48 research outputs found
Highly efficient aligned AgInS2 quantum dots films conjugated with self-assembled block copolymer
No full textMethoxy-Functionalized Triarylamine-Based Hole-Transporting Polymers for Highly Efficient and Stable Perovskite Solar Cells
No full textThe hole-transporting layer is an essential component in a perovskite solar cell (PSC) and plays a key role in controlling both power conversion efficiency (PCE) and stability. Here, we report a new hole-transporting material (HTM), methoxy group-containing poly(triarylamine) (PTAA) (CH3O-PTAA), for efficient PSCs with improved thermal stability. As compared to commonly used PTAA (CH3-PTAA), CH3O-PTAA exhibits enhanced doping ability and stability under thermal stress. With CH3O-PTAA, (FAPbI(3))(0.85)(MAPbBr(3))(0.15)-based PSCs show high PCEs over 20%, comparable to those of CH3-PTAA devices. More importantly, better long-term thermal stability with only 3% reduction from the initial PCE (6.1% reduction on average) has been achieved for encapsulated PSCs with CH3O-PTAA than that of PSCs with CH3-PTAA under dark storage conditions (ISOS-D-3) of 85 degrees C and 85% relative humidity (RH) over 1000 h. Detailed studies have been conducted to reveal the strong correlation between the doping behavior of HTMs and the performance of PSCs, which provide useful guidelines for the design of new HTMs for efficient and stable PSCs.
Intrinsically Stretchable, Green Solvent-Processed, and Efficient Polymer Solar Cells Enabled by Hydrophilic Flexible Spacer-Incorporating Polymer Donors
No full textIntrinsically-stretchable, non-halogenated solvent processed polymer solar cells enabled by hydrophilic flexible spacer-incorporated polymers
No full textEFFICIENT, GREEN-SOLVENT PROCESSED, AND MECHANICALLY ROBUST POLYMER SOLAR CELLS ENABLED BY HYDROPHILIC SPACER-INCORPORATED POLYMER DONORS
No full text고분자 태양전지의 효율과 기계적 내구성 향상을 위한 공액 고분자 및 올리고머 소재 개발
No full text학위논문(박사) - 한국과학기술원 : 생명화학공학과, 2025.2,[vi, 119 p. :]Polymer solar cells (PSCs) based on conjugated organic materials have advantages such as solution processability, light weight, and flexibility. Thanks to these properties, PSCs have evolved from simple flexible devices to next-generation stretchable devices that can deform in all directions and, which are attractive as self-powered sources for wearable electronics. However, traditional conjugated organic materials designed to optimize the performance of PSCs lack sufficient mechanical durability to maintain stable optical and electrical properties under mechanical stress for long-term operation, making them challenging to use as photoactive layers in stretchable devices. Therefore, new strategies for designing photoactive materials are needed to realize high-performance and mechanically durable PSCs.
This dissertation aims to address the aforementioned issues by developing novel photoactive materials with excellent opto-electrical properties and mechanical stretchability. Chapter 1 introduces the working principles of PSCs and strategies to enhance their mechanical durability. Chapter 2 discusses the development of high-performance and eco-friendly processable PSCs with excellent mechanical durability, achieved by introducing a hydrophilic ethylene glycol unit into conjugated polymer donors. Specifically, by controlling the miscibility between the polymer donor and non-fullerene small molecule acceptor (NFSMA), excessive crystallization of the small molecule materials was suppressed, thereby alleviating the brittleness of the photoactive layer film and enhancing mechanical stretchability. Chapter 3 describes the synthesis of a mechanically robust naphthalene diimide (NDI)-based conjugated polymers and their use as an additive in NFSMA-based photoactive layers to produce an intrinsically stretchable PSCs. In particular, by controlling the critical molecular weight (Mc) of the additive polymer, P(NDI2OD-TCVT), a greater degree of tie molecules and chain entanglements was developed, resulting in optimal stretchability in the ternary photoactive layer. In Chapter 4, we discuss the research to enhance the performance and stability of PSCs through the development of oligomerized small molecule acceptors (OSMAs) with extended main chains, synthesized by covalently bonding monomeric NFSMAs. In addition, the effects of molecular size and dispersity of these oligomers on material properties and device performance were systematically investigated.
I hope that the results of these studies will serve as a basis for designing new photoactive materials to improve the performance and mechanical durability of PSCs.한국과학기술원 :생명화학공학과
비공유결합으로 주쇄가 연결된 단분자 전자 받개에서 말단기가 결정성, 광학적 및 전기적 특성 그리고 유기태양전지 성능에 미치는 영향에 대한 연구
No full text학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2021.2,[iii, 29 p. :]In this contribution, I investigated the effects of end-groups in Noncovalently-fused backbone small molecule electron acceptors on crystallinity, optoelectrical properties and performance of organic solar cells. The small molecule electron acceptors were synthesized with different end-groups and called Triazole-IC, Triazole-ICBr and Triazole-IC2Cl whose end-groups were hydrogen, monobromine and dichlorine atom. Introducing halogen atoms were expected to develop dipole moment within molecular structure which increase intermolecular interaction between them and enhance optoelectrical properties. The Triazole-IC4Cl showed improved molecular properties among other acceptors and those directly influenced on the performance of the organic solar cell devices. As a result, the device fabricated with Triazole-IC4Cl acceptor enable the maximum power conversion efficiency (PCE) of 9.22%. Thus, noncovalent interaction strategy can be effective approach to design small molecule acceptors.한국과학기술원 :생명화학공학과
INTRINSICALLY-STRETCHABLE AND NON-HALOGENATED SOLVENT PROCESSED POLYMER SOLAR CELLS ENABLED BY HYDROPHILIC FLEXIBLE SPACER-INCORPORATING POLYMERS
No full textTherapeutic effect of magnesium lithospermate B on neointimal formation after balloon-induced vascular injury
No full textVascular smooth muscle cell (VSMC) proliferation and migration in response to platelet-derived growth factor (PDGF) play an important role in the development of atherosclerosis and restenosis. Recent evidence indicates that PDGF increases intracellular levels of reactive oxygen species in VSMCs and that both PDGF-induced VSMC proliferation and migration are reactive oxygen species-dependent. Danshen is a representative oriental medicine used for the treatment of vascular disease. Previously, we reported that magnesium lithospermate B, an active component of Danshen, is a potent antioxidant. Thus we investigated the therapeutic potential of magnesium lithospermate B in neointimal formation after carotid artery injury in rats along with its effects on the PDGF signaling pathway for stimulating VSMC proliferation and migration in vitro. PDGF is dimeric glycoprotein composed of two A or two B chains. In this study, we used PDGF-BB, which is one of the isoforms of PDGF (i.e., PDGF-AA, PDGF-BB, and PDGF-AB). Our results demonstrated that magnesium lithospermate B directly scavenged reactive oxygen species in a xanthine/xanthine oxidase system and reduced PDGF-BB-induced intracellular reactive oxygen species generation in VSMCs. In a rat carotid artery balloon injury model, magnesium lithospermate B treatment (10 mg/kg/day, i.p) showed a significant effect on the prevention of neointimal formation compared with vehicle treatment. In cultured VSMCs, magnesium lithospermate B significantly attenuated PDGF-BB-induced cell proliferation and migration as measured by 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2-tetrazolium bromide (MTT) assay and transwell migration assays, respectively. Further, magnesium lithospermate B inhibited PDGF-BB-induced phosphorylation of phospatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways by scavenging reactive oxygen species. Together, these data indicated that magnesium lithospermate 13, a potent reactive oxygen species scavenger, prevented both injury-induced neointimal formation in vivo and PDGF-BB-induced VSMC proliferation and migration in vitro, suggesting that magnesium lithospermate B may be a promising agent to prevent atherosclerosis and restenosis following angioplasty. (c) 2008 Elsevier B.V. All rights reserved
