Building a quantum network is the ultimate goal of quantum information science. Among the candidates to realize quantum node, quantum repeater, and quantum channel, the solid-state emitters are particularly outstanding because of the presence of the spin-photon interface. Some of the solid-state emitters such as carbon nanotubes, color centers, transition metal ions, and rare earth ions can give telecom wavelength emission at room temperature. These emitters have different origins of single-photon emission. Here, the basic properties of each kind of emitter and their progress towards applications are reviewed. This review also introduces the current efforts to improve the emitters' brightness by integrating them into nanostructures.