| Nov 21, 2025 |
Carbon nanodot ink enables persistent invisible printing at high resolutionA water soluble carbon nanodot ink produces bright long lasting invisible prints with micrometer scale detail and high accuracy for secure and low cost applications.(Nanowerk News) A recent study in Acta Physico-Chimica Sinica ("Phosphorescent carbon nanodot inks for scalable and high-resolution invisible printing") shows that a new water soluble phosphorescent carbon nanodot ink can produce sharp invisible prints that remain visible after the light source is removed. |
| Fluorescent inks fade quickly because they rely on short lived singlet excitons. The new ink uses long lived triplet excitons, which continue to emit light after excitation stops. This makes it suitable for applications that need information to remain readable over time, including multi level security markings and high contrast sensing. |
| Carbon nanodots are attracting interest for their bright emission and small size. Here they form the basis of an ink that becomes phosphorescent through spatial confinement during printing. That confinement stabilizes the triplet excitons and produces bright, long lasting light emission. |
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| Ultra-high resolution and high fidelity scalable, invisible printing of phosphorescent carbon nanodots ink without a substrate. (Image: Frontiers Journals) |
| The authors report that the ink can reproduce complex text and patterns at micrometer scale resolution. It achieved 2480 by 3508 dpi, which corresponds to a feature size of about 100 micrometers. It accurately printed text as small as 5 point with line widths as fine as 0.05 point. It also maintained more than 98.7 percent accuracy when rendering an image containing 870000 pixels across five types of paper. |
| The researchers used the same method to produce a 200 page blank book that displays phosphorescent writing. They describe the approach as a route toward scalable, low cost and high resolution phosphorescent printing platforms. |
| Source: Frontiers Journals (Note: Content may be edited for style and length) |
