Browsing by Author "Wang Y."

Now showing 1 - 15 of 15

Open Access
Adolescent risk-taking as a function of prenatal cocaine exposure and biological sex
(Elsevier Inc., 2014) Allen, J. W. P.; Bennett, D. S.; Carmody, D. P.; Wang Y.; Lewis, M.
Objective: To examine the effects of prenatal cocaine exposure and biological sex on adolescent risk-taking while controlling for early environmental risk. Methods: Adolescents (n. = 114, mean age. = 16) were grouped according to high and low risk-taking propensity as measured by the Balloon Analogue Risk Task (BART). Prenatal cocaine exposure was assessed at birth, while environmental risk was assessed at three points during early childhood. Results: A binary regression analysis indicated that males were 3.5 times more likely than females to be high risk-takers. Biological sex and prenatal cocaine exposure interacted such that exposed males were most likely to be high risk-takers while exposed females were the least likely to be high risk-takers. This pattern held after controlling for prenatal alcohol exposure and early environmental risk. Early environmental risk did not predict adolescent risk-taking. Conclusions: These findings complement and extend earlier research demonstrating that prenatal cocaine exposure interacts with biological sex in domains related to inhibitory control, emotion regulation, antisocial behavior, and health risk behaviors during preadolescence.
Open Access
Blue liquid lasers from solution of CdZnS/ZnS ternary alloy quantum dots with quasi ‐ continuous pumping
(Wiley - VCH Verlag GmbH & Co. KGaA, 2015) Wang Y.; Leck K.S.; Ta, V. D.; Chen R.; Nalla, V.; Gao, Y.; He T.; Demir, Hilmi Volkan; Sun, H.
A blue (ca. 440 nm) liquid laser with an ultra‐low threshold through which quasi‐continuous wave pumping is accessible is achieved by engineering unconventional ternary CdZnS/ZnS alloyed‐core/shell QDs. Such an achievement is enabled by exploiting the novel gain media with minimal defects, suppressed Auger recombination, and large gain cross‐section in combination with high‐quality‐factor whispering gallery mode resonators.
Open Access
Chiral ceramic nanoparticles and peptide catalysis
(American Chemical Society, 2017) Jiang S.; Chekini, M.; Qu, Z.-B.; Wang Y.; Yeltik A.; Liu, Y.; Kotlyar, A.; Zhang, T.; Li, B.; Demir, Hilmi Volkan; Kotov, N. A.
The chirality of nanoparticles (NPs) and their assemblies has been investigated predominantly for noble metals and II-VI semiconductors. However, ceramic NPs represent the majority of nanoscale materials in nature. The robustness and other innate properties of ceramics offer technological opportunities in catalysis, biomedical sciences, and optics. Here we report the preparation of chiral ceramic NPs, as represented by tungsten oxide hydrate, WO3-x·H2O, dispersed in ethanol. The chirality of the metal oxide core, with an average size of ca. 1.6 nm, is imparted by proline (Pro) and aspartic acid (Asp) ligands via bio-to-nano chirality transfer. The amino acids are attached to the NP surface through C-O-W linkages formed from dissociated carboxyl groups and through amino groups weakly coordinated to the NP surface. Surprisingly, the dominant circular dichroism bands for NPs coated by Pro and Asp are different despite the similarity in the geometry of the NPs; they are positioned at 400-700 nm and 500-1100 nm for Pro- and Asp-modified NPs, respectively. The differences in the spectral positions of the main chiroptical band for the two types of NPs are associated with the molecular binding of the two amino acids to the NP surface; Asp has one additional C-O-W linkage compared to Pro, resulting in stronger distortion of the inorganic crystal lattice and greater intensity of CD bands associated with the chirality of the inorganic core. The chirality of WO3-x·H2O atomic structure is confirmed by atomistic molecular dynamics simulations. The proximity of the amino acids to the mineral surface is associated with the catalytic abilities of WO3-x·H2O NPs. We found that NPs facilitate formation of peptide bonds, leading to Asp-Asp and Asp-Pro dipeptides. The chiroptical activity, chemical reactivity, and biocompatibility of tungsten oxide create a unique combination of properties relevant to chiral optics, chemical technologies, and biomedicine.
Open Access
Green stimulated emission boosted by nonradiative resonant energy transfer from blue quantum dots
(American Chemical Society, 2016) Gao, Y.; Yu, G.; Wang Y.; Dang C.; Sum, T. C.; Sun, H.; Demir, Hilmi Volkan
Thanks to their tunability and versatility, the colloidal quantum dots (CQDs) made of II-VI semiconductor compound offer the potential to bridge the "green gap" in conventional semiconductors. However, when the CQDs are pumped to much higher initial excitonic states compared to their bandgap, multiexciton interaction is enhanced, leading to a much higher stimulated emission threshold. Here, to circumvent this drawback, for the first time, we show a fully colloidal gain in green enabled by a partially indirect pumping approach assisted by Förster resonance energy transfer process. By introducing the blue CQDs as exciton donors, the lasing threshold of the green CQDs, is reduced dramatically. The blue CQDs thus serve as an energy-transferring buffer medium to reduce excitation energy from pumping photons in a controlled way by injecting photoinduced excitons into green CQDs. Our newly developed colloidal pumping scheme could enable efficient CQD lasers of full visible colors by a single pump source and cascaded exciton transfer. This would potentially pave the way for an efficient multicolor laser for lighting and display applications.
Open Access
Influence of gold-silica nanoparticles on the performance of small-molecule bulk heterojunction solar cells
(Elsevier BV * North-Holland, 2015) Xu, X.; Kyaw, A. K. K.; Peng, B.; Xiong, Q.; Demir, Hilmi Volkan; Wang Y.; Wong, T. K. S.; Sun, X. W.
Light trapping by gold (Au)-silica nanospheres and nanorods embedded in the active layer of small-molecule (SM) organic solar cell has been systematically compared. Nanorod significantly outperforms nanosphere because of more light scattering and higher quality factor for localized surface plasmon resonance (LSPR) triggered by nanorods. The optimum concentration of nanorod was characterized by charge carrier transport and morphology of the active layers. At optimum nanorod concentration, almost no change in the morphology of the active layer reveals that LSPR and scattering effects rather than the morphology are mainly responsible for the enhanced power conversion efficiency. In addition, the preliminary lifetime studies of the SM solar cells with and without Au-silica nanorods were conducted by measuring the current density-voltage characteristics over 20 days. The results show that plasmonic device with nanorods has no adverse impact on the device stability
Open Access
An integrated map of genetic variation from 1,092 human genomes
(Nature Publishing Group, 2012) Altshuler, D.M.; Durbin, R.M.; Abecasis G.R.; Bentley, D.R.; Chakravarti, A.; Clark, A.G.; Donnelly P.; Eichler, E.E.; Flicek P.; Gabriel, S.B.; Gibbs, R.A.; Green, E.D.; Hurles, M.E.; Knoppers, B.M.; Korbel J.O.; Lander, E.S.; Lee, C.; Lehrach H.; Mardis, E.R.; Marth G.T.; McVean G.A.; Nickerson, D.A.; Schmidt J.P.; Sherry, S.T.; Wang, J.; Wilson, R.K.; Dinh H.; Kovar, C.; Lee, S.; Lewis L.; Muzny, D.; Reid J.; Wang, M.; Fang X.; Guo X.; Jian, M.; Jiang H.; Jin X.; Li G.; Li J.; Li Y.; Li, Z.; Liu X.; Lu, Y.; Ma X.; Su, Z.; Tai, S.; Tang, M.; Wang, B.; Wang G.; Wu H.; Wu, R.; Yin, Y.; Zhang W.; Zhao J.; Zhao, M.; Zheng X.; Zhou, Y.; Gupta, N.; Clarke L.; Leinonen, R.; Smith, R.E.; Zheng-Bradley X.; Grocock, R.; Humphray, S.; James, T.; Kingsbury, Z.; Sudbrak, R.; Albrecht, M.W.; Amstislavskiy V.S.; Borodina, T.A.; Lienhard, M.; Mertes F.; Sultan, M.; Timmermann, B.; Yaspo, M.-L.; Fulton L.; Fulton, R.; Weinstock G.M.; Balasubramaniam, S.; Burton J.; Danecek P.; Keane, T.M.; Kolb-Kokocinski, A.; McCarthy, S.; Stalker J.; Quail, M.; Davies, C.J.; Gollub J.; Webster, T.; Wong, B.; Zhan, Y.; Auton, A.; Yu F.; Bainbridge, M.; Challis, D.; Evani, U.S.; Lu J.; Nagaswamy, U.; Sabo, A.; Wang Y.; Yu J.; Coin L.J.M.; Fang L.; Li Q.; Li, Z.; Lin H.; Liu, B.; Luo, R.; Qin, N.; Shao H.; Wang, B.; Xie, Y.; Ye, C.; Yu, C.; Zhang F.; Zheng H.; Zhu H.; Garrison, E.P.; Kural, D.; Lee W.-P.; Fung Leong W.; Ward, A.N.; Wu J.; Zhang, M.; Griffin L.; Hsieh, C.-H.; Mills, R.E.; Shi X.; Von Grotthuss, M.; Zhang, C.; Daly, M.J.; Depristo, M.A.; Banks, E.; Bhatia G.; Carneiro, M.O.; Del Angel G.; Genovese G.; Handsaker, R.E.; Hartl, C.; McCarroll, S.A.; Nemesh J.C.; Poplin, R.E.; Schaffner, S.F.; Shakir, K.; Yoon, S.C.; Lihm J.; Makarov V.; Jin H.; Kim W.; Cheol Kim, K.; Rausch, T.; Beal, K.; Cunningham F.; Herrero J.; McLaren W.M.; Ritchie G.R.S.; Gottipati, S.; Keinan, A.; Rodriguez-Flores J.L.; Sabeti P.C.; Grossman, S.R.; Tabrizi, S.; Tariyal, R.; Cooper, D.N.; Ball, E.V.; Stenson P.D.; Barnes, B.; Bauer, M.; Keira Cheetham, R.; Cox, T.; Eberle, M.; Kahn, S.; Murray L.; Peden J.; Shaw, R.; Ye, K.; Batzer, M.A.; Konkel, M.K.; Walker J.A.; MacArthur, D.G.; Lek, M.; Herwig, R.; Shriver, M.D.; Bustamante, C.D.; Byrnes J.K.; De La Vega F.M.; Gravel, S.; Kenny, E.E.; Kidd J.M.; Maples, B.K.; Moreno-Estrada, A.; Zakharia F.; Halperin, E.; Baran, Y.; Craig, D.W.; Christoforides, A.; Homer, N.; Izatt, T.; Kurdoglu, A.A.; Sinari, S.A.; Squire, K.; Xiao, C.; Sebat J.; Bafna V.; Ye, K.; Burchard, E.G.; Hernandez, R.D.; Gignoux, C.R.; Haussler, D.; Katzman, S.J.; James Kent W.; Howie, B.; Ruiz-Linares, A.; Dermitzakis, E.T.; Lappalainen, T.; Devine, S.E.; Liu X.; Maroo, A.; Tallon L.J.; Rosenfeld J.A.; Michelson L.P.; Min Kang H.; Anderson P.; Angius, A.; Bigham, A.; Blackwell, T.; Busonero F.; Cucca F.; Fuchsberger, C.; Jones, C.; Jun G.; Li Y.; Lyons, R.; Maschio, A.; Porcu, E.; Reinier F.; Sanna, S.; Schlessinger, D.; Sidore, C.; Tan, A.; Kate Trost, M.; Awadalla P.; Hodgkinson, A.; Lunter G.; Marchini J.L.; Myers, S.; Churchhouse, C.; Delaneau O.; Gupta-Hinch, A.; Iqbal, Z.; Mathieson I.; Rimmer, A.; Xifara, D.K.; Oleksyk, T.K.; Fu, Y.; Liu X.; Xiong, M.; Jorde L.; Witherspoon, D.; Xing J.; Browning, B.L.; Alkan C.; Hajirasouliha I.; Hormozdiari F.; Ko, A.; Sudmant P.H.; Chen, K.; Chinwalla, A.; Ding L.; Dooling, D.; Koboldt, D.C.; McLellan, M.D.; Wallis J.W.; Wendl, M.C.; Zhang Q.; Tyler-Smith, C.; Albers, C.A.; Ayub Q.; Chen, Y.; Coffey, A.J.; Colonna V.; Huang, N.; Jostins L.; Li H.; Scally, A.; Walter, K.; Xue, Y.; Zhang, Y.; Gerstein, M.B.; Abyzov, A.; Balasubramanian, S.; Chen J.; Clarke, D.; Fu, Y.; Habegger L.; Harmanci, A.O.; Jin, M.; Khurana, E.; Jasmine Mu X.; Sisu, C.; Degenhardt J.; Stütz, A.M.; Keira Cheetham, R.; Church, D.; Michaelson J.J.; Blackburne, B.; Lindsay, S.J.; Ning, Z.; Frankish, A.; Harrow J.; Mu X.J.; Fowler G.; Hale W.; Kalra, D.; Barker J.; Kelman G.; Kulesha, E.; Radhakrishnan, R.; Roa, A.; Smirnov, D.; Streeter I.; Toneva I.; Vaughan, B.; Ananiev V.; Belaia, Z.; Beloslyudtsev, D.; Bouk, N.; Chen, C.; Cohen, R.; Cook, C.; Garner J.; Hefferon, T.; Kimelman, M.; Liu, C.; Lopez J.; Meric P.; O'Sullivan, C.; Ostapchuk, Y.; Phan L.; Ponomarov, S.; Schneider V.; Shekhtman, E.; Sirotkin, K.; Slotta, D.; Zhang H.; Barnes, K.C.; Beiswanger, C.; Cai H.; Cao H.; Gharani, N.; Henn, B.; Jones, D.; Kaye J.S.; Kent, A.; Kerasidou, A.; Mathias, R.; Ossorio P.N.; Parker, M.; Reich, D.; Rotimi, C.N.; Royal, C.D.; Sandoval, K.; Su, Y.; Tian, Z.; Tishkoff, S.; Toji L.H.; Via, M.; Wang Y.; Yang H.; Yang L.; Zhu J.; Bodmer W.; Bedoya G.; Ming, C.Z.; Yang G.; Jia You, C.; Peltonen L.; Garcia-Montero, A.; Orfao, A.; Dutil J.; Martinez-Cruzado J.C.; Brooks L.D.; Felsenfeld, A.L.; McEwen J.E.; Clemm, N.C.; Duncanson, A.; Dunn, M.; Guyer, M.S.; Peterson J.L.; Lacroute P.
By characterizing the geographic and functional spectrum of human genetic variation, the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. Here we describe the genomes of 1,092 individuals from 14 populations, constructed using a combination of low-coverage whole-genome and exome sequencing. By developing methods to integrate information across several algorithms and diverse data sources, we provide a validated haplotype map of 38 million single nucleotide polymorphisms, 1.4 million short insertions and deletions, and more than 14,000 larger deletions. We show that individuals from different populations carry different profiles of rare and common variants, and that low-frequency variants show substantial geographic differentiation, which is further increased by the action of purifying selection. We show that evolutionary conservation and coding consequence are key determinants of the strength of purifying selection, that rare-variant load varies substantially across biological pathways, and that each individual contains hundreds of rare non-coding variants at conserved sites, such as motif-disrupting changes in transcription-factor-binding sites. This resource, which captures up to 98% of accessible single nucleotide polymorphisms at a frequency of 1% in related populations, enables analysis of common and low-frequency variants in individuals from diverse, including admixed, populations. © 2012 Macmillan Publishers Limited. All rights reserved.
Open Access
Manipulating optical properties of ZnO/Ga: ZnO core-shell nanorods via spatially tailoring electronic bandgap
(Wiley-VCH Verlag, 2015) Zhao, X.; Gao, Y.; Wang Y.; Demir, Hilmi Volkan; Wang, S.; Sun, H.
Enhancing optical and electrical properties of ZnO nanostructures via surface doping is demonstrated by Ga:ZnO–ZnO core–shell nanorods, which are grown by a genetic two-step method. Low-temperature photoluminescence and X-ray photoelectron spectroscopy prove the n + shell significantly suppresses the surface-related recombination by spatially modulating the electronic band structure. The study provides a significant physical insight in designing optoelectronic devices.
Open Access
Observation of polarized gain from aligned colloidal nanorods
(Royal Society of Chemistry, 2015) Gao, Y.; Ta, V. D.; Zhao, X.; Wang Y.; Chen R.; Mutlugün, E.; Fong, K. E.; Tan S.T.; Dang C.; Sun, X. W.; Sun, H.; Demir, Hilmi Volkan
In recent years, colloidal semiconductor nanorods have attracted great interest for polarized spontaneous emission. However, their polarized gain has not been possible to achieve so far. In this work we show the highly polarized stimulated emission from the densely packed ensembles of core-seeded nanorods in a cylindrical cavity. Here CdSe/CdS dot-in-rods were coated and aligned on the inner wall of a capillary tube, providing optical feedback for the nanorod gain medium. Results show that the polarized gain originates intrinsically from the aligned nanorods and not from the cavity and that the optical anisotropy of the nanorod ensemble was amplified with the capillary tube, resulting in highly polarized whispering gallery mode lasing. The highly polarized emission and lasing, together with easy fabrication and flexible incorporation, make this microlaser a promising candidate for important color conversion and enrichment applications including liquid crystal display backlighting and laser lighting. This journal is © The Royal Society of Chemistry.
Open Access
Robust whispering-gallery-mode microbubble lasers from colloidal quantum dots
(American Chemical Society, 2017) Wang Y.; Ta, V. D.; Leck K.S.; Tan, B. H. I.; Wang, Z.; He T.; Ohl, C.-D.; Demir, Hilmi Volkan; Sun, H.
Microlasers hold great promise for the development of photonics and optoelectronics. Among the discovered optical gain materials, colloidal quantum dots (CQDs) have been recognized as the most appealing candidate due to the facile emission tunability and solution processability. However, to date, it is still challenging to develop CQD-based microlasers with low cost yet high performance. Moreover, the poor long-term stability of CQDs remains to be the most critical issue, which may block their laser aspirations. Herein, we developed a unique but generic approach to forming a novel type of a whispering-gallery-mode (WGM) microbubble laser from the hybrid CQD/poly(methyl methacrylate) (PMMA) nanocomposites. The formation mechanism of the microbubbles was unraveled by recording the drying process of the nanocomposite droplets. Interestingly, these microbubbles naturally serve as the high-quality WGM laser resonators. By simply changing the CQDs, the lasing emission can be tuned across the whole visible spectral range. Importantly, these microbubble lasers exhibit unprecedented long-term stability (over one year), sufficient for practical applications. As a proof-of-concept, the potential of water vapor sensing was demonstrated. Our results represent a significant advance in microlasers based on the advantageous CQDs and may offer new possibilities for photonics and optoelectronics.
Open Access
Smolign: a spatial motifs-based protein multiple structural alignment method
(Institute of Electrical and Electronics Engineers, 2012) Sun, H.; Sacan, A.; Ferhatosmanoglu, H.; Wang Y.
Availability of an effective tool for protein multiple structural alignment (MSTA) is essential for discovery and analysis of biologically significant structural motifs that can help solve functional annotation and drug design problems. Existing MSTA methods collect residue correspondences mostly through pairwise comparison of consecutive fragments, which can lead to suboptimal alignments, especially when the similarity among the proteins is low. We introduce a novel strategy based on: building a contactwindow based motif library from the protein structural data, discovery and extension of common alignment seeds from this library, and optimal superimposition of multiple structures according to these alignment seeds by an enhanced partial order curve comparison method. The ability of our strategy to detect multiple correspondences simultaneously, to catch alignments globally, and to support flexible alignments, endorse a sensitive and robust automated algorithm that can expose similarities among protein structures even under low similarity conditions. Our method yields better alignment results compared to other popular MSTA methods, on several protein structure data sets that span various structural folds and represent different protein similarity levels. A web-based alignment tool, a downloadable executable, and detailed alignment results for the data sets used here are available at http://sacan.biomed. drexel.edu/Smolign and http://bio.cse.ohio-state.edu/Smolign.
Open Access
Snippet based trajectory statistics histograms for assistive technologies
(Springer, 2014-09) İscen, Ahmet; Wang Y.; Duygulu, Pınar; Hauptmann, A.
Due to increasing hospital costs and traveling time, more and more patients decide to use medical devices at home without traveling to the hospital. However, these devices are not always very straight-forward for usage, and the recent reports show that there are many injuries and even deaths caused by the wrong use of these devices. Since human supervision during every usage is impractical, there is a need for computer vision systems that would recognize actions and detect if the patient has done something wrong. In this paper, we propose to use Snippet Based Trajectory Statistics Histograms descriptor to recognize actions in two medical device usage problems; inhaler device usage and infusion pump usage. Snippet Based Trajectory Statistics Histograms encodes the motion and position statistics of densely extracted trajectories from a video. Our experiments show that by using Snippet Based Trajectory Statistics Histograms technique, we improve the overall performance for both tasks. Additionally, this method does not require heavy computation, and is suitable for real-time systems. © Springer International Publishing Switzerland 2015.
Open Access
A statistical framework for mapping risk genes from de novo mutations in whole-genome-sequencing studies
(Cell Press, 2018) Liu, Y.; Liang, Y.; Çiçek, A. Ercüment; Li, Z.; Li, J.; Muhle, R. A.; Krenzer, M.; Mei, Y.; Wang Y.; Knoblauch, N.; Morrison, J.; Zhao, S.; Jiang, Y.; Geller, E.; Ionita-Laza, I.; Wu, J.; Xia, K.; Noonan, J. P.; Sun, Z. S.; He, X.
Analysis of de novo mutations (DNMs) from sequencing data of nuclear families has identified risk genes for many complex diseases, including multiple neurodevelopmental and psychiatric disorders. Most of these efforts have focused on mutations in protein-coding sequences. Evidence from genome-wide association studies (GWASs) strongly suggests that variants important to human diseases often lie in non-coding regions. Extending DNM-based approaches to non-coding sequences is challenging, however, because the functional significance of non-coding mutations is difficult to predict. We propose a statistical framework for analyzing DNMs from whole-genome sequencing (WGS) data. This method, TADA-Annotations (TADA-A), is a major advance of the TADA method we developed earlier for DNM analysis in coding regions. TADA-A is able to incorporate many functional annotations such as conservation and enhancer marks, to learn from data which annotations are informative of pathogenic mutations, and to combine both coding and non-coding mutations at the gene level to detect risk genes. It also supports meta-analysis of multiple DNM studies, while adjusting for study-specific technical effects. We applied TADA-A to WGS data of ∼300 autism-affected family trios across five studies and discovered several autism risk genes. The software is freely available for all research uses.
Open Access
Stimulated emission and lasing from CdSe/CdS/ZnS core-multi-shell quantum dots by simultaneous three-photon absorption
(Wiley - V C H Verlag GmbH, 2014) Wang Y.; Ta, V. D.; Gao, Y.; He, T. C.; Chen R.; Mutlugun, E.; Demir, Hilmi Volkan; Sun, H. D.
Three-photon pumped stimulated emission and coherent random lasing from colloidal CdSe/CdS/ZnS core-multishell quantum dots are achieved for the first time. These results can offer new possibilities in biology and photonics, as well as at their intersection of biophotonics.
Open Access
Unraveling the ultralow threshold stimulated emission from CdZnS/ZnS quantum dot and enabling high ‐ Q microlasers
(Wiley-VCH Verlag, 2015) Wang Y.; Fong, K. E.; Yang, S.; Ta, V.; Gao, Y.; Wang, Z.; Nalla, V.; Demir, Hilmi Volkan; Sun, H.
The newly engineered ternary CdZnS/ZnS colloidal quantum dots (CQDs) are found to exhibit remarkably high photoluminescence quantum yield and excellent optical gain properties. However, the underlying mechanisms, which could offer the guidelines for devising CQDs for optimized photonic devices, remain undisclosed. In this work, through comprehensive steady-state and time-resolved spectroscopy studies on a series of CdZnS-based CQDs, we unambiguously clarify that CdZnS-based CQDs are inherently superior optical gain media in the blue spectral range due to the slow Auger process and that the ultralow threshold stimulated emission is enabled by surface/interface engineering. Furthermore, external cavity-free high-Q quasitoroid microlasers were produced from self-assembly of CdZnS/ZnS CQDs by facile inkjet printing technique. Detailed spectroscopy analysis confirms the whispering gallery mode lasing mechanism of the quasitoroid microlasers. This tempting microlaser fabrication method should be applicable to other solution-processed gain materials, which could trigger broad research interests. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA.
Open Access
Unusual fluorescent properties of stilbene units and cdzns/zns quantum dots nanocomposites: white-light emission in solution versus light-harvesting in films
(Wiley - V C H Verlag GmbH & Co. KGaA, 2016) He T.; Gao, Y.; Gao, y.; Lin, X.; Chen R.; Hu, W.; Zhao, X.; Wang Y.; Demir, Hilmi Volkan; Fan, Q.; Grimsdale, A. C.; Sun, H.
Nanocomposites with organic–inorganic properties represent a new fi eld of basic research and offer prospects for many novel applications in extremely diverse fi elds, due to their remarkable emerging new properties and multifunctional nature. However, controllable manipulation of their fl uorescent properties in different phases is still challenging, which seriously limits the related applications of nanocomposites. In this work, a convenient protocol to fabricate organic–inorganic nanocomposites composed of stilbene chromophores and CdZnS/ZnS quantum dots (QDs) pairs, with controllable fl uorescent properties is presented. It is found that stable white-light emission can be achieved only in solution phase, with negligible energy transfer or reabsorption between chromophores and QDs pairs. By contrast, when the nanocomposites are deposited as blended fi lms, they cannot give rise to white-light emission, no matter what donor/acceptor volume ratios are used. However, the blended fi lms can exhibit near-unity effi ciency (94%) of Förster resonance energy transfer from QDs to chromophores. The underlying physical mechanisms are revealed through comprehensive steady-state and time-resolved spectroscopic analysis. This work suggests that the CdZnS/ZnS QDs/stilbene nanocomposites can be directly used for fl uorescence sensors and probes in biological system as well as fundamental investigation of lightharvesting, and also sheds light on developing other new materials for artifi cial photosynthesis and optoelectronics.