Research on the Mechanism of Collaborative Innovation in Green Technology among Supply Chain Enterprises Based on Cost Sharing and Market Competition

Supply chain green technology collaborative innovation is an important means for enterprises to improve the greenness of their products. This paper takes supply chain green technology innovation collaboration as the research object and constructs a stochastic differential game model, which not only provides reference for enterprises to choose the optimal type of technology innovation by combining with their own characteristics, but also provides a reference for their innovation decision-making in different market competition environments. The study shows the following: (1) in green product innovation, the formation of the cost-sharing contract is less affected by the intensity of competition in the green market when the market preference for greenness is relatively low. Therefore, government subsidies become an important tool to effectively guide the market mechanism to achieve the desired goal. As market competition intensifies, manufacturers’ incentives to suppliers will shift from reducing costs to increasing demand. (2) In green process innovation, when the intensity of green competition is low and suppliers’ process innovation efficiency is high, manufacturers should bear more costs; when the market preference for greenness is low, the market competition is intense, and the suppliers’ process innovation efficiency is low, the suppliers should bear more costs to help the manufacturers gain more market shares. (3) When retailers’ preference for greenness is relatively low, the government subsidy becomes an important tool to effectively guide the market mechanism to achieve the desired goal. (4) When the retailer’s green promotion performance is higher than the manufacturer’s, the manufacturer should bear more green promotion costs; conversely, the retailer should bear more green promotion costs. (5) Over time, the marginal increase in price over the marginal increase in greenness helps stabilise price volatility, considering consumer preferences. Conversely, it helps to increase the average value of prices.