2.1. Definition and Research Progress of Innovation Chain
The IC is defined from a chain perspective for defining innovative behavior, indicating a chain-like process of input to output, from basic research to the production and commercialization of innovative results. Unlike concepts such as the innovation network or innovation ecosystem, the IC stems from an academic interest in the innovation process.
Freeman [
27] expanded on the Schumpeterian concept of innovation, dividing innovation into two processes: invention and diffusion. As the path of technological progress continued to evolve, the boundaries between knowledge innovation and technological innovation increasingly merged, further extending innovation into four stages: basic research, applied research, development, and post-research (also known as diffusion) [
28]. In the context of the global technological revolution achieving disruptive breakthroughs, the basic research stage, namely knowledge innovation, has become increasingly critical in innovation competition.
Early research on the IC primarily focused on exploring its content, including defining the IC from different perspectives such as knowledge innovation, technological innovation, and changes in the subjects of innovation. Researchers also investigated its characteristics [
29]. Regardless of the perspective taken, the core concepts include (1) several functional nodes of the IC, involving various types of actors in innovation activities such as enterprises, governments, financial institutions, research institutions, intermediaries, and more; (2) relationships between these functional nodes, manifesting as cooperation, strategic alliances, and other specific forms; (3) the sharing of information and knowledge among these nodes, including formal and informal channels and mechanisms; and (4) the external support system for the operation of the IC, encompassing institutions, macro-industrial policies, markets, changes in consumer demand, and other macro–micro factors. Another body of literature interpreted the models and structures of the IC from perspectives like enterprise value creation [
30], innovation boundaries [
31], and global value chains [
32]. These studies also analyzed and discussed various heterogeneous influencing factors on different dimensions to understand and analyze the key links, influencing factors, and interactions in the innovation process. The recent literature has focused on the inherent logic and interactive paths of the IC with the industrial chain [
33] and the value chain [
34].
As the scope and extension of the IC continue to expand, its importance has risen to the level of national strategy. In China’s 14th Five-Year Plan, enhancing the overall efficiency of the IC is identified as a crucial aspect of driving innovation-led development. Improving the connectivity between different stages and functional nodes of the IC and optimizing the integration between the IC and the industrial chain and value chain holds great significance for high-quality economic development driven by innovation. The key to achieving these goals lies in breakthroughs and development in general technology, disruptive technology, and cutting-edge technology.
2.2. The Theoretical Logic of Enterprise Digital Transformation Affecting Green Innovation
According to IC, the GIC can be divided into three stages: basic research, applied research, and the adoption of new technologies. Basic research involves knowledge innovation, with universities and research institutes as the main actors. This type of innovation may precede the green technology needs of enterprises and has the characteristics of a public good. Applied research involves converting knowledge into new technologies based on the green technology needs of enterprises. This is a critical link in the GIC, as it transforms knowledge into innovation that can be commercialized. The adoption of new technologies includes innovations in green business models and market innovations, which represent the stage where GI outcomes are transformed. From the value sources of GIC’s three stages, the value of basic research comes from the knowledge innovation of universities, scientific research institutions, and other subjects. The value of applied research comes from the green technology innovation demand of enterprises, which promotes the transformation of knowledge innovation into green technology innovation. The value created in the adoption stage from the application of new technology to meet the needs of consumers. But the total value of GIC is not a simple sum of the three stages. Under the interaction of different subjects in three stages, the total value of GIC is formed by nonlinear summation.
Enterprises are important functional nodes in the GIC. The impact of DT on GI can be seen in two main aspects. Firstly, it is reflected in the optimization of the internal functional nodes of the GIC. Secondly, it is manifested in the facilitation of the connections between different functional nodes, therefore enhancing the overall efficiency of the GIC and increasing its total value (
Figure 1).
Regarding the different stages of the GIC, DT can be seen as an effort to apply digital technology to the goals of applied research. It can also be seen as the enterprises’ efforts in the adoption of digital technology. By undergoing DT, enterprises gain access to digital technologies with the characteristics of generality, openness, and availability. These technologies serve as the foundation for the fusion of digital and green technologies and the incubation of new technologies. For example, digital twin technology provides a virtual space for testing the feasibility of new technologies, reducing the risk and cost of research and development. Additionally, big data analytics enhances the ability to analyze vast and diverse structured or unstructured data sources, facilitating the discovery of potential issues in existing GI systems and optimizing the GI process. Some artificial intelligence technologies can replace human labor in high-risk, high-precision experiments, expanding the scenarios of digital technology application in green products. Digital technology also enables enterprises to connect with consumers and innovate in green business models. Companies can better understand consumer demands for green products and services, optimize innovation strategies, and adjust innovation resource allocation after DT. Digital technology has the potential to transform the direction of technology demand, leading to a shift from pollution-oriented to green-oriented innovation. Given these considerations, the hypotheses are put forward.
Hypothesis 1 (H1): Enterprise DT has a positive effect on GI.
While digital technology possesses generality, it also comes with complexity and skill biases. The success of the fusion of digital and green technologies, as well as the conversion of digital technology into secondary innovation, relies heavily on the human capital within enterprises. On one hand, enterprises need employees with knowledge and skills related to digital technology to facilitate its diffusion and application. This drives some enterprises to actively recruit employees who are proficient in digital technology during the DT process to optimize their human capital structure for GI. On the other hand, one of the channels for the formation of human capital is through employee learning and interaction, promoting the diffusion of heterogeneous knowledge. Digital management tools, by optimizing information flows and standardizing communication processes, reduce internal control and communication costs and encourage active learning and idea exchange among employees, contributing to the formation of new ideas and knowledge for GI.
Moreover, the application of digital technology will change the way companies train their employees, providing various forms of training such as remote training, self-directed learning, and personalized training. This diversification of training methods enhances the development of human capital through multiple channels. Employee training not only promotes the cultivation of human capital within the enterprise but also provides positive feedback for digital technology adoption, creating a positive loop for DT. The positive relationship between human capital and GI has been certificated in previous research [
35,
36].
Certainly, the realization of GI value by enterprises depends on the interaction of other resources such as funding, technology, and information. The new factor of data not only replaces traditional high-energy, low-output factors but also affects the direction of technological demand, subsequently influencing GI. Data-driven decision-making models facilitate quick responses to market demands and optimization of innovation strategies, improving the efficiency of GI supply and demand matching. DT improves GI by enhancing the optimization of human capital structure and improving the allocation of innovation resources. This is reflected in the GIC as an increase in the value of individual functional nodes. Therefore, the following two research hypotheses are proposed.
Hypothesis 2 (H2): Enterprise DT promotes GI through human capital cultivation.
Hypothesis 3 (H3): Enterprise DT promotes GI by improving the ability to allocate innovative resources.
Furthermore, we expand our analytical perspective to the interactive dimension of various functional nodes within the IC. In the context of conventional technological advancement pathways, a majority of enterprises’ GI activities are typically confined within the boundaries of the enterprise itself, and the realization of value from GI remains limited to the stages of applied research or the adoption of new technologies. The compartmentalization of innovation activities results in fragmentation within the GIC, particularly between the phases of basic research and subsequent stages, rendering innovation resources challenging to effectively allocate along the upstream and downstream of the IC, thereby impacting the overall value of GI. According to research conducted in the published literature [
37], innovation activities concentrated solely on individual functional nodes within the IC, i.e., independent organizational innovation, especially within enterprises with weak innovation capabilities, constitute a major contributing factor to the decline in the quality of green technological innovation. Moreover, compared to general innovation, GI is characterized by a higher level of asset specificity and uncertainty. Cooperative innovation represents a significant form of resource allocation within the IC. In practice, cooperative innovation with supply chain partners, competitors, and even academic and research institutions has become a crucial strategic approach for many enterprises to reduce uncertainty and enhance the value of GI [
38,
39].
Although DT is mainly an initiative taken by enterprises, it can promote cooperative innovation and improve the efficiency of GIC. On the one hand, DT enhances the efficiency of interacting with other stakeholders in the GI process. On the other hand, digital technology has significantly improved information asymmetry and reduced the transaction costs of innovation participants. When the frequency of cooperative innovation between enterprises, universities, and research institutions increases, it will not only bring more external resources to enterprises but also stimulate GI with more technological novelty, thus improving the quality of GI [
40]. Based on the above analysis, the following hypothesis is proposed:
Hypothesis 4 (H4): Enterprise DT promotes GI by enhancing cooperative innovation capabilities.
Figure 1 presents our research framework, which illustrates the relationship between DT and GI. This includes both the direct effects of DT on GI and the indirect effects through three channels: human capital cultivation, innovation resource allocation, and collaborative innovation. Additionally,
Figure 1 outlines the hypotheses of our study.