Polymer Solar Cell record 14.2% high

게시자: Hyung Min Kim, 2018. 5. 23. 오후 5:57

A Wide Band Gap Polymer with a Deep Highest Occupied Molecular Orbital Level Enables 14.2% Efficiency in Polymer Solar Cells
Sunsun Li et al.

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Ultralong phosphorescence from organic materials

게시자: Hyung Min Kim, 2018. 5. 23. 오후 4:12

Ultralong room temperature phosphorescence from amorphous organic materials toward confidential information encryption and decryption 
Yan Su et al.

Ultralong room temperature phosphorescence (URTP) emitted from pure amorphous organic molecules is very rare. Although a few crystalline organic molecules could realize URTP with long lifetimes (>100 ms), practical applications of these crystalline organic phosphors are still challenging because the formation and maintenance of high-quality crystals are very difficult and complicated. Herein, we present a rational design for minimizing the vibrational dissipation of pure amorphous organic molecules to achieve URTP. By using this strategy, a series of URTP films with long lifetimes and high phosphorescent quantum yields (up to 0.75 s and 11.23%, respectively) were obtained from amorphous organic phosphors without visible fluorescence and phosphorescence under ambient conditions. On the basis of the unique features of URTP films, a new green screen printing technology without using any ink was developed toward confidential information encryption and decryption. This work presents a breakthrough strategy in applying amorphous organic materials for URTP.

Singled out for sequencing

게시자: Hyung Min Kim, 2013. 12. 30. 오후 1:31   [ 2013. 12. 30. 오후 2:14에 업데이트됨 ]

"Method of the Year"

Single-cell genome and transcriptome sequencing methods are generating a fresh wave of biological insights into development, cancer and neuroscience. Kelly Rae Chi reports.

Nature Methods 11, 13–17 (2014)

Biomolecular interactions and tools for their recognition: focus on the quartz crystal microbalance and its diverse surface chemistries and

게시자: Hyung Min Kim, 2013. 12. 27. 오후 11:43

Interactions between molecules are ubiquitous and occur in our bodies, the food we eat, the air we breathe, and myriad additional contexts. Although numerous tools are available for the recognition of biomolecular interactions, such tools are often limited in their sensitivity, expensive, and difficult to modify for various uses. In contrast, the quartz crystal microbalance (QCM) has sub-nanogram detection capabilities, is label-free, is inexpensive to create, and can be readily modified with a number of diverse surface chemistries to detect and characterize diverse interactions. To maximize the versatility of the QCM, scientists need to know available methods by which QCM surfaces can be modified. Therefore, in addition to summarizing the various tools currently used for biomolecular recognition, explicating the fundamental principles of the QCM as a tool for biomolecular recognition, and comparing the QCM with other acoustic sensors, we systematically review the numerous types of surface chemistries—including hydrophobic bonds, ionic bonds, hydrogen bonds, self-assembled monolayers, plasma-polymerized films, photochemistry, and sensing ionic liquids—used to functionalize QCMs for various purposes. We also review the QCM's diverse applications, which include the detection of gaseous species, detection of carbohydrates, detection of nucleic acids, detection of non-enzymatic proteins, characterization of enzymatic activity, detection of antigens and antibodies, detection of cells, and detection of drugs. Finally, we discuss the ultimate goals of and potential barriers to the development of future QCMs

Graphical abstract: Biomolecular interactions and tools for their recognition: focus on the quartz crystal microbalance and its diverse surface chemistries and applications

Chem. Soc. Rev., 2012,41, 1947-1971

Aggregation-Induced Enhancement Effect of Gold Nanoparticles on Triplet Excited State

게시자: Hyung Min Kim, 2013. 12. 27. 오후 11:32

Remarkable optical properties are posed with gold nanoparticles (AuNPs) due to the excitation of localized surface plasmon resonances, which makes AuNPs affect strongly both the ground state and the excited state of adjacent organic molecules. Compared with the ground state, the effect of AuNPs on excited state of organic molecules is not always fully understood. Here, we performed transient UV–vis absorption experiments to monitor the triplet excited state formation of three cationic dyes and one anionic dye in the presence of two types of gold nanoparticles: the citrate-stabilized AuNPs and ATP-protected AuNPs. It is found that the three cationic dyes can cause efficient aggregation of citrate-stabilized AuNPs, leading to AuNPs aggregates with varied size, whereas the ATP-protected AuNPs can be sustained in the monodispersed state. By comparing the circumstances of aggregated AuNPs and monodispersed AuNPs, we demonstrate that the enhancement effect on triplet excited state formation results from the aggregation of gold nanoparticles and depends on the aggregation size. These findings reveal the aggregation induced plasmon field interaction of AuNPs with excited state population dynamics and may enable new applications of aggregated metal nanoparticles, where aggregates can serve as stronger plasmonic nanoantennas.

J. Phys. Chem. C, 2013, 117 (51), pp 27088–27095

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Tunable lifetime multiplexing using luminescent nanocrystals

게시자: Hyung Min Kim, 2013. 12. 27. 오후 11:27   [ 2013. 12. 27. 오후 11:28에 업데이트됨 ]

 Optical multiplexing plays an important role in applications such as optical data storage1, document security2, molecular probes3, 4 and bead assays for personalized medicine5. Conventional fluorescent colour coding is limited by spectral overlap and background interference, restricting the number of distinguishable identities. Here, we show that tunable luminescent lifetimes τ in the microsecond region can be exploited to code individual upconversion nanocrystals. In a single colour band, one can generate more than ten nanocrystal populations with distinct lifetimes ranging from 25.6 µs to 662.4 µs and decode their well-separated lifetime identities, which are independent of both colour and intensity. Such ‘τ-dots’ potentially suit multichannel bioimaging, high-throughput cytometry quantification, high-density data storage, as well as security codes to combat counterfeiting. This demonstration extends the optical multiplexing capability by adding the temporal dimension of luminescent signals, opening new opportunities in the life sciences, medicine and data security.
Lifetime tuning scheme and time-resolved confocal images for NaYF4:Yb,Tm upconversion nanocrystals.
Nature Photonics 8, 32–36 (2014)

Intellectual Freedom in Academic Scientific Research under Threat

게시자: Hyung Min Kim, 2013. 5. 19. 오후 3:23   [ 2013. 5. 19. 오후 4:20에 업데이트됨 ]

It is because scientific research in our universities is under threat! The freedom to pursue in untrammeled fashion research prompted by intellectual curiosity is being increasingly restricted by the paladins of the research councils. Public bodies that fund academic research in the UK now tend to emphasize the rerceived practical importance of the scientific research that they decide to support financially.

Eigen factor (EF) of journals

게시자: Hyung Min Kim, 2013. 5. 5. 오후 2:51

The Eigenfactor score, developed by Jevin West and Carl Bergstrom at the University of Washington, is a rating of the total importance of a scientific journal. Journals are rated according to the number of incoming citations, with citations from highly ranked journals weighted to make a larger contribution to the eigenfactor than those from poorly ranked journals. As a measure of importance, the Eigenfactor score scales with the total impact of a journal. All else equal, journals generating higher impact to the field have larger Eigenfactor scores.

Eigenfactor scores and Article Influence scores are calculated by, where they can be freely viewed. The Eigenfactor score is intended to measure the importance of a journal to the scientific community, by considering the origin of the incoming citations, and is thought to reflect how frequently an average researcher would access content from that journal. However, the Eigenfactor score is influenced by the size of the journal, so that the score doubles when the journal doubles in size (measured as published articles per year). The Article Influence score measures the average influence of articles in the journal, and is therefore comparable to the ISI impact factor.

Plasmonic Nanobubbles as Transient Vapor Nanobubbles Generated around Plasmonic Nanoparticles

게시자: Hyung Min Kim, 2013. 4. 24. 오후 5:43

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We have used short laser pulses to generate transient vapor nanobubbles around plasmonic nanoparticles. The photothermal, mechanical, and optical properties of such bubbles were found to be different from those of plasmonic nanoparticle and vapor bubbles, as well. This phenomenon was considered as a new complex nanosystem—plasmonic nanobubble (PNB). Mechanical and optical scattering properties of PNB depended upon the nanoparticle surface and heat capacity, clusterization state, and the optical pulse length. The generation of the PNB required much higher laser pulse fluence thresholds than the explosive boiling level and was characterized by the relatively high lower threshold of the minimal size (lifetime) of PNB. Optical scattering by PNB and its diameter (measured as the lifetime) has been varied with the fluence of laser pulse, and this has demonstrated the tunable nature of PNB.

Nanoclustered Gold Honeycombs for Surface-Enhanced Raman Scattering

게시자: Hyung Min Kim, 2013. 2. 13. 오전 7:15

A honeycomb-shaped gold substrate was developed for surface-enhanced Raman imaging (SERI). The honeycombs are composed of clusters of 50–70 nm gold nanoparticles and exhibit high Raman enhancement efficiency. An average surface enhancement factor (ASEF) of 1.7 × 10
6 was estimated for a monolayer of l-cysteine molecules adsorbed to gold via a thiol linkage. The presence of a linear relationship in the low concentration region was observed in SERI detection of malachite green isothiocyanate (MGITC). These results together with the high reproducibility and simple and cost-effective fabrication of this substrate suggest that it has utility for applications of surface-enhanced Raman scattering (SERS) in quantitative diagnoses and analyte detection.

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