Developing the information-seeking behavior scale for undergraduates

Purpose: The aim of this paper is to develop a standardized and reliable measurement tool for assessing information-seeking behavior of undergraduate students.Design/methodology/approach: Based on information literacy and information-seeking behavior theories, expert advice and students' interview, items of undergraduates' informationseeking behavior indicators were selected. With the analysis of homogeneity reliability, item analysis and factor analysis, this study constructs an assessment system to evaluate reliability and validity of the scale.Findings: The information-seeking behavior scale for undergraduates has divided undergraduates' information-seeking behavior into seven dimensions, which include 46 items. The reliability analysis of Cronbach's α was 0.910, and the coefficient of split-half reliability was0.817. The results of factor analysis showed that Kaiser-Meyer-Olkin(KMO) was 0.864,which indicates 55.536% of the total variation could be explained by the above seven dimensions.Research limitations: Due to a small sample size and limited sample distribution, further research need be conducted in an expanded sample size in order to explore the application scope of this evaluation system; in addition, the stability of the scale also need be confirmed.Practical implications: The paper sets up an information-seeking behavior evaluation system for undergraduates and explores the characteristics of their information-seeking behavior.This study provides guidance for the development of future information literacy education and the improvement of the information literacy level of undergraduates.Originality/value: An information-seeking behavior scale for undergraduates has been developed, which comprehensively covers information need, information source, information evaluation, information retrieval, information management, information utilization and information morality. The scale is proved to have good reliability, validity, popularity anddiscrimination that it is qualified to be an assessment tool of information-seeking behavior for Chinese undergraduates.

An initial study of information seeking behavior of researchers as faculty/student team members

Purpose:This study was carried out to uncover the characteristics of information seeking behavior of researchers as faculty/student team members.Design/methodology/approach:An inventory encompassing 6 dimensions of information seeking behavior was developed:Information awareness,information acquisition,information evaluation,information organization and management,information utilization and information ethics.Data was collected on 306 respondents from 52 faculty/student teams in Central South University in China and analyzed using SPSS 18.0 software.Findings:Significant differences were found among researchers with different genders in information awareness and in different academic disciplines in information acquisition and information utilization.The survey shows the characteristics of information seeking behavior of different gender groups and different teams:1) male participants got higher scores in all of the 6 dimensions of information seeking behavior;2) small teams performed best,followed by middle-sized teams and large teams;3) faculty/doctoral student teams possessed better information seeking skills than faculty/master’s student teams or faculty/doctoral and master’s student teams:4) medical teams achieved the highest level in all of the 6 dimensions of information seeking behavior,whereas natural science teams the lowest level.Medical and engineering teams were rated higher than other teams in information acquisition and information utilization.Research limitations:The small population size and doctoral students accounting for only a small portion of the respondents in the sample limit the generalization of our findings.Practical implications:The findings of this study have some implications for research and practice,especially for educational institutions,library science and information literacy training.Originality/value:This paper is the first to describe and analyze the characteristics of information seeking behavior of researchers as faculty/student team members.

Utilizing morpholine for purely organic room temperature phosphors

In this article,morpholine,a non-conjugated heterocycle,is embedded intoπsystem to construct single-component organic room temperature phosphorescence(RTP)luminogens.The effect of morpholine on intermolecular interaction,crystal packing modes,and RTP performance is investigated systematically.The experimental and theoretical calculation results illustrate the versatility of morpholine in promoting the n-π*transition and intensifying the intermolecular interactions,which not only enhances the generation of triplet excitons,but also suppresses the nonradiative decay of triplet excitons.Impressively,TMPh containing three morpholine units shows an ultralong lifetime of 1.03 s and a visible afterglow up to 10 s.The unique dual delayed emission and long afterglow property allow potential application of morpholine derivatives in data encryption,and the time-dependent color change of afterglow emission is realized after removing the excitation source,providing a high-level data security.This article provides a new perspective for the design of purely organic RTP system without utilization of metal,or even any heavy atoms.

Tailoring Excited State Properties and Energy Levels Arrangement via Subtle Structural Design on D-π-A Materials

The donor-n-conjugated-acceptor （D-n-A） structure is an important design for the luminescent materials be- cause of its diversity in the selections of donor, n-bridge and acceptor groups. Herein, we demonstrate two examples of D-^-A structures capable to finely modulate the excited state properties and arrangement of energy levels, TPA-AN-BP and CZP-AN-BP, which possess the same acceptor and n-bridge but different donor. The investigation of their photophysical properties and DFT calculation revealed that the D-n-A structure with proper donor, n-bridge and acceptor can result in separation of frontier molecular orbitals on the corresponding donor and acceptor with an obvious overlap on the n-bridge, resulting in a hybridized local and charge-transfer （HLCT） excited state with high photoluminescent （PL） efficiencies. Meanwhile, their singlet and triplet states are arranged on corresponding moie- ties with large energy gap between T2 and T1, and a small energy gap between S1 and T2, which favor the reverse intersystem crossing （RISC） from high-lying triplet levels to singlet levels. As a result, the sky-blue emission non-doped OLED based on the TPA-AN-BP reached maximum external quantum efficiency （EQE） of 4.39% and a high exciton utilization efficiency （EUE） of 77%. This study demonstrates a new strategy to construct highly effi- cient OLED materials.

超高效率的深蓝光蒽基发光材料:设计、合成、光物理与电致发光机制

有机电致发光器件(OLED)因其超轻薄和易于实现柔性等优点而成为全彩色显示领域的研究热点.开发高性能、低成本的深蓝光荧光发光材料对满足未来8K电视高品质显示的超高色域要求至关重要.在多环芳香烃中,蒽基团具备高荧光量子效率(PLQY)和良好的载流子传输能力,而被广泛应用于深蓝光发光材料的构建.本文基于蒽核心,利用外围配体基团调控分子构型,合成出了高性能发光材料2M-ph-pCzAnBzt和2M-pCzAnBzt.特别是采用2M-ph-pCzAnBzt所制备的非掺杂发光层结构的器件,外量子效率超过10%,色度坐标CIEy值<0.06,超过NTSC标准.本文创新性地提出高能反向系间窜越与三重态-三重态湮灭上转换协同作用机制,并结合量化计算分析、敏化实验研究和纳秒瞬态吸收光谱分析予以验证,为解决高效率深蓝光荧光OLED缺乏的瓶颈问题开辟了一条新的技术路线.

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5-d]Imidazole-Pyrene Molecule

Organic light-emitting diodes(OLEDs),which have been recently utilized in some flat-panel display screens such as mobile phones and televisions,show many merits,including light weight,high flexibility,energy preservation,and so forth,and are considered the next-generation displays and solid-state lightings.Blue-emitting materials that can be applied in nondoped OLEDs with little efficiency roll-offs at high brightness are of great importance.Here,a highly efficient,blue-emitting material,9-phenyl10-(4-(pyren-1-yl)phenyl)-9H-pyreno[4,5-d]imidazole(PyPI-Py),is achieved using pyrene[4,5-d]imidazole and pyrene as the weak electron donor and electron acceptor,respectively.The nondoped blue OLED exhibits excellent performance with a maximum brightness of 75,687 cd m^(−2),a maximum current efficiency of 13.38 cd A−1,and a maximum external quantum efficiency(ηext)of 8.52%.Moreover,theηext is maintained at 8.35%and 8.05%at a brightness of 10,000 and 50,000 cd m^(−2),respectively,displaying extremely small efficiency roll-offs of 2.0%and 5.5%.The device characteristics are among the highest values for nondoped blue OLEDs and correspond to the best performance obtained for nondoped pyrene-based blue OLEDs.The superior performance is attributed to the proper donor–acceptor design strategy which results in a quasi-equivalent hybrid local and charge-transfer excited state with the maximum generation of an 82%fraction of singlet excitons.

Preparation and electronic characteristics of anionic perylene bisimide films

Neutral perylene bisimides(PBI) are well-known n-type organic semiconductors, with number of challenging electronic properties in their neutral and reduced states. We report the characteristic electronic properties of PBI anionic films. We unexpectedly discovered that pristine PBI dianion film showed p-type character, while oxidized dianion film(dominant neutral state with few radical anions) showed normal n-type semiconductor character based on Seebeck effect measurements. Both kinds of films exhibit high electrical conductivity with a potential for thermoelectric applications. The mechanism of polarity reversal is proposed.

Pure-Blue Fluorescence Molecule for Nondoped Electroluminescence with External Quantum Efficiency Approaching 13%

A pure-blue light-emitting material is one of the key components in the preparation of organic lightemitting diode(OLED)displays.Although highefficiency blue OLEDs have been realized in thermally activated delayed fluorescence(TADF)materials,they need to be dispersed into suitable hostmaterials.Hence,exploring efficient nondoped,pure-blue luminous molecules is important.