关键词: 溢出效应, 双寡头竞争, 绿色研发

Abstract: As consumers increasingly prefer green energy-efficient products, enterprises engage in green research and development (R&D) to improve the environmental performance of their products and strengthen  market competitiveness. However, because green R&D exhibits spillover effects, competitors can easily learn from or imitate these efforts, reducing their won R&D costs. Some competitors may even “leapfrog” and achieve an advantage in product greenness. This creates a dilemma for firms: should they engage in green R&D early to gain a first-mover advantage, or should they wait and benefit from competitors’ spillovers? To address problem, this paper develops a two-period duopoly game model. The results show that the there are two pure-strategy Nash equilibria in the timing of green R&D. When the spillover rate is low, the duopolies choose to conduct green R&D in the first period. However, the equilibrium profit in this scenario is lower than if they conduct R&D in the second period, creating a classic prisoner’s dilemma. When the spillover rate is high, the duopolies choose to conduct green R&D at different periods. In this case, the firm that invests first achieves higher profits and exerts greater R&D effort than the later firm. As the spillover rate increases, the first-mover’s profit and R&D effort gradually decline, while the second-mover’s profit and effort increase. Furthermore, in the scenario where the two firms conduct R&D in different periods, a mixed-strategy Nash equilibrium also exists. In this case, the probability that each firm conducts green R&D in the second period increases with the spillover rate.

Key words: spillover effects, duopoly competition, green research and development (R&D)