Polydimethylsiloxane-Based Quantum Dot Color Conversion Layers for QD-OLED Applications

Quantum dot (QD)-based color conversion layers are key components in QD-OLED displays because they can provide high color purity and simplified pixel architectures by converting blue emission from OLEDs into red or green light. The performance of the color conversion layer strongly depends on the blue light absorption, blue leakage, and overall emission efficiency of the display. We fabricated the color conversion layers using a thermally curable polydimethylsiloxane (PDMS) matrix, and their color conversion characteristics were systematically compared with those of QD-only layers. In the QD-only layers, the intensity of the converted green emission increased with increasing QD concentration due to enhanced absorption of blue light emitted from the OLED. However, a large fraction of blue light was transmitted through the layer without being absorbed by the QDs, resulting in a significant blue leakage and a relatively low output/input efficiency below 10%. In contrast, PDMS-based QD color conversion layers exhibited substantially improved color conversion characteristics. By varying the QD concentration and controlling the layer thickness, blue leakage was significantly suppressed and the green emission intensity increased. The maximum color conversion efficiency of 30.0% was obtained at a QD concentration of 8.3 wt% with a layer thickness of 35.9 µm.