Hydrogen Peroxide‐Treated Carbon Dot Phosphor with a Bathochromic‐Shifted, Aggregation‐Enhanced Emission for Light‐Emitting Devices and Visible Light Communication

Abstract It is demonstrated that treatment of blue‐emissive carbon dots (CDs) with aqueous hydrogen peroxide (H 2 O 2 ) results in the green emissive solid state CD phosphor with photoluminescence quantum yield of 25% and short luminescence lifetime of 6 ns. The bathochromic‐shifted, enhanced green emission of H 2 O 2 ‐treated CDs in the powder is ascribed to surface state changes occurring in the aggregated material. Using the green emissive H 2 O 2 ‐treated CD phosphor, down‐conversion white‐light‐emitting devices with cool, pure, and warm white light are fabricated. Moreover, using the green emissive CD phosphor as a color converter, a laser‐based white‐light source is realized, and visible light communication with a high modulation bandwidth of up to 285 MHz and data transmission rate of ≈435 Mbps is demonstrated.