An evaporator for vaporizing organic material is described. The evaporator includes a first chamber having a nozzle adapted to be directed to a substrate to be coated; at least one second chamber for vaporizing the organic material; at least one vapour channel for guiding vaporized organic material from the at least one second chamber to the first chamber; wherein the first chamber is adapted to provide vaporized organic material to the nozzle corresponding to a first virtual sublimation surface, and the at least one second chamber being adapted to provide during operation a second sublimation surface area, wherein the second sublimation surface area corresponds to at least 70 percent of the first virtual sublimation surface.
