APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

23 Feb 2009

Volume 94, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 082501 (2009); http://dx.doi.org/10.1063/1.3085971 (3 pages)

Chunghee Nam, B. G. Ng, F. J. Castaño, M. D. Mascaro, and C. A. Ross
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds
FREE

Single mode microwave irradiation to improve the efficiency of polymer solar cell based on poly(3-hexylthiophene) and fullerene derivative

Osamu Yoshikawa, Taro Sonobe, Takashi Sagawa, and Susumu Yoshikawa

Appl. Phys. Lett. 94, 083301 (2009); http://dx.doi.org/10.1063/1.3077612 (3 pages) | Cited 8 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Single mode microwave irradiation was successfully applied to improve the efficiency of polymer solar cell based on poly (3-hexylthiophene) and [6, 6]-phenyl C61-butyric acid methyl ester for the first time. Treatment at 93 °C for 4 min irradiation was possible to achieve the same effect as the thermal annealing at 150 °C for 6 min, proving this method is superior for morphology control under the mild condition. Energy conversion efficiency of 1.46% for untreated device was improved to 3.30% after microwave irradiation under the condition of AM 1.5, 100 mW/cm2.
Show PACS
84.60.Jt Photoelectric conversion
81.40.Gh Other heat and thermomechanical treatments
FREE

Current-voltage characteristics of poly(3-hexylthiophene) diodes at room temperature

Michele Giulianini, Eric R. Waclawik, John M. Bell, and Nunzio Motta

Appl. Phys. Lett. 94, 083302 (2009); http://dx.doi.org/10.1063/1.3086882 (3 pages) | Cited 10 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the analysis of current-voltage characteristics of regioregular poly(3-hexylthiophene) diodes. Experimental curves were fitted to two models, to take into account at low-moderate electric fields Schottky behavior mixed with space charge limited current (SCLC) regime and, at higher fields, trap-free SCLC. The results provide a description of IV curves over five decades, along with the determination of zero field and effective mobility and the field dependence prefactor. Forward and reverse IV measurements highlighted the presence of shallow and deep localized states inside the band gap. The latter enhance the current over time and have been modeled as an inductorlike element.
Show PACS
85.30.Kk Junction diodes
FREE

Optimized efficiency and angular emission characteristics of white top-emitting organic electroluminescent diodes

Michael Thomschke, Robert Nitsche, Mauro Furno, and Karl Leo

Appl. Phys. Lett. 94, 083303 (2009); http://dx.doi.org/10.1063/1.3088854 (3 pages) | Cited 43 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The concept of an additional capping layer, which is deposited onto the semitransparent top contact, is applied to minimize microcavity effects for white light emission from top-emitting organic light emitting devices (OLEDs). The influence on the optical properties of such devices with silver as top electrode material is discussed using an analytical method and numerical simulations. The results of the theoretical findings are experimentally verified for inverted top emitting devices on opaque substrates, showing broad spectral bandwidth and angle-independent color coordinates.
Show PACS
85.60.Jb Light-emitting devices
FREE

High mobility organic thin film transistors based on monocrystalline rubrene films grown by low pressure hot wall deposition

Yi Chen and Ishiang Shih

Appl. Phys. Lett. 94, 083304 (2009); http://dx.doi.org/10.1063/1.3089572 (3 pages) | Cited 11 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monocrystalline rubrene (5,6,11,12-tetraphenylnaphthacene) films with thickness between 1 and 10 μm and grain sizes as large as 100 μm×2 mm were deposited on thin film transistor substrates at rates ∼ 500 nm/min by a low pressure and hot wall deposition method. Organic thin film transistors with these high quality thin films as active channels have field effect mobility as high as 2.4 cm2/V s and ON/OFF current ratios around 106. The morphology and crystallinity of rubrene films under different deposition conditions were also studied to determine the optimal film deposition conditions.
Show PACS
85.30.Tv Field effect devices
85.75.Hh Spin polarized field effect transistors
FREE

Origin of the ambipolar operation of a pentacene field-effect transistor fabricated on a poly(vinyl alcohol)-coated Ta2O5 gate dielectric with Au source/drain electrodes

Satoko Takebayashi (武林聡子), Shigeomi Abe (阿部重臣), Koichiro Saiki (斉木幸一朗), and Keiji Ueno (上野啓司)

Appl. Phys. Lett. 94, 083305 (2009); http://dx.doi.org/10.1063/1.3089692 (3 pages) | Cited 4 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Pentacene field-effect transistors (FETs) were fabricated on a poly(vinyl alcohol) (PVA)-coated Ta2O5 gate dielectric using Au source/drain electrodes. Their device characteristics were examined before and after annealing the FETs in a vacuum. Before annealing, the pentacene FET showed an ambipolar operation with hole mobility of 0.1 cm2 V−1 s−1 and electron mobility of 0.005 cm2 V−1 s−1. After annealing at 50 °C, however, the p-type operation characteristics almost diminished and an enhanced n-type operation was observed. Na+ ions in the PVA are supposed to change the character of the injection barrier at the Au/pentacene junction and enable the n-type operation.
Show PACS
85.30.Tv Field effect devices
82.45.Fk Electrodes
61.72.Cc Kinetics of defect formation and annealing
72.20.Fr Low-field transport and mobility; piezoresistance
73.40.Ns Metal-nonmetal contacts
FREE

High efficiency electroluminescence devices using a series of Ir(III)-tetrazolate phosphors: Mechanisms for the drive current evolution of quantum yield

Massimo Cocchi, Jan Kalinowski, Stefano Stagni, and Sara Muzzioli

Appl. Phys. Lett. 94, 083306 (2009); http://dx.doi.org/10.1063/1.3081491 (3 pages) | Cited 5 times

Online Publication Date: 25 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate high-brightness and high-efficiency blue-green to yellow-green electrophosphorescent organic light-emitting diodes employing a series of organic Ir complexes [Ir-(C∧N)2(N∧N)]. Three different complexes have been synthesized showing high photoluminescence solid blend efficiencies up to 44%. A low current density increase of the electroluminescence (EL) external quantum efficiency (φEL(ext)) is observed and a maximum of φEL(ext) = 10.6%±0.8% photon/e and power efficiency η = 27±2 lm/W are achieved at a current density of j = 0.01 mA/cm2. We examine various electronic processes that underlie a nonmonotonous current density dependence of the EL quantum efficiency of electrophosphorescent light-emitting diodes. The shape of φEL(ext) versus j is shown to reflect a trade off between electron-hole encounter and charge carrier transit times, electric field effect on electron-hole pair dissociation time, and current driven triplet molecular exciton lifetime.
Show PACS
85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence
71.35.-y Excitons and related phenomena
78.55.Kz Solid organic materials
FREE

Low temperature magnetic field effects in Alq3-based organic light emitting diodes

Y. Zhang, R. Liu, Y. L. Lei, and Z. H. Xiong

Appl. Phys. Lett. 94, 083307 (2009); http://dx.doi.org/10.1063/1.3089844 (3 pages) | Cited 12 times

Online Publication Date: 25 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic field effects on injection current and electroluminescence have been investigated for aluminum tris(8-hydroxyquinoline) (Alq3)-based organic light emitting diodes at the temperature of 12 K. The experimental traces of electroluminescence exhibit a rapid rising at low magnetic field, followed by a decrease at high field strength, whereas the injection current increases continuously. The drive dependence of the high field effect of the quantum efficiency matches that which is expected for the triplet-triplet annihilation process, indicating that the delayed fluorescence from the triplets’ annihilation significantly contributes to the field dependent light emission in our devices.
Show PACS
85.60.Jb Light-emitting devices
78.20.Ls Magneto-optical effects
FREE

Bimolecular recombination in solution-processed 6, 13-bis(pentylphenylethynyl) pentacene thin-film transistor

Chang Hyun Kim, Sung Hoon Kim, Sun Hee Lee, Seung Hoon Han, Min Hee Choi, Tae Woo Jeon, and Jin Jang

Appl. Phys. Lett. 94, 083308 (2009); http://dx.doi.org/10.1063/1.3089574 (3 pages) | Cited 5 times

Online Publication Date: 26 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the light intensity dependence of drain current under illumination for the organic thin-film transistor using 6, 13-bis (pentylphenylethynyl)pentacene, having photosensitivity of up to 107. The carrier concentration in the channel could be achieved by comparing the currents at dark induced by gate potential and those generated under illumination at zero gate voltage. It increases with illumination intensity with a power law of 0.61, suggesting that the bimolecular recombination is the dominant one during the light illumination, resulting in no photocurrent at high gate potential.
Show PACS
85.30.Tv Field effect devices
73.50.Pz Photoconduction and photovoltaic effects
73.61.Ph Polymers; organic compounds
FREE

Contact resistance instability in pentacene thin film transistors induced by ambient gases

S. D. Wang, T. Minari, T. Miyadera, K. Tsukagoshi, and J. X. Tang

Appl. Phys. Lett. 94, 083309 (2009); http://dx.doi.org/10.1063/1.3089246 (3 pages) | Cited 6 times

Online Publication Date: 27 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Top-contact pentacene thin film transistors show the strong susceptibility of the contact resistance to ambient gases. Moisture and oxygen lead to the increase and decrease in the contact resistance, respectively. The phenomenon is interpreted by the local conductivity change in the contact region induced by the adsorption/desorption of ambient gases. The present works suggest that the current injection in the pentacene thin film transistors is strongly correlated with the charge transport property in the contact region, where the contact resistance is mainly controlled by the charge trap states.
Show PACS
85.30.Tv Field effect devices
FREE

Threshold voltage control of bottom-contact n-channel organic thin-film transistors using modified drain/source electrodes

Masatoshi Kitamura, Yasutaka Kuzumoto, Shigeru Aomori, Masakazu Kamura, Jong Ho Na, and Yasuhiko Arakawa

Appl. Phys. Lett. 94, 083310 (2009); http://dx.doi.org/10.1063/1.3090489 (3 pages) | Cited 19 times

Online Publication Date: 27 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Bottom-contact n-channel C60 thin-film transistors (TFTs) with drain/source electrodes modified by benzenethiol derivatives have been fabricated to investigate the influence of the modification on the transistor characteristics. Modification using methylbenzenethiol, aminobenzenethiol, and (dimethylamino)benzenethiol having electron-donating groups causes threshold voltages to shift to low voltages. In addition, the modification provides no significant decrease in saturation mobilities. A C60 TFT with (dimethylamino)benzenethiol-modified electrodes has a low threshold voltage of 5.1 V as compared to that of 16.8 V for a TFT with nonmodified electrodes. The threshold-voltage shift is probably because the modification reduces electron-injection barrier height and improves electron injection into organic semiconductors.
Show PACS
85.30.Tv Field effect devices
85.65.+h Molecular electronic devices
72.20.Fr Low-field transport and mobility; piezoresistance
73.61.Wp Fullerenes and related materials
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close