Defect-Induced Photoluminescence Enhancement and Corresponding Transport Degradation in Individual Suspended Carbon Nanotubes
- Univ. of Southern California, Los Angeles, CA (United States). Dept. of Physics and Astronomy
- Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry
- Univ. of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering
- Korea Polytechnic Univ., Siheung, Gyeonggi (Korea, Republic of)
- Univ. of Southern California, Los Angeles, CA (United States). Dept. of Physics and Astronomy; Univ. of Southern California, Los Angeles, CA (United States). Dept. of Electrical Engineering
The utilization of defects in carbon nanotubes to improve their photoluminescence efficiency has become a widespread study towards the realization of efficient light emitting devices. Here, we report a detailed comparison of defects in nanotubes (quantified by Raman spectroscopy) and photoluminescence (PL) intensity of individual suspended carbon nanotubes (CNTs). We have also the evaluated the impact of these defects on the electron/hole transport in the nanotubes, which is crucial for the ultimate realization of optoelectronic devices. We find that brightly luminescent nanotubes exhibit a pronounced D-band in their Raman spectra, and vice versa, dimly luminescent nanotubes exhibit almost no D-band. Here, defects are advantageous for light emission by trapping excitons, which extends their lifetimes. We quantify this behavior by plotting the PL intensity as a function of the ID/IG band Raman intensity ratio, which exhibits a Lorentz distribution peaked at ID/IG=0.17. For CNTs with a ID/IG ratio >0.25, the PL intensity decreases, indicating that, above some critical density, non-radiative recombination at defect sites dominates over the advantages of exciton trapping. In an attempt to fabricate optoelectronic devices based on these brightly luminescent CNTs, we transferred these suspended CNTs to platinum electrodes and found that the brightly photoluminescent nanotubes exhibit nearly infinite resistance due to these defects while those without bright photoluminescence exhibit finite resistance. These findings indicate a potential limitation in the use of brightly luminescent CNTs for optoelectronic applications.
- Research Organization:
- Univ. of Southern California, Los Angeles, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- FG02-07ER46376
- OSTI ID:
- 1540709
- Alternate ID(s):
- OSTI ID: 1437328
- Journal Information:
- Physical Review Applied, Vol. 9, Issue 5; ISSN 2331-7019
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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