https://scholar.dgist.ac.kr/handle/20.500.11750/10027 2026-04-04T12:48:32Z https://scholar.dgist.ac.kr/handle/20.500.11750/59992 Title: Dopant-Chelating Polymeric Hole Transporting Material for Efficient and Humidity-Stable Quantum Dot Photovoltaics Author(s): You, Hyung Ryul; Lee, Duck Hoon; Kim, Suhwan; Park, Jin Young; Lee, Eon Ji; Kim, Hae Jeong; Ma, Hyeon Soo; Ka, Sungmin; Yong, Taeyeong; Lee, Yu Min; Kim, Younghoon; Moon, Byung-joon; Lee, Junwoo; Choi, Jongmin Abstract: Although conjugated polymers (CPs) have been extensively investigated as hole transport layers (HTLs) for optoelectronic devices, including colloidal quantum dot (CQD) photovoltaics, their stability is often limited by dopant-induced diffusion into the underlying photoactive regions. To overcome this, an ionic-electronic CP, PBTBDF-TEG, comprising benzodifuran and tetraethylene glycol (TEG)-substituted furan units is designed. PBTBDF-TEG effectively confines lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) dopants via lithium chelation by the TEG side chains, thereby suppressing dopant migration. This coordination also reduces the (010) π–π stacking distance, promoting hole transport by alleviating steric hindrance. Consequently, CQD solar cells incorporating LiTFSI-doped PBTBDF-TEG exhibited a power conversion efficiency (PCE) of 13.7%, exceeding the 11.8% achieved with the undoped counterpart. Furthermore, lithium chelation immobilizes water molecules, mitigating moisture ingress. As a result, the doped device retained over 90% of its initial PCE after 24 h under high humidity (85%–95% RH), whereas the undoped device exhibited substantial degradation. https://scholar.dgist.ac.kr/handle/20.500.11750/59901 Title: Enhancing Quantum Dot Photovoltaic Efficiency Through Defect Passivation and Triplet Energy Transfer with 9-Anthracenecarboxylic Acid Author(s): Lee, Eon Ji; Ham, Gayoung; Yun, Sunhee; You, Hyung Ryul; Yong, Taeyeong; Seo, Gayoung; Lee, Wonjong; Ma, Hyeon Soo; Park, Jin Young; Kim, Hae Jeong; Kim, Soo-Kwan; Kim, Younghoon; Lim, Jongchul; Kim, Minjun; Cha, Hyojung; Choi, Jongmin Abstract: A dual-functional electron transport layer (ETL) is reported for PbS colloidal quantum dot (CQD) photovoltaics by incorporating 9-anthracenecarboxylic acid (ACA) into a zinc oxide (ZnO) matrix. Despite its favorable electron transport characteristics and appropriate band alignment, intrinsic defects in ZnO, such as oxygen vacancies, remain a limiting factor in device performance. The carboxylate functional group of ACA effectively passivates these defects, thereby reducing trap-assisted recombination. Moreover, ACA, an acene-based π-conjugated molecule, efficiently generates triplet excitons. These triplets undergo triplet energy transfer to the PbS CQD layer, enhancing photocurrent generation. Owing to these synergistic effects, CQD photovoltaics (PVs) incorporating ACA-treated ZnO ETLs exhibit enhanced open-circuit voltage and short-circuit current density, resulting in a higher power conversion efficiency of 11.55% compared to 10.48% for control devices. This strategy highlights the combined advantages of electronic defect passivation and triplet exciton harvesting in PbS CQD PVs. © 2025 Elsevier B.V., All rights reserved. 2025-10-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59349 Title: Natural Antioxidant-Inspired Interfacial Engineering for Stable and High-Performance Perovskite Solar Cells Author(s): Choi, Seongmin; Yong, Taeyeong; Kim, Soo-Kwan; Park, Jin Young; Han, Sanghun; Seo, Gayoung; Kim, Hae Jeong; Ma, Hyeon Soo; Lee, Ju-Hyuck; Ko, Seo-Jin; Moon, Byung Joon; Choi, Jongmin Abstract: Although perovskite solar cells (PSCs) have recently achieved high certified power conversion efficiencies (PCEs), operational instability remains a critical obstacle to commercialization. In particular, superoxide (O2 center dot-) generated at metal-oxide charge-transport layers rapidly decomposes perovskites by deprotonating the organic cations (FA(+) and MA+) and therefore must be suppressed. Nevertheless, under operating illumination, the formation and diffusion of O2 center dot- are unavoidable as long as metal oxides are employed in PSCs. To address this, we introduce the natural antioxidant taurine at the SnO2/FAPbI3 interface to suppress O2 center dot- diffusion via chemical radical quenching. We elucidate the taurine-mediated O2 center dot- quenching mechanism through density functional theory (DFT) calculations supported by experiments. In addition, we find that I2 is concomitantly reduced to I- during the quenching process. This antioxidant interface prevents O2 center dot- induced perovskite decomposition under strongly oxidizing conditions. Moreover, the multifunctional groups of taurine form a chemical bridge between SnO2 and FAPbI3, reducing interfacial defect density, enhancing carrier mobility, and suppressing non-radiative recombination. Consequently, the taurine-buried interface enables an improved PCE with increased open-circuit voltage (VOC) and fill factor (FF), while markedly enhancing the light-soaking and operational stability of PSCs. https://scholar.dgist.ac.kr/handle/20.500.11750/58960 Title: Conjugated Polymer-Driven Compact Crystal Packing and Efficient Charge Transport in Perovskite Quantum Dot Solar Cells Author(s): Yoon, Tae Oh; Alam, Shabaz; Baek, Dohun; Lee, Dongwoon; Na, Hyemi; Cha, Jeongbeom; Jin, Haedam; Lee, Myeoungwon; Li, Meng Qian; Yang, Seoju; Han, Sanghun; Seo, Gayoung; Choi, Jongmin; Jang, Jaeyoung; Lee, Jaewon; Kim, Min Abstract: The stability and performance of perovskite quantum dot (PQD) solar cells are often compromised due to surface defects, phase transitions under ambient conditions, and inefficient charge transport caused by random packing and long-chain insulating ligands. This study introduces a conjugated polymer ligand strategy to simultaneously address these challenges by enhancing both charge transport and nanocrystal packing orientation. Unlike conventional insulating ligands, these conjugated polymers exhibit strong interaction with PQD surfaces while facilitating preferred PQD packing through pi-pi stacking interactions, a mechanism previously unexplored in PQD assemblies. Functionalized with ethylene glycol side chains, these polymers effectively reduce defect density, improve crystallinity, and enhance inter-dot coupling, leading to superior charge transport pathways. As a result, devices incorporating these polymers achieve a significantly improved maximum power conversion efficiency of over 15%, compared to 12.7% for pristine devices, with notable enhancements in short-circuit current density and fill factor. Furthermore, these devices demonstrate exceptional stability, retaining over 85% of their initial efficiency after 850 h. These findings establish conjugated polymer ligands as a dual-functional strategy for passivation and controlled PQD assembly, unlocking new pathways for high-performance and stable PQD solar cells suitable for real-world optoelectronic applications. 2025-09-30T15:00:00Z