Accurate vapor pressure prediction for large organic molecules: application to materials utilized in OLEDs

Abstract: We present a theoretical method based on molecular dynamics (MD) simulations for prediction of saturated vapor pressure of liquids constituting of large organic molecules at various temperatures. The approach is based on free energy calculations at fixed temperature and subsequent Gibbs-Duhem integration over the interval of temperatures. MD simulations were carried out with two parameterizations of the force field: commonly used one and developed specifically for the investigated molecules. Results of theoretical approach are compared with experimental measurements for a set of 6 molecules utilized in organic light emitting diodes (OLED). We suggest that the developed methodology would be useful in various areas of molecular design which require prediction of vapor pressures for liquids of large and chemically diverse compounds.