Reminder that QDs are really, really fast
August 15, 2025
Rasmus Larsen, writing for flatpanelshd:
“…the first 500Hz OLED monitor is now available, outpacing both 480Hz WOLED and, on paper, even faster LCD monitors…You do not need to render all your PC games at 500fps, but you can if you own the first 500Hz QD-OLED monitor.”
It’s exciting to see the first 500 Hz QD-OLED monitors hit the market—and a great reminder that quantum dots (QDs) are a big part of the super-speed story.
OLEDs are inherently fast. The electroluminescent layer in most OLED emitters can respond in as little as ~10 µs. In practice, measured gray-to-gray (GtG) transitions can be slightly slower because of the pixel driving electronics, capacitance, and image processing. Even so, commercial OLED TVs and monitors routinely complete full pixel transitions in well under 1 ms, enabling near–blur-free performance.
Samsung G60SF, the first 500Hz QD-OLED.
The Samsung G60SF referenced in Rasmus’ article claims a 0.03 ms (30 µs) response time. That’s a serious motion-clarity advantage, even if your GPU can’t push a full 500 fps. And in QD-OLED, that speed depends not just on the OLED itself but also on the color-conversion layer, aka the “QD” in “QD-OLED.”
In QD-OLED, red and green subpixels are formed by a thin layer of quantum dots printed over a blue OLED emitter. The QDs themselves are extremely fast, with typical photoluminescence lifetimes in the tens of nanoseconds, so they add virtually no delay. The system runs at the limit set by the OLED and its driving electronics.
QD-Converted OLED Response Time Simulator
Simple model where total pixel response time = Electronics + Blue OLED Emitter + Color Conversion. Adjust assumptions and compare converters. The y-axis is fixed and logarithmic so you can see how the total bar shrinks when using ultrafast QDs.
Max frame rate is calculated for ~99% settle within one frame (≈4.6τ), meaning the pixel reaches 99% of its final value before the next frame is drawn.
By contrast, if you swapped those QDs for conventional wide-color-gamut phosphors, the speed story changes. Green β-SiAlON phosphor has a microsecond-scale decay (~0.6–1.2 µs), so it’s still fast but not quite as instantaneous as QDs. Red KSF/PFS phosphor, however, has a millisecond-scale decay (~5–10 ms). In a high-refresh, low-persistence system, that red channel’s afterglow would dominate certain transitions—slowing effective response by orders of magnitude and creating visible motion trails.
You can explore this for yourself with the interactive QD-Converted OLED Response Time Simulator above, which shows how each component of the pixel, including electronics, OLED emitter, and color conversion, adds to the total response time and limits the maximum frame rate.
QDs help OLED keep its speed edge, especially in the red channel, where conventional phosphors can’t come close to matching nanosecond-class performance.
