Phosphorescent materials have attracted much attention due to potential applications in solid-state lighting and light emitting diode because they can provide three-fold higher internal quantum efficiency than fluorescent alternatives by harvesting triplet excitons through intersystem crossing. While many organometallic compounds are efficient phosphors due to spin-orbit coupling promoted by metals, they require rare and expensive elements such as platinum and iridium. Developing metal-free phosphorescent materials is promising but challenging because suppressing the vibration of triplets, one of the key processes, is not efficient without heavy metal atoms. While recent studies reveal bright phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. In this presentation, we will report bright room temperature phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (�)-relaxation of isotactic PMMA most efficiently suppresses the vibrational decay and allows the embedded organic phosphors to achieve a bright 7.5% phosphorescence quantum yield. We will also demonstrate a microfluidic device integrated with a novel temperature sensor based on the organic phosphors in the temperature-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temperature sensing ranges by using different polymers. 

Room temperature phosphorescence of metal-free organic materials in amorphous polymer matrices

246th National Meeting (2013)

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