Fluid dynamics and mass transport in organic vapor jet printing

Abstract

Organic vapor jet printing (OVJP) is a high-resolution mask and solvent-free organic thin film deposition and patterning technique. In this work, we analyze factors that affect the material deposition rate and the dynamics of gas flow through an OVJP print head consisting of an array of micron-sized nozzles. Scaling laws governing carrier gas flow dynamics through a system of microchannels and nozzles are developed. From these laws, we predict the deposition rate and doping ratio of organic material as a function of carrier gas flow. The analysis is applied to an experimental print head, and is compared to results obtained via a more complex, direct simulation Monte Carlo model. The print head is used to grow efficient green phosphorescent organic light emitting diodes having an external quantum efficiency and luminance comparable to analogous devices grown by vacuum thermal evaporation. © 2012 American Institute of Physics.