The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Russell J Holmes - One of the best experts on this subject based on the ideXlab platform.
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Tailored exciton diffusion in organic photovoltaic cells for enhanced power conversion efficiency
Nature Materials, 2012Co-Authors: S M Menke, Wade A Luhman, Russell J HolmesAbstract:Photoconversion in planar-Heterojunction organic photovoltaic cells (OPVs) is limited by a short exciton diffusion length (LD) that restricts migration to the dissociating electron donor/acceptor interface. Consequently, bulk Heterojunctions are often used to realize ...
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Organic Photovoltaic Cells Based on Continuously Graded Donor–Acceptor Heterojunctions
Selected Topics in Quantum Electronics, IEEE Journal of, 2010Co-Authors: Richa Pandey, Russell J HolmesAbstract:We demonstrate enhanced organic photovoltaic cell (OPV) efficiency through the use of continuously graded donor-acceptor (D-A) Heterojunctions. Device performance is a strong function of both D-A grading and overall composition ratio. The use of a tunable gradient permits an increase in the D-A interface area for high-exciton diffusion efficiency relative to a planar Heterojunction, while also improving the charge collection efficiency relative to a uniform mixture. Using the archetypical D-A pair of copper phthalocyanine and C60, a power conversion efficiency of ηP = (2.1 ± 0.1)% is realized under 100 mW/cm2 simulated AM1.5G solar illumination for a graded Heterojunction. This represents an improvement in ηP of ~60% relative to a planar Heterojunction OPV and ~20% compared to a uniformly mixed Heterojunction OPV.
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Graded donor-acceptor Heterojunctions for efficient organic photovoltaic cells.
Advanced materials (Deerfield Beach, Fla.), 2010Co-Authors: Richa Pandey, Russell J HolmesAbstract:Graded donor-acceptor Heterojunctions for efficient organic photovoltaic cells are fabricated using boron subphthalocyanine chloride (SubPc) and C(60). The graded Heterojunction significantly increases the exciton diffusion efficiency relative to a planar architecture, and improves the charge collection efficiency relative to a uniformly mixed architecture. A power conversion efficiency of (4.2 +/- 0.1)% is realized in a graded Heterojunction OPV at 100 mW cm(-2) AM1.5G illumination intensity.
James C. Sturm - One of the best experts on this subject based on the ideXlab platform.
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hole blocking titanium oxide silicon Heterojunction and its application to photovoltaics
Applied Physics Letters, 2013Co-Authors: Sushobhan Avasthi, William E. Mcclain, Gabriel Man, Antoine Kahn, Jeffrey Schwartz, James C. SturmAbstract:In contrast to the numerous reports on narrow-bandgap Heterojunctions on silicon, such as strained Si1−xGex on silicon, there have been very few accounts of wide-bandgap semiconducting Heterojunctions on silicon. Here, we present a wide-bandgap Heterojunction—between titanium oxide and crystalline silicon—where the titanium oxide is deposited via a metal-organic chemical vapor deposition process at substrate temperatures of only 80–100 °C. The deposited films are conformal and smooth at the nanometer scale. Electrically, the TiO2/Si Heterojunction prevents transport of holes while allowing transport of electrons. This selective carrier blocking is used to demonstrate a low-temperature processed silicon solar cell.
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Hole-blocking titanium-oxide/silicon Heterojunction and its application to photovoltaics
Applied Physics Letters, 2013Co-Authors: Sushobhan Avasthi, William E. Mcclain, Gabriel Man, Antoine Kahn, Jeffrey Schwartz, James C. SturmAbstract:In contrast to the numerous reports on narrow-bandgap Heterojunctions on silicon, such as strained Si1−x Ge x on silicon, there have been very few accounts of wide-bandgap semiconducting Heterojunctions on silicon. Here, we present a wide-bandgap Heterojunction—between titanium oxide and crystalline silicon—where the titanium oxide is deposited via a metal-organic chemical vapor deposition process at substrate temperatures of only 80–100 °C. The deposited films are conformal and smooth at the nanometer scale. Electrically, the TiO2/Si Heterojunction prevents transport of holes while allowing transport of electrons. This selective carrier blocking is used to demonstrate a low-temperature processed silicon solar cell.
Carlo A. Pignedoli - One of the best experts on this subject based on the ideXlab platform.
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intraribbon Heterojunction formation in ultranarrow graphene nanoribbons
ACS Nano, 2012Co-Authors: Stephan Blankenburg, Rached Jaafar, Roman Fasel, Pascal Ruffieux, Daniele Passerone, Xinliang Feng, Klaus Mullen, Carlo A. PignedoliAbstract:Graphene nanoribbons—semiconducting quasi-one-dimensional graphene structures—have great potential for the realization of novel electronic devices. Recently, graphene nanoribbon Heterojunctions—interfaces between nanoribbons with unequal band gaps—have been realized with lithographic etching techniques and via chemical routes to exploit quantum transport phenomena. However, standard fabrication techniques are not suitable for ribbons narrower than ∼5 nm and do not allow to control the width and edge structure of a specific device with atomic precision. Here, we report the realization of graphene nanoribbon Heterojunctions with lateral dimensions below 2 nm via controllable dehydrogenation of polyanthrylene oligomers self-assembled on a Au(111) surface from molecular precursors. Atomistic simulations reveal the microscopic mechanisms responsible for intraribbon Heterojunction formation. We demonstrate the capability to selectively modify the Heterojunctions by activating the dehydrogenation reaction on sin...
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Intraribbon Heterojunction formation in ultranarrow graphene nanoribbons
ACS Nano, 2012Co-Authors: Stephan Blankenburg, Rached Jaafar, Roman Fasel, Jinming Cai, Pascal Ruffieux, Daniele Passerone, Xinliang Feng, Klaus Mullen, Carlo A. PignedoliAbstract:Graphene nanoribbons-semiconducting quasi-one-dimensional graphene structures-have great potential for the realization of novel electronic devices. Recently, graphene nanoribbon Heterojunctions-interfaces between nanoribbons with unequal band gaps-have been realized with lithographic etching techniques and via chemical routes to exploit quantum transport phenomena. However, standard fabrication techniques are not suitable for ribbons narrower than ~5 nm and do not allow to control the width and edge structure of a specific device with atomic precision. Here, we report the realization of graphene nanoribbon Heterojunctions with lateral dimensions below 2 nm via controllable dehydrogenation of polyanthrylene oligomers self-assembled on a Au(111) surface from molecular precursors. Atomistic simulations reveal the microscopic mechanisms responsible for intraribbon Heterojunction formation. We demonstrate the capability to selectively modify the Heterojunctions by activating the dehydrogenation reaction on single units of the nanoribbons by electron injection from the tip of a scanning tunneling microscope.
Peter Chen - One of the best experts on this subject based on the ideXlab platform.
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ch3nh3pbi3 perovskite fullerene planar Heterojunction hybrid solar cells
Advanced Materials, 2013Co-Authors: Jun Yuan Jeng, Yi Fang Chiang, Shin Rung Peng, Peter ChenAbstract:All-solid-state donor/acceptor planar-Heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such Heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.
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CH3NH3PbI3 perovskite/fullerene planar-Heterojunction hybrid solar cells
Advanced Materials, 2013Co-Authors: Jun Yuan Jeng, Yi Fang Chiang, Mu Huan Lee, Shin Rung Peng, Tzung Fang Guo, Peter Chen, Ten-chin WenAbstract:All-solid-state donor/acceptor planar-Heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such Heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.
Jun Yuan Jeng - One of the best experts on this subject based on the ideXlab platform.
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ch3nh3pbi3 perovskite fullerene planar Heterojunction hybrid solar cells
Advanced Materials, 2013Co-Authors: Jun Yuan Jeng, Yi Fang Chiang, Shin Rung Peng, Peter ChenAbstract:All-solid-state donor/acceptor planar-Heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such Heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.
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CH3NH3PbI3 perovskite/fullerene planar-Heterojunction hybrid solar cells
Advanced Materials, 2013Co-Authors: Jun Yuan Jeng, Yi Fang Chiang, Mu Huan Lee, Shin Rung Peng, Tzung Fang Guo, Peter Chen, Ten-chin WenAbstract:All-solid-state donor/acceptor planar-Heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such Heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.
