## 2 Theoretical Foundations  
This study establishes a novel theoretical framework based on perceived value theory and the technology acceptance model (TAM), focusing specifically on university students' intentions to use LLMs for sustainable online consumption.  
Initially, [PERSON] [25] defined perceived value theory as the consumer's overall assessment of a product's utility based on a trade-off between gains and losses. The theory is composed of three core dimensions: perceived quality, perceived price, and perceived value. According to the theory, university users' usage decisions are based on a systematic weighing of benefits and costs [26]. Grounded in the affordances of LLMs and the context of sustainable e-commerce, the perceived value is defined as a user's personal appraisal of how effectively LLMs support their own sustainable purchasing behavior. In other words, it measures the extent to which users believe that interacting with LLMs helps them achieve their green consumption goals [22]. Because initial theories are commonly used to evaluate traditional consumer domains, this study constructs a new theoretical framework of perceived technology value. This framework includes performance expectancy value, information quality value, trust transfer value, green perceived value, and green self-identity value. This methodological choice is consistent with the characteristics of the research object.  
The current study employs the TAM proposed by [PERSON] [21] as the theoretical foundation, which has been proven to have stronger explanatory power in predicting the continue using intention of technology compared to other theoretical models [27]. The core concepts of the model include perceived usefulness (PU) and perceived ease of use (PEU). In particular, the TAM has been found to effectively explain users' attitudes and behavioral intentions toward LLMs [28; 29]. Especially when university students are the research subjects, TAM is particularly effective in explaining the use behavior of LLMs [30]. Based on the above-mentioned theoretical basis, this study uses the two core variables of TAM (PU and PEU) as mediating variables. The aim is to systematically examine how university student users' perceptions of the value of LLMs influence the continued intention to use LLMs through perceived usefulness and perceived ease of use when the LLMs act as green communicators.  
In summary, the present study adopts an integrated framework combining the theory of perceived value and the theory of planned behavior. This phenomenon can be attributed to the dual role university students play as both technology users and consumers in the context of LLMs being applied to online eco-friendly product purchasing decisions. The theoretical underpinnings of perceived value theory and the technology acceptance model (TAM) complement each other in terms of model structure, thereby facilitating a more comprehensive understanding of the behavioral mechanisms underlying university students' adoption of large language models (LLMs) to assist in eco-friendly shopping. This enhanced understanding emerges from a more holistic consumer decision making perspective as opposed to a technologically focused viewpoint. By combining theories, this study constructs a theoretical model using a conceptual model [31]. It is a theoretical model that breaks through the limitations of traditional technology adoption research (Figure 1). This provides a more comprehensive theoretical perspective for understanding user usage and adoption motivations of LLMs in sustainable electronic consumption.