@article {70, title = {Controlled doping of carbon nanotubes with metallocenes for application in hybrid carbon nanotube/Si solar cells}, journal = {Nano LettNano Lett}, volume = {14}, number = {6}, year = {2014}, note = {Li, Xiaokai
Guard, Louise M
Jiang, Jie
Sakimoto, Kelsey
Huang, Jing-Shun
Wu, Jianguo
Li, Jinyang
Yu, Lianqing
Pokhrel, Ravi
Brudvig, Gary W
Ismail-Beigi, Sohrab
Hazari, Nilay
Taylor, Andre D
eng
Research Support, Non-U.S. Gov{\textquoteright}t
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2014/05/02 06:00
Nano Lett. 2014 Jun 11;14(6):3388-94. doi: 10.1021/nl500894h. Epub 2014 May 13.}, month = {Jun 11}, pages = {3388-94}, abstract = {

There is considerable interest in the controlled p-type and n-type doping of carbon nanotubes (CNT) for use in a range of important electronics applications, including the development of hybrid CNT/silicon (Si) photovoltaic devices. Here, we demonstrate that easy to handle metallocenes and related complexes can be used to both p-type and n-type dope single-walled carbon nanotube (SWNT) thin films, using a simple spin coating process. We report n-SWNT/p-Si photovoltaic devices that are \>450 times more efficient than the best solar cells of this type currently reported and show that the performance of both our n-SWNT/p-Si and p-SWNT/n-Si devices is related to the doping level of the SWNT. Furthermore, we establish that the electronic structure of the metallocene or related molecule can be correlated to the doping level of the SWNT, which may provide the foundation for controlled doping of SWNT thin films in the future.

}, isbn = {1530-6992 (Electronic)
1530-6984 (Linking)}, doi = { 10.1021/nl500894h}, author = {Li, X. and Guard, L. M. and Jiang, J. and Sakimoto, K. and Huang, J. S. and Wu, J. and Li, J. and Yu, L. and Pokhrel, R. and Brudvig, G. W. and Ismail-Beigi, S. and Hazari, N. and Taylor, A. D.} } @article {71, title = {Role of HF in oxygen removal from carbon nanotubes: implications for high performance carbon electronics}, journal = {Nano LettNano Lett}, volume = {14}, number = {11}, year = {2014}, note = {Li, Xiaokai
Huang, Jing-Shun
Nejati, Siamak
McMillon, Lyndsey
Huang, Su
Osuji, Chinedum O
Hazari, Nilay
Taylor, Andre D
eng
Research Support, Non-U.S. Gov{\textquoteright}t
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2014/10/07 06:00
Nano Lett. 2014 Nov 12;14(11):6179-84. doi: 10.1021/nl502401c. Epub 2014 Oct 29.}, month = {Nov 12}, pages = {6179-84}, abstract = {

Oxygen removal from SWNTs is crucial for many carbon electronic devices. This work shows that HF treatment followed by current stimulation is a very effective method for oxygen removal. Using a procedure involving HF treatment, current stimulation and spin-casting AgNWs onto a SWNT thin film, record high efficiency SWNT/p-Si solar cells have been developed.

}, keywords = {carbon electronics, carbon nanotubes, Hydrofluoric acid, photovoltaic devices, silver nanowires}, isbn = {1530-6992 (Electronic)
1530-6984 (Linking)}, doi = { 10.1021/nl502401c}, author = {Li, X. and Huang, J. S. and Nejati, S. and McMillon, L. and Huang, S. and Osuji, C. O. and Hazari, N. and Taylor, A. D.} } @article {68, title = {Record high efficiency single-walled carbon nanotube/silicon p-n junction solar cells}, journal = {Nano LettNano Lett}, volume = {13}, number = {1}, year = {2013}, note = {Jung, Yeonwoong
Li, Xiaokai
Rajan, Nitin K
Taylor, Andre D
Reed, Mark A
eng
2012/12/15 06:00
Nano Lett. 2013 Jan 9;13(1):95-9. doi: 10.1021/nl3035652. Epub 2012 Dec 17.}, month = {Jan 9}, pages = {95-9}, abstract = {

Carrier transport characteristics in high-efficiency single-walled carbon nanotubes (SWNTs)/silicon (Si) hybrid solar cells are presented. The solar cells were fabricated by depositing intrinsic p-type SWNT thin-films on n-type Si wafers without involving any high-temperature process for p-n junction formation. The optimized cells showed a device ideality factor close to unity and a record-high power-conversion-efficiency of \>11\%. By investigating the dark forward current density characteristics with varying temperature, we have identified that the temperature-dependent current rectification originates from the thermally activated band-to-band transition of carriers in Si, and the role of the SWNT thin films is to establish a built-in potential for carrier separation/collection. We have also established that the dominant carrier transport mechanism is diffusion, with minimal interface recombination. This is further supported by the observation of a long minority carrier lifetime of ~34 mus, determined by the transient recovery method. This study suggests that these hybrid solar cells operate in the same manner as single crystalline p-n homojunction Si solar cells.

}, isbn = {1530-6992 (Electronic)
1530-6984 (Linking)}, doi = {10.1021/nl3035652}, author = {Jung, Y. and Li, X. and Rajan, N. K. and Taylor, A. D. and Reed, M. A.} } @article {63, title = {Improving the assembly speed, quality, and tunability of thin conductive multilayers}, journal = {ACS NanoACS Nano}, volume = {6}, number = {5}, year = {2012}, note = {Gittleson, Forrest S
Kohn, David J
Li, Xiaokai
Taylor, Andre D
eng
2012/04/21 06:00
ACS Nano. 2012 May 22;6(5):3703-11. doi: 10.1021/nn204384f. Epub 2012 May 7.}, month = {May 22}, pages = {3703-11}, abstract = {While inhomogeneous thin conductive films have been sought after for their flexibility, transparency, and strength, poor control in the processing of these materials has restricted their application. The versatile layer-by-layer assembly technique allows greater control over film deposition, but even this has been hampered by the traditional dip-coating method. Here, we employ a fully automated spin-spray layer-by-layer system (SSLbL) to rapidly produce high-quality, tunable multilayer films. With bilayer deposition cycle times as low as 13 s (~50\% of previously reported) and thorough characterization of film conductance in the near percolation region, we show that SSLbL permits nanolevel control over film growth and efficient formation of a conducting network not available with other methods of multilayer deposition. The multitude of variables from spray time, to spin rate, to active drying available with SSLbL makes films generated by this technique inherently more tunable and expands the opportunity for optimization and application of composite multilayers. A comparison of several polymer-CNT systems deposited by both spin-spray and dip-coating exemplifies the potential of SSLbL assembly to allow for rapid screening of multilayer films. Ultrathin polymer-CNT multilayers assembled by SSLbL were also evaluated as lithium-ion battery electrodes, emphasizing the practical application of this technique.}, isbn = {1936-086X (Electronic)
1936-0851 (Linking)}, author = {Gittleson, F. S. and Kohn, D. J. and Li, X. and Taylor, A. D.} } @article {69, title = {Scalable fabrication of multifunctional freestanding carbon nanotube/polymer composite thin films for energy conversion}, journal = {ACS NanoACS Nano}, volume = {6}, number = {2}, year = {2012}, note = {Li, Xiaokai
Gittleson, Forrest
Carmo, Marcelo
Sekol, Ryan C
Taylor, Andre D
eng
Research Support, Non-U.S. Gov{\textquoteright}t
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2012/01/13 06:00
ACS Nano. 2012 Feb 28;6(2):1347-56. doi: 10.1021/nn2041544. Epub 2012 Jan 24.}, month = {Feb 28}, pages = {1347-56}, abstract = {Translating the unique properties of individual single-walled carbon nanotubes (SWNTs) to the macroscale while simultaneously incorporating additional functionalities into composites has been stymied by inadequate assembly methods. Here we describe a technique for developing multifunctional SWNT/polymer composite thin films that provides a fundamental engineering basis to bridge the gap between their nano- and macroscale properties. Selected polymers are infiltrated into a Mayer rod coated conductive SWNT network to fabricate solar cell transparent conductive electrodes (TCEs), fuel cell membrane electrode assemblies (MEAs), and lithium ion battery electrodes. Our TCEs have an outstanding optoelectronic figure of merit sigma(dc)/sigma(ac) of 19.4 and roughness of 3.8 nm yet are also mechanically robust enough to withstand delamination, a step toward scratch resistance necessary for flexible electronics. Our MEAs show platinum utilization as high as 1550 mW/mg(Pt), demonstrating our technique{\textquoteright}s ability to integrate ionic conductivity of the polymer with electrical conductivity of the SWNTs at the Pt surface. Our battery anodes, which show reversible capacity of approximately 850 mAh/g after 15 cycles, demonstrate the integration of electrode and separator to simplify device architecture and decrease overall weight. Each of these applications demonstrates our technique{\textquoteright}s ability to maintain the conductivity of SWNT networks and their dispersion within a polymer matrix while concurrently optimizing key complementary properties of the composite. Here, we lay the foundation for the assembly of nanotubes and nanostructured components (rods, wires, particles, etc.) into macroscopic multifunctional materials using a low-cost and scalable solution-based processing technique.}, isbn = {1936-086X (Electronic)
1936-0851 (Linking)}, author = {Li, X. and Gittleson, F. and Carmo, M. and Sekol, R. C. and Taylor, A. D.} }