Efficient and Stable Perovskite Solar Cells with a High Open‐Circuit Voltage Over 1.2 V Achieved by a Dual‐Side Passivation Layer
Ju‐Hyeon Kim, Yong Ryun Kim, Juae Kim, Chang‐Mok Oh, In‐Wook Hwang, Jehan Kim, Stefan Zeiske, Taeyoon Ki, Sooncheol Kwon, Heejoo Kim, Ardalan Armin, Hongsuk Suh, Kwanghee Lee
IF 26.8
Advanced Materials
Adv. Mater. 2022, 34, 2205268 DOI: 10.1002/adma.202205268 There is an error in the grant number in the acknowledged funding information for the program of Future Hydrogen Original Technology Development in the originally published article. The grant number is corrected as “2021M3I3A1084747”, so the funding acknowledgement is revised as: “…by the program of Future Hydrogen Original Technology Development (No. 2021M313A1084747) through the NRF funded by MSIT…”
Photostable organic solar cells based on non-fullerene acceptors with an aminated bathocuproine electron transport layer
Yong Ryun Kim, Sanseong Lee, Juae Kim, Juhui Oh, Ju‐Hyeon Kim, Taeyoon Ki, Chang‐Mok Oh, In‐Wook Hwang, Hongsuk Suh, Kwanghee Lee, Heejoo Kim
IF 9.5
Journal of Materials Chemistry A
Solution-processed bathocuproine (BCP) has been widely used in fullerene (FA)-based organic solar cells (OSCs) for decades as an electron transport layer (ETL).
Efficient and Stable Perovskite Solar Cells with a High Open‐Circuit Voltage Over 1.2 V Achieved by a Dual‐Side Passivation Layer
Ju‐Hyeon Kim, Yong Ryun Kim, Juae Kim, Chang‐Mok Oh, In‐Wook Hwang, Jehan Kim, Stefan Zeiske, Taeyoon Ki, Sooncheol Kwon, Heejoo Kim, Ardalan Armin, Hongsuk Suh, Kwanghee Lee
IF 26.8
Advanced Materials
Suppressing nonradiative recombination at the interface between the organometal halide perovskite (PVK) and the charge-transport layer (CTL) is crucial for improving the efficiency and stability of PVK-based solar cells (PSCs). Here, a new bathocuproine (BCP)-based nonconjugated polyelectrolyte (poly-BCP) is synthesized and this is introduced as a "dual-side passivation layer" between the tin oxide (SnO<sub>2</sub> ) CTL and the PVK absorber. Poly-BCP significantly suppresses both bulk and interfacial nonradiative recombination by passivating oxygen-vacancy defects from the SnO<sub>2</sub> side and simultaneously scavenges ionic defects from the other (PVK) side. Therefore, PSCs with poly-BCP exhibits a high power conversion efficiency (PCE) of 24.4% and a high open-circuit voltage of 1.21 V with a reduced voltage loss (PVK bandgap of 1.56 eV). The non-encapsulated PSCs also show excellent long-term stability by retaining 93% of the initial PCE after 700 h under continuous 1-sun irradiation in nitrogen atmosphere conditions.
Antioxidant Effect of Ethyl acetate Fraction of Cyperus sanguinolentus Vahl in Caenorhabditis elegans
Jaeho Choi, Sang-Yeon Park, Juae Kim, Hojin Lee, Jun Hyeong Kim, In-Hyun Hwang, Daekeun Kim
Korean Journal of Pharmacognosy
In the process of finding antioxidants from native plants in Korea, the ethyl acetate fraction of Cyperus sanguinolentus Vahl (Cyperaceae) methanol extract was observed to have a strong scavenging effect on DPPH radicals. Superoxide dismutase (SOD), catalase, and oxidative stress resistance were measured using model system in combination with reactive oxygen species (ROS) levels in the ethyl acetate fraction of Cyperus sanguinolentus (EACS). In addition, to determine whether EACS-treated C. elegans produced resistance proteins to oxidative stress, we checked SOD-3 expression using transformant strain CF1553. As a result, the EACS increased SOD and catalase activity and reduced ROS accumulation in a dose-dependent manner. And, the CF1553 nematodes treated with EACS showed higher SOD-3::GFP intensity than the control group.
When Language Shapes Thought: Cross-Lingual Transfer of Factual Knowledge in Question Answering
Eojin Kang, Juae Kim
Multilingual large language models (LLMs) offer promising opportunities for cross-lingual information access, yet their use of factual knowledge remains highly sensitive to the input language. Prior work has addressed this through English prompting and evaluation, assuming that English-based reasoning is universally beneficial. In this work, we challenge that assumption by exploring factual knowledge transfer from non-English to English through the lens of Language and Thought Theory. We introduce Language-to-Thought (L2T) prompting, which aligns the model's internal ''thinking'' language with the source of knowledge. Across three languages and four models, L2T consistently outperforms English-based reasoning, reversing the expected advantage of English prompts. Our code is available at https://github.com/GeomeunByeol/Language2Thought.
Exploring Working Memory Capacity in LLMs: From Stressors to Human-Inspired Strategies
Association for Computational Linguistics 2025, Sumin Cho, Eunjin Hong, Juae Kim
Underline Science Inc.
Large language models (LLMs) exhibit inherent limitations in working memory, which often affect their overall capabilities. However, prior studies have largely focused on describing such constraints without identifying their causes or providing practical strategies to cope with them. In this paper, we investigate the limited working memory capacity of LLMs through a series of empirical studies. Specifically, we examine the factors involved in the limited capacity and explore strategies to make more effective use of it. Our analysis shows that the number and difficulty of tasks in a single input largely strain the working memory of LLMs. In response, we design a cognitive marker consisting of simple token sequences theoretically grounded in cognitive science. Further analyses show that the cognitive marker reduces the overall prediction difficulty and uncertainty for the models to process the input, and its effectiveness is confirmed across various evaluation settings. Overall, our study incorporates cognitively motivated perspectives into the analysis of model behavior and highlights the need for deeper exploration of working memory in LLMs.
Exploring the Impact of Occupational Personas on Domain-Specific QA
Eun-Young Kang, Jung-Lok Yu, Juae Kim
ArXiv.org
Recent studies on personas have improved the way Large Language Models (LLMs) interact with users. However, the effect of personas on domain-specific question-answering (QA) tasks remains a subject of debate. This study analyzes whether personas enhance specialized QA performance by introducing two types of persona: Profession-Based Personas (PBPs) (e.g., scientist), which directly relate to domain expertise, and Occupational Personality-Based Personas (OPBPs) (e.g., scientific person), which reflect cognitive tendencies rather than explicit expertise. Through empirical evaluations across multiple scientific domains, we demonstrate that while PBPs can slightly improve accuracy, OPBPs often degrade performance, even when semantically related to the task. Our findings suggest that persona relevance alone does not guarantee effective knowledge utilization and that they may impose cognitive constraints that hinder optimal knowledge application. Future research can explore how nuanced distinctions in persona representations guide LLMs, potentially contributing to reasoning and knowledge retrieval that more closely mirror human social conceptualization.
Exploring Working Memory Capacity in LLMs: From Stressors to Human-Inspired Strategies
Eunjin Hong, Sumin Cho, Juae Kim
Eunjin Hong, Sumin Cho, Juae Kim. Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics. 2025.
A Readability-Driven Curriculum Learning Method for Data-Efficient Small Language Model Pretraining
Suyun Kim, J.S. Park, Juae Kim
IF 2.2
Mathematics
Large language models demand substantial computational and data resources, motivating approaches that improve the training efficiency of small language models. While curriculum learning methods based on linguistic difficulty measures have been explored as a potential solution, prior approaches that rely on complex linguistic indices are often computationally expensive, difficult to interpret, or fail to yield consistent improvements. Moreover, existing methods rarely incorporate the cognitive and linguistic efficiency observed in human language acquisition. To address these gaps, we propose a readability-driven curriculum learning method based on the Flesch Reading Ease (FRE) score, which provides a simple, interpretable, and cognitively motivated measure of text difficulty. Across two dataset configurations and multiple curriculum granularities, our method yields consistent improvements over baseline models without curriculum learning, achieving substantial gains on BLiMP and MNLI. Reading behavior evaluations also reveal human-like sensitivity to textual difficulty. These findings demonstrate that a lightweight, interpretable curriculum design can enhance small language models under strict data constraints, offering a practical path toward more efficient training.
Towards Human-Interactive Controllable Video Captioning with Efficient Modeling
Yoonseok Heo, Taehoon Kim, Seunghwan Kim, Jungyun Seo, Juae Kim
IF 2.2
Mathematics
Video captioning is a task of describing the visual scene of a given video in natural language. There have been several lines of research focused on developing large-scale models in a transfer learning paradigm, with major challenge being the tradeoff between scalability and performance in limited environments. To address this problem, we propose a simple yet effective encoder–decoder-based video captioning model integrating transformers and CLIP, both of which are widely adopted in the vision and language domains, together with appropriate temporal feature embedding modules. Taking this proposal a step further, we also address the challenge of human-interactive video captioning, where the captions are tailored to specific information desired by humans. To design a human-interactive environment, we assume that a human offers an object or action in the video as a short prompt; in turn, the system then provides a detailed explanation regarding the prompt. We embed human prompts within an LSTM-based prompt encoder and leverage soft prompting to tune the model effectively. We extensively evaluated our model on benchmark datasets, demonstrating comparable results, particularly on the MSR-VTT dataset, where we achieve state-of-the-art performance with 4% improvement. In addition, we also show potential for human-interactive video captioning through quantitative and qualitative analysis.
Efficient and Stable Perovskite Solar Cells with a High Open‐Circuit Voltage Over 1.2 V Achieved by a Dual‐Side Passivation Layer
Ju‐Hyeon Kim, Yong Ryun Kim, Juae Kim, Chang‐Mok Oh, In‐Wook Hwang, Jehan Kim, Stefan Zeiske, Taeyoon Ki, Sooncheol Kwon, Heejoo Kim, Ardalan Armin, Hongsuk Suh, Kwanghee Lee
IF 26.8
Advanced Materials
Adv. Mater. 2022, 34, 2205268 DOI: 10.1002/adma.202205268 There is an error in the grant number in the acknowledged funding information for the program of Future Hydrogen Original Technology Development in the originally published article. The grant number is corrected as “2021M3I3A1084747”, so the funding acknowledgement is revised as: “…by the program of Future Hydrogen Original Technology Development (No. 2021M313A1084747) through the NRF funded by MSIT…”
Photostable organic solar cells based on non-fullerene acceptors with an aminated bathocuproine electron transport layer
Yong Ryun Kim, Sanseong Lee, Juae Kim, Juhui Oh, Ju‐Hyeon Kim, Taeyoon Ki, Chang‐Mok Oh, In‐Wook Hwang, Hongsuk Suh, Kwanghee Lee, Heejoo Kim
IF 9.5
Journal of Materials Chemistry A
Solution-processed bathocuproine (BCP) has been widely used in fullerene (FA)-based organic solar cells (OSCs) for decades as an electron transport layer (ETL).
Efficient and Stable Perovskite Solar Cells with a High Open‐Circuit Voltage Over 1.2 V Achieved by a Dual‐Side Passivation Layer
Ju‐Hyeon Kim, Yong Ryun Kim, Juae Kim, Chang‐Mok Oh, In‐Wook Hwang, Jehan Kim, Stefan Zeiske, Taeyoon Ki, Sooncheol Kwon, Heejoo Kim, Ardalan Armin, Hongsuk Suh, Kwanghee Lee
IF 26.8
Advanced Materials
Suppressing nonradiative recombination at the interface between the organometal halide perovskite (PVK) and the charge-transport layer (CTL) is crucial for improving the efficiency and stability of PVK-based solar cells (PSCs). Here, a new bathocuproine (BCP)-based nonconjugated polyelectrolyte (poly-BCP) is synthesized and this is introduced as a "dual-side passivation layer" between the tin oxide (SnO<sub>2</sub> ) CTL and the PVK absorber. Poly-BCP significantly suppresses both bulk and interfacial nonradiative recombination by passivating oxygen-vacancy defects from the SnO<sub>2</sub> side and simultaneously scavenges ionic defects from the other (PVK) side. Therefore, PSCs with poly-BCP exhibits a high power conversion efficiency (PCE) of 24.4% and a high open-circuit voltage of 1.21 V with a reduced voltage loss (PVK bandgap of 1.56 eV). The non-encapsulated PSCs also show excellent long-term stability by retaining 93% of the initial PCE after 700 h under continuous 1-sun irradiation in nitrogen atmosphere conditions.
