Luminescent solar concentrators (LSCs) with high performances depend on not only the luminescent materials, but their dispersed polymer matrixes. However, carbon dots (CDs)-based LSCs suffer from aggregation-caused fluorescence quenching with the increased concentration of CDs in polymer matrix. To solve this issue, a novel solid-state photoluminescent (PL) silicone-carbon dots (Si-CDs) composites was synthesized by one-step solvothermal treatment of citric acid, dicyandiamide and 3-aminopropyltriethoxysilane (APTES). The solid-state PL Si-CDs showed yellow-green emission at 525 nm under excitation of UV light. For better dispersion of Si-CDs, two types of silicone dendrimers (denoted as D1 and D2) were designed and synthesized via a transesterification and hydrosilylation reaction method. The structure differences between D1 and D2 are the contents of phenyl and methoxy groups. Remarkably, silicone dendrimers with high loading of Si-CDs (up to 35 wt%) could be obtained owing to their good compatibility. Single-layered LSCs could be prepared easily by directly casting the above mixtures on glass substrates followed by room temperature curing. The external optical efficiency (ηopt) of 7.58%, 5.38% had been achieved from D1 and D2 based LSCs (25 × 25 × 1 mm), respectively. This work provides a convenient method for preparing highly efficient LSCs, posing great potential in various specific applications.