Thursday, June 17, 2010

Energetically-Conjoined Annihilation Upconversion in Multi-component Organic Systems

Energetically-Conjoined Annihilation Upconversion in Multi-component Organic Systems

Date: June 28, 2010

Time: 12 Noon - 1 p.m.

Room: CREOL Conference Room 102

A Nanoscience Technology, Advanced materials processing and analysis center, and the College of Optics and Photonics Seminar

Dr. Stanislav Baluschev1, 2

Institute for Polymer Research

2 Optics and Spectroscopy Department

Sofia University

Abstract:

The processes of photon energy upconversion (UC), where locally (or in

situ) photons

strongly blue shifted regarding the excitation wavelength have been intensively studied.

Different UC-techniques, including Two-Photon Absorption (TPA), Energy Transfer Upconversion (ETU) have been used. As optical excitation near infrared

(NIR) or infra red (IR) light sources are used.

In contrast to the all previously described UC-techniques the fundamental advantage of the energetically conjoined triplet-triplet annihilation up-conversion (TTA -UC) is its inherent independence on the coherence of the excitation light. Another principal advantage of TTA - UC process is the very low required intensity (as low as 20 mWcm-2) and extremely low spectral power density (as low as 125╬╝Wnm-1) of the excitation source needed - so it can in reality be the Sun.

We present the summarised results of our investigations and experiments and state the general requirements for the materials’ parameters of the couple sensitizer/emitter in order to obtain efficient energetically conjoined TTA−UC. We also present our working UC-devices for spectrum concentration via UC with up-converted fluorescence quantum yield of 3.2% realized at ultra-low excitation intensities (~ 20 mWcm-2).

For More Information:

USHABEN LAL

NanoScience Technology Center

Ph: 407 882 0032

Email: ulal@mail.ucf.edu.

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