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Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
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Near-Infrared Lasing from Small-Molecule Organic Hemispheres
Xuedong Wang1,2, Qing Liao3, Hui Li1,2
1†Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
Journal of the American Chemical Society
|July 8, 2015
Summary
Researchers developed a novel organic molecule, DPHP, that self-assembles into micro-hemispheres for efficient near-infrared (NIR) organic lasers. This breakthrough overcomes limitations of traditional semiconductor lasers, enabling low-cost, solution-processed NIR light sources.
Area of Science:
- Organic electronics
- Photonics
- Materials science
Background:
- Near-infrared (NIR) lasers are crucial for telecommunications, imaging, and spectroscopy.
- Current inorganic NIR lasers (e.g., GaAs) are expensive and complex to fabricate.
- Organic semiconductors offer tunable properties and solution processability but face challenges like low stimulated emission and exciton-exciton annihilation.
Purpose of the Study:
- To design and synthesize a novel organic molecule for efficient NIR lasing.
- To overcome major hurdles in organic NIR laser development, including fast nonradiative decay and exciton-exciton annihilation.
- To create a self-assembled microcavity for enhanced NIR emission.
Main Methods:
- Synthesis of a novel amphiphilic small organic molecule, (E)-3-(4-(di-p-tolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP).
- Characterization of DPHP's self-assembly into micrometer-sized hemispheres.
- Evaluation of photoluminescence quantum efficiency, radiative rate enhancement, and microcavity properties (high-Q whispering gallery mode).
- Demonstration of NIR lasing in a single DPHP hemisphere at room temperature.
Main Results:
- DPHP self-assembles into NIR-emitting hemispheres acting as high-Q (∼1.4 × 10^3) whispering gallery mode microcavities.
- Achieved a photoluminescence quantum efficiency of ∼15.2% and enhanced radiative rate (∼1.98 × 10^9 s^-1) due to exciton-vibrational coupling and J-type molecular coupling.
- Eliminated exciton-exciton annihilation, a key loss channel in organic lasers.
- Demonstrated room-temperature NIR lasing with a low threshold (∼610 nJ/cm^2) in a single DPHP hemisphere.
Conclusions:
- The developed DPHP molecule and its self-assembled hemispheres represent a significant advancement for organic NIR lasers.
- This work paves the way for low-cost, solution-processed organic coherent light sources.
- The findings facilitate the integration of organic NIR lasers into compact optoelectronic devices.
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