devices, sensing, biological imaging, and display [1][2][3][4] due to their long-life characteristics. Carbon dots (CDs) as the emerging carbon nano-luminescent materials, due to their unique optical properties, low toxicity, chemical inertness, and easy preparation, [5][6][7][8] stand out among many luminescent materials and become the important parts of RTP materials. Different CDs fluoresce in unique ways under different states. CDs in dilute solutions have different photophysical properties compared with solid or highconcentration solutions. Moreover, CDs follow the aggregation-caused quenching (ACQ) effect. [9] For example, the luminescence of CDs will be weakened in the solid-state. The reasons for the quenching are the excessive fluorescence resonance energy transfer (FRET) and the π-π stacking interaction between the carbon cores, resulting in the non-radiative loss of the excited state. [10][11][12][13] The luminescence of CDs in the solid-state is obviously quenched due to the ACQ effect, which severely limits their development in the direction of RTP materials.Theoretically, the best way to prepare CDs-based RTP materials and solve the problem of CDs luminescence quenching in the solid-state, the current effective method is to stabilize triple states (T 1 ) , suppress the nonradiative transitions, and limit vibrations and rotations of molecules by embedding CDs into appropriate substrates with the help of hydrogen bonds. [14][15][16][17] The phosphorescence phenomenon in the CDsbased composite system has attracted more and more attention in recent years. [14][15][16][18][19][20][21] Gou et al. reported a series of RTP composites based on tunable polyaniline CDs (PACDs) and polymer matrices (polyacrylic acid, polyacrylamide (PAM), polyvinyl alcohol (PVA)). Only green RTP emissions with adjustable lifetime have been realized by the hydrogen bonding formed between polymer matrices and PACDs. [14] Li et al. prepared an efficient CDs-based RTP material by mixing N-doped CDs (NCDs) with urea and biuret through one-pot heating method. The appearance of CN bonds creates new energy level structures. The interaction of the mixture of biuret and NCDs with composite matrices is This is the first report of full-color afterglow composites composed of four multicolored (blue, green, orange, and red) carbon dots (CDs) in polyacrylamide (PAM) matrix. Thus, adjustable four-color room-temperature phosphorescence (RTP) CDs@PAM composites are prepared on a PAM platform. The abundant amide groups in PAM are connected to the functional groups in CDs by hydrogen bonds, which promote the intersystem crossover and inhibit the non-radiative relaxation of triple states (T 1 ) in CDs@PAM and effectively shield the quenching agents such as oxygen. Furthermore, the rigid hydrogen bond mesh structure is beneficial to the stability of T 1 in CDs@PAM. In addition, the results of electron spin resonance reveal that the afterglow of CDs@PAM composites is not caused by oxygen defects and the increase of oxygen defects hinders the emissio...