Sensitizer–host–annihilator ternary-cascaded triplet energy landscape for efficient photon upconversion in the solid state

In this paper, we introduce a new strategy for improving the efficiency of upconversion emissions based on triplet–triplet exciton annihilation (TTA-UC) in the solid state. We designed a ternary blend system consisting of a triplet sensitizer (TS), an exciton-transporting host polymer, and a small amount of an annihilator in which the triplet-state energies of the TS, host, and annihilator decrease in this order. The key idea underpinning this concept involves first transferring the triplet excitons generated by the TS to the host and then to the annihilator, driven by the cascaded triplet energy landscape. Because of the small annihilator blend ratio, the local density of triplet excitons in the annihilator domain is higher than those in conventional binary TS/annihilator systems, which is advantageous for TTA-UC because TTA is a density-dependent bimolecular reaction. We tracked the triplet exciton dynamics in the ternary blend film by transient absorption spectroscopy. Host triplet excitons are generated through triplet energy transfer from the TS following intersystem crossing in the TS. These triplet excitons then diffuse in the host domain and accumulate in the annihilator domain. The accumulated triplet excitons undergo TTA to generate singlet excitons that are higher in energy than the excitation source, resulting in UC emission. Based on the excitation-intensity and blend-ratio dependences of TTA-UC, we found that our concept has a positive impact on accelerating TTA

Socioeconomic topography : inner city economic development and Geographic Information Systems

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1999.Includes bibliographical references (leaves 95-96).Targeting project areas and defining the objectives are the most important procedures to plan neighborhood economic development, such as the Boston Main Street Program. Which shopping district is to be encouraged and how? However, this has not been an easy task, especially when the neighborhood is in the inner city, because the inner city is so diversified that planners can not find clear spatial patterns on which to base their decisions. This paper attempts to extract patterns of socioeconomic phenomena relevant to economic development and map them. The advancing technology of Geographic Information Systems (GIS) has made it easier to apply raster (grid cell or bit pattern) analysis to studying urban spatial patterns. A map that shows socioeconomic phenomena via rasterization and smoothing processing is called "socioeconomic topography" here. Just as conventional topography shows us geographical features, socioeconomic topography illustrates the spatial pattern and clustering of socioeconomic features of a given area. The following maps are created as socioeconomic topography to support planning of inner city economic development: (1) land use allocation, (2) land value, (3) business variation, (4) shopping convenience, and (5) leading industrial clusters. On each map, spatial patterns stand out clearly from the chaos of Boston's inner city. Socioeconomic topography offers a new way of understanding the inner city and illuminates the need of made-to-order projects for each shopping district.by Hideo Sakamoto.M.C.P

A new crystal plasticity constitutive equation based on crystallographic misorientation theory

Since plastic deformation of polycrystal sheet metal is greatly affected by its initial and plastic deformed textures, multi-scale finite element (FE) analysis based on homogenization with considering micro-polycrystal morphology is required [1]. We formulated a new crystal plasticity constitutive equation to introduce not only the effect of crystal orientation distribution, but also the size of crystal grain and/or the effect of crystal grain boundary for the micro-FE analysis. The hardening evolution equation based on strain gradient theory [2], [3] was modified to introduce curvature of crystal orientation based on crystallographic misorientation theory. We employed two-scale structure, such as a microscopic polycrystal structure and a macroscopic elastic/plastic continuum. Our analysis code predicts the plastic deformation of polycrystal metal in the macro-scale, and simultaneously the crystal texture and misorientation evolutions in the micro-scale. In this study, we try to reveal the relationship between the plastic deformation and the microscopic crystal misorientation evolution by using the homogenized FE procedure with the proposed crystal plasticity constitutive equation. The crystallographic misorientation evolution, which affects on the plastic deformation of FCC polycrystal metal, was investigated by using the multi-scale FE analysis. We confirmed the availability of our analysis code employing the new constitutive equation through the comparison of a uniaxial tensile problem with the numerical result and the experimental one

Triplet sensitization via charge recombination at organic heterojunction for efficient near-infrared to visible solid-state photon upconversion

Realizing efficient near-infrared to visible photon upconversion in the solid state is pivotal for commercial applications in various fields. We previously reported a solid-state upconversion device which imitated the photovoltaic conversion mechanisms of organic solar cells. This leads to a significant improvement of up to 2.3% in the external quantum efficiency, which is two orders of magnitude higher than that of conventional devices. Here, we investigate the upconversion mechanism of this device. We examine exciton and charge dynamics using transient absorption spectroscopy and find that approximately 67% of incident photons are utilized owing to fast singlet exciton diffusion in the nonfullerene acceptor layer. Strikingly, triplet excitons are accumulated near the donor/acceptor interface, enabling accelerated triplet–triplet annihilation by a factor of more than 10

A STUDY ON FUNCTION OF PROFESSIONAL COORDINATOR FOR REVITALIZATION OF COMMUNITY USING THE METHOD OF PROFILES OF PRACTITIONERS

協働のまちづくりの実践においては，多様なステークホルダーの利害を調整する調整役による調整機能が重要な鍵となっている．しかし，その実態は見えにくく，知見として整理されていない．本研究は，「実践のプロファイリング手法」を用い，立場や専門の異なる5名のプロファイルから，調整役機能を明らかにすることを目的としている．既存研究から調整役機能としての要素を抽出，整理し，立場も異なる5名のプロジェクト実践者のプロファイルから抽出した行動をあてはめ，整理することで，立場を超えた共通の調整役機能や立場による相違を分析した．その結果，すべての対象者が共通の活動目的に対し行動を起こしていたが，その行動の手法が異なることがわかった．すなわち，調整役機能にとって基礎的な要求事項が明らかになったと言える．The collaboration between residents, local government and professionals is said to be an important issue for revitalization of community. Although, it is inevitable for the projects of revitalization of community to adopt a collaborative approach with getting local government and coordination experts' support, confusions in partnership sometimes occur due to the lack of continuous or effective professional coordination. The aim of this study is to clarify rolls of professional coordinator in forming collaborative activity using a method of profile of practitioners proposed by John Forester, by analyzing profiles of five practitioners whose position of collaboration or professional expertise are different. As a result, All practitioners had the some actions for the objectives of collaborative approach listed by the authors, but there action for each is not the same style and depends on their role