Photoluminescence, description

Time-resolved PL measurements were also performed using time-correlated single-photon counting (TCSPC) and photoluminescence upconversion (PLUC) spectroscopies. Descriptions of the setups can be found in refs. [14, 65], respectively. All measurements were taken in continuous-flow He cryostats (Oxford Instruments OptistatCF) under inert conditions. Finally, PL efficiency measurements were performed on simple polymer thin films spin coated on Spectrosil substrates using an integrating sphere coupled to an Oriel InstaSpec IV spectrograph and excitation with the same Ar+ laser as above. 

A description is proposed for luminescence decay in Mn-doped CdS quantum dots based on a model implying radiative and dispersive n on-radiative decay of excited impurity ions. The model provides an adequate explanation of experimental photoluminescence kinetics in CdS Mn nanociystals. The excited state lifetime evaluated for Mn ions is about 2.3 ms and close to the bulk case. 

Porous silicon (pSi) at atomic scale is a crystalline material however, it presents a random porous distribution with branches of different morphologies and sizes, as discussed along this book. The description of this disordered porous structure is one of the main theoretical challenges. Due to the fabrication process, pSi presents different surface saturations and internal stmctural strains, both should be adequately simulated. In addition, the inhomogeneity of pSi produces broadening of the photoluminescence response that could be caused by a spread of local bandgaps if there is only a partial interconnection between the nanostructures (Calcott 1977). 

In the last decade, iridium carbonyl complexes have found many applications in homogeneous and heterogeneous catalysis, as well as in photoluminescent and optoelectronic devices. These aspects will be described in the corresponding sections. Here are summarized the main developments in the synthesis, characterization, and some, although brief, descriptions of use of the most remarkable iridium mono-, di-, polycarbonyl and cluster complexes. Specific reactivity of alkyl, aryl iridium carbonyl complexes are dealt with in the appropriate paragraph in this chapter. 

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