Aggregation-induced optical responses are ubiquitous among a wide range of organic and inorganic compounds. Here, we demonstrate an unprecedented effect of aggregation on the photoluminescence (PL) profiles of [core + exo]-type [Au] clusters, which displayed a change in the dominant PL emission mode from fluorescence to phosphorescence-type upon aggregation. In solvents in which cluster molecules are highly soluble and exist as monomers, they displayed single PL bands at ∼600 nm at ambient temperatures. However, in solvents in which cluster molecules are less soluble and cluster aggregation is induced, a new PL band at ∼700 nm also emerged. Lifetime measurements revealed that the PL emissions at ∼600 and ∼700 nm had fluorescence and phosphorescence characters, respectively. Studies of the excitation spectra suggested that organized cluster assemblies were responsible for the lower-energy emission at ∼700 nm and had exceptionally high emission activity. Accordingly, intense phosphorescence-type emissions were observed in the solid state in which the quantum efficiencies were higher by two orders of magnitude than those of the corresponding monomeric forms in solution. This work provides an example of the critical effects of cluster aggregation events on their optical properties and shows the potential of such effects in the design of cluster-based materials with unique functions and properties.
Objectives: This study aimed to qualitatively analyze the experiences and perceptions of students at a nursing college in Japan who studied abroad in Asia and North America, thereby identifying the full range of benefits of study abroad programs for Japanese nursing students. Methods: We conducted a qualitative analysis of the reflection papers and free-response questionnaire items completed by 50 Japanese undergraduate nursing students who participated in 9 study abroad programs in Asia and North America. Content analysis of the data proceeded from typological and deductive to data-driven and inductive, recursively and collaboratively. Results: The results reveal perceived benefits in the areas of English language proficiency and motivation; knowledge of nursing practices, healthcare systems, and global health; cultural awareness and sensitivity; and various types of identity development (second-language motivation and identity, national/ethnic identity, professional identity, identity as a global citizen, and personal growth). It was also shown that students' perceptions of what they learned or gained varied according to the specific characteristics of each study abroad program. Conclusions: Study abroad experiences are often critical turning points that enhance nursing students' identity formation in the context of multiple and overlapping communities of practice. They also enhance core elements of the educational mission of a nursing college, particularly relating to liberal arts and internationalization. These findings can inform the development of assessment tools to be used in conjunction with study abroad programs at nursing colleges.
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