Browsing by Author "Lee, Sangsu"

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Semi-transparent metal electrode-free all-inorganic perovskite solar cells using floating-catalyst-synthesized carbon nanotubes
(2024-03) Yoon, Saemon; Lee, Il Hyun; Han, Jiye; Bahadur, Jitendra; Lee, Seojun; Lee, Sangsu; Kim, Dong Suk; Mikladal, B.; Kauppinen, Esko I.; Kang, Dong Won; Jeon, Il
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Perovskite solar cells offer a promising future for next-generation photovoltaics owing to numerous advantages such as high efficiency and ease of processing. However, two significant challenges, air stability, and manufacturing costs, hamper their commercialization. This study proposes a solution to these issues by introducing a floating catalyst-based carbon nanotube (CNT) electrode into all-inorganic perovskite solar cells for the first time. The use of CNT eliminates the need for metal electrodes, which are primarily responsible for high fabrication costs and device instability. The nanohybrid film formed by combining hydrophobic CNT with polymeric hole-transporting materials acted as an efficient charge collector and provided moisture protection. Remarkably, the metal-electrode-free CNT-based all-inorganic perovskite solar cells demonstrated outstanding stability, maintaining their efficiency for over 4000 h without encapsulation in air. These cells achieved a retention efficiency of 13.8%, which is notable for all-inorganic perovskites, and they also exhibit high transparency in both the visible and infrared regions. The obtained efficiency was the highest for semi-transparent all-inorganic perovskite solar cells. Building on this, a four-terminal tandem device using a low-band perovskite solar cell achieved a power conversion efficiency of 21.1%. These CNT electrodes set new benchmarks for the potential of perovskite solar cells with groundbreaking device stability and tandem applicability, demonstrating a step toward industrial applications. (Figure presented.).
Understanding the Initial Journey of UX Designers Toward Sustainable Interaction Design : A Focus on Digital Infrastructure Energy Reduction
(2024-07-01) Lee, Minha; Jun, Jian; Lee, Sunok; Lee, Sangsu
A4 Artikkeli konferenssijulkaisussa
Environmental sustainability is increasingly important, and actions on “digital sustainability” are expanding to reduce energy consumption from digital infrastructures. As many digital services today have extensive user bases, exploring sustainable design features holds signifcant potential for reducing environmental impact. However, further exploration of foundational research is still necessary to enable broader and more efective adoption of digital sustainability in design practice. This study focuses on understanding important considerations when encouraging more designers, especially those with limited expertise in sustainability-oriented design, to integrate sustainable practices into digital services—acknowledging that embracing unfamiliar approaches presents natural challenges. We conducted design workshops and debriefng interviews with user experience (UX) designers unfamiliar with design for sustainability to explore their early encounters with sustainable interaction design (SID) in the context of digital infrastructure energy reduction. Our study provides insight into designers’ initial perceptions and challenges with sustainable design and discusses opportunities for their broader engagement.
Unlock Life with a Chat(GPT) : Integrating Conversational AI with Large Language Models into Everyday Lives of Autistic Individuals
(2024-05-11) Choi, Dasom; Lee, Sunok; Kim, Sung In; Lee, Kyungah; Yoo, Hee Jeong; Lee, Sangsu; Hong, Hwajung
A4 Artikkeli konferenssijulkaisussa
Autistic individuals often draw on insights from their supportive networks to develop self-help life strategies ranging from everyday chores to social activities. However, human resources may not always be immediately available. Recently emerging conversational agents (CAs) that leverage large language models (LLMs) have the potential to serve as powerful information-seeking tools, facilitating autistic individuals to tackle daily concerns independently. This study explored the opportunities and challenges of LLM-driven CAs in empowering autistic individuals through focus group interviews and workshops (N=14). We found that autistic individuals expected LLM-driven CAs to offer a non-judgmental space, encouraging them to approach day-to-day issues proactively. However, they raised issues regarding critically digesting the CA responses and disclosing their autistic characteristics. Based on these findings, we propose approaches that place autistic individuals at the center of shaping the meaning and role of LLM-driven CAs in their lives, while preserving their unique needs and characteristics.