Frequency up-conversion is demonstrated in a polyfluorene-based conjugated polymer. Up-converted emission is observed upon excitation to the red of the 0-0 luminescence band. The emission intensity depends strongly on temperature and provides an accurate probe of the operating temperature of organic light-emitting diodes. Temperature rises of up to 30 K are observed at standard operating current densities of 225 mA/cm2. Due to the low thermal conductivity and heat capacity of the polymer film, the temperature of the film is found to rise slowly on a time-scale of seconds. Upon termination of the current, the temperature decreases again on a time-scale of minutes.
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Research Article| January 14 2002
Frequency up-conversion as a temperature probe of organic opto-electronic devices
John M. Lupton; Frequency up-conversion as a temperature probe of organic opto-electronic devices. Appl. Phys. Lett. 14 January 2002; 80 (2): 186–188. https://doi.org/10.1063/1.1432766
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