Aerosol Jet Printed Polymer‐Free High Aspect Ratio Quantum Dot Films for Enhanced Color Conversion

Quantum dot (QD) color conversion layers (CCLs) are a promising route toward wide color gamut, simplified display architectures. However, simultaneously achieving high optical quality, fine patterning resolution, and scalable processing remains challenging. Here, we report a polymer‐free aerosol jet printing approach for fabricating high‐aspect‐ratio QD CCLs with precisely controlled morphology and optical performance. By tuning the aerosol focus ratio to induce in‐flight droplet drying, we achieve pinned contact‐line deposition that enables multilayer QD films with thicknesses up to approximately 10 µm while maintaining lateral feature widths of approximately 50 µm. These polymer‐free QD films exhibit strong blue‐light absorption and efficient wavelength down‐conversion, yielding blue light leakage below 0.25% and conversion efficiencies approaching 18% without the use of external color filters. The printed QD layers are integrated directly onto blue OLED unit devices and a 0.7‐inch OLED‐on‐silicon (OLEDoS) microdisplay, demonstrating high‐purity red emission with no degradation of device electrical performance. This work establishes aerosol jet printing as a powerful materials processing strategy for scalable, high‐resolution QD color conversion in next‐generation microdisplay and near‐eye display technologies.