Tuning the work function of VO2(1 0 0) surface by Ag adsorption and incorporation: Insights from first-principles calculations.

VO 2 is an attractive material for application to thermochromic optoelectronic devices such as smart windows, and Ag/VO 2 double-layered structure can effectively decrease the phase transition temperature ( T c ) of VO 2 thin film, which is very important for practical application of VO 2 . Previous works has shown that the decrease in phase transition temperature ( T c ) seems to be relevant with the work function of VO 2 in Ag/VO 2 double-layered thin film, although the underlying mechanism of tuning its T c by Ag incorporation and adsorption on the VO 2 (1 0 0) surface has been rarely investigated. Our first-principles calculations reveal that the adsorption of Ag atoms on the VO 2 (1 0 0) surface rather than incorporation of Ag exhibits a lower work function, which is ascribed to an integrated effect of charge transfer from Ag to VO 2 (1 0 0) surface and enhanced surface dipole moment. The results suggest that the decrease in work function of VO 2 with Ag adsorption favors the reduction in T c . The current findings are helpful to understand the fundamental mechanism for yielding high-efficiency VO 2 -based optoelectronic devices. [ABSTRACT FROM AUTHOR]