This paper focuses on investigating the generation and manipulation of surface plasmon polaritons (SPPs) at the interfaces between quantum dot (QD) molecules and nanocomposite media. We utilize three different gate voltage values and incident laser field strengths to control the propagation of SPPs. We find a significant improvement in the SPPs' propagation length at the interfaces between the QD molecules and nanocomposite media. Additionally, under the Kerr effect, the gate voltage variation provides opportunities to control the SPPs' propagation. Through modifying the intensity and frequency of the incident probe field, we can manipulate various properties of SPPs at the suggested model's interfaces. Our results indicate a large enhancement in the SPPs' propagation length at the interfaces. Notably, we estimate the skin depth and wavelength of SPPs for three distinct values of the incident probe field and gate voltage applied in the QD molecules.