Solvent-free, direct printing of organic semiconductors in atmosphere

摘要

Additive, solvent-free printing of molecular organic semiconductors in ambient atmosphere is demonstrated, by evaporating organic source material into nitrogen carrier gas, collimating and impinging it onto a substrate where the organic molecules condense. A surrounding annular guard flow focuses the primary jet and shields it from contact with the ambient oxygen and moisture, enabling device-quality deposits. As an example, electroluminescence efficiency of organic light emitting devices (OLEDS) with emissive layers printed in air is shown to increase with guard flow rate, attaining parity with all-vacuum thermally evaporated OLEDs.