the molecules, besides the surface coverage θ and the lattice constant of the absorbate d. Notice that an effective polarizability α ′ is used to represent the properties of the absorbed molecules in Eq. 5, which is usually an order of magnitude larger than free molecular polarizability . Despite being acknowledged to fluctuate with the coverage rate, this equation can serve as a useful initial reference to screen potential molecules for photosensitizers according to the intended work function . Indeed, this relationship between both properties makes it important to regulate the polarizability of molecules for achieving a desired electrochemical behavior. Through this connection, it can be seen that molecules with higher polarizability tend to facilitate electron injection while those with lower polarizability tend to facilitate hole injection .