As a new type of luminescent material, carbon dots (CDs) have attracted increased attention for their superior optical properties in recent years. However, CDs generally suffer from aggregation-induced luminescence quenching, which means they are highly emissive in solution or a dispersed state but dramatically quenched in a solid or aggregated state. This problem significantly limits the application of CDs, partially in the solid-state light-emitting devices. In this work, a new kind of solid-state emissive CDs have been synthesized via simple one-step hydrothermal strategy. Under 450 nm excitation, the CDs exhibit bright green luminescence in the solid state, with a quantum yield of 26%. The luminescence lifetime of the CDs is only 4 ns. Employing the CDs as a color converter, white light-emitting diodes were fabricated and a visible light communication system with high performance (modulation bandwidth of 55 MHz, data transmission rate of 181 Mbps) was realized.