APL: Organic Electronics and Photonics http://scitation.aip.org/ APL: Organic Electronics and Photonics Observation of space-charge-limited current due to charge generation at interface of molybdenum dioxide and organic layer http://link.aip.org/link/?APL/95/203306/1&agg=rss Toshinori Matsushima and Hideyuki Murata<br/> Current density-voltage characteristics of hole-only devices are influenced by thicknesses of molybdenum dioxide (MoO) and molybdenum trioxide (MoO) as buffer layers. A space-charge-limited current of N,N-diphenyl-N,N-bis(1-naphthyl)-1,1-biphenyl-4,4-diamine (alpha-NPD) is observed in a wide range o ... [Appl. Phys. Lett. 95, 203306 (2009)] published Fri Nov 20, 2009. Reduced hole injection barrier for achieving ultralow voltage polymer space-charge-limited transistor with a high on/off current ratio http://link.aip.org/link/?APL/95/203305/1&agg=rss Yu-Chiang Chao, Yi-Cheng Lin, Min-Zhi Dai, Hsiao-Wen Zan, and Hsin-Fei Meng<br/> Vertical polymer space-charge limited transistor (SCLT) operated with an ultralow voltage is demonstrated. The influence of aging effect of the oxygen plasma treated indium tin oxide electrode on the hole injection barrier and on the transistor characteristics is investigated. By reducing the hole i ... [Appl. Phys. Lett. 95, 203305 (2009)] published Fri Nov 20, 2009. Fully bendable polymer light emitting devices with carbon nanotubes as cathode and anode http://link.aip.org/link/?APL/95/203304/1&agg=rss Zhibin Yu, Liangbing Hu, Zhitian Liu, Mingliang Sun, Meiliang Wang et al.<br/> Polymer light emitting devices were fabricated by roll lamination using single-walled carbon nanotubes as both anode and cathode. The devices exhibited a low turn-on voltage of 3.8 V, high brightness of 1400 cd/m at 10 V and maximum efficiency of 2.2 cd/A at 480 cd/m. The devices are also highly t ... [Appl. Phys. Lett. 95, 203304 (2009)] published Thu Nov 19, 2009. Electronic properties and open-circuit voltage enhancement in mixed copper phthalocyanine:fullerene bulk heterojunction photovoltaic devices http://link.aip.org/link/?APL/95/203303/1&agg=rss T. W. Ng, M. F. Lo, M. K. Fung, S. L. Lai, Z. T. Liu et al.<br/> While bulk heterojunctions (HJ) have been used in organic photovoltaic (OPV) devices, there are few studies on their interface electronics and mechanisms on device performance. Here, we studied the electronic structure of a mixed CuPc:C and a discrete CuPc/C junctions using photoemission spectroscop ... [Appl. Phys. Lett. 95, 203303 (2009)] published Wed Nov 18, 2009. Aggregates-induced dynamic negative differential resistance in conducting organic films http://link.aip.org/link/?APL/95/203302/1&agg=rss Xian Ning Xie, Junzhong Wang, Kian Ping Loh, and Andrew Thye Shen Wee<br/> This letter reports the negative differential resistance (NDR) behavior of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride films induced by aggregate formation in the film. It is observed that aggregate-states in the energy gap can by-pass the common charge conduction mode, and electron injec ... [Appl. Phys. Lett. 95, 203302 (2009)] published Wed Nov 18, 2009. Effects of the alkyl chain length in phosphonic acid self-assembled monolayer gate dielectrics on the performance and stability of low-voltage organic thin-film transistors http://link.aip.org/link/?APL/95/203301/1&agg=rss Kenjiro Fukuda, Takanori Hamamoto, Tomoyuki Yokota, Tsuyoshi Sekitani, Ute Zschieschang et al.<br/> We have fabricated pentacene organic thin-film transistors (TFTs) using self-assembled monolayers (SAMs) based on alkyl-phosphonic acids with five different alkyl chain lengths as the gate dielectric and investigated the relationship between the SAM chain length and the electrical performance and st ... [Appl. Phys. Lett. 95, 203301 (2009)] published Mon Nov 16, 2009. Improving optical performance of inverted organic solar cells by microcavity effect http://link.aip.org/link/?APL/95/193301/1&agg=rss Yongbing Long<!--orlang--> (&#x9F99;&#x62E5;&#x5175;)<!--orlang--><br/> Optical simulations have been performed to investigate the performance of inverted organic solar cells with metal-mirror microcavity structure formed by central active layer sandwiched between semitransparent silver (Ag) cathode and thick Ag anode. Compared to nearly optimized noncavity devices with ... [Appl. Phys. Lett. 95, 193301 (2009)] published Wed Nov 11, 2009. Chemical changes on the green emitter tris(8-hydroxy-quinolinato)aluminum during device aging of p-i-n-structured organic light emitting diodes http://link.aip.org/link/?APL/95/183309/1&agg=rss Sebastian Scholz, Bjorn Lussem, and Karl Leo<br/> Metal organic fluorescent and phosphorescent emitters are widely used in organic light emitting devices (OLEDs). Iridium-based triplet emitters are known to undergo chemical reactions with other materials during OLED aging. The material tris(8-hydroxy-quinolinato)aluminum (Alq), which is widely used ... [Appl. Phys. Lett. 95, 183309 (2009)] published Fri Nov 6, 2009. Influence of molecular weight on the solar cell performance of double-crystalline donor-acceptor block copolymers http://link.aip.org/link/?APL/95/183308/1&agg=rss Michael Sommer, Sven Huttner, Ullrich Steiner, and Mukundan Thelakkat<br/> We investigate the influence of the molecular weight of double-crystalline donor-acceptor block copolymers comprised of poly(3-hexylthiophene) as donor and poly(perylene bisimide acrylate) as acceptor segments on the device performance of polymer solar cells. Two block copolymers 1 and 2 exhibiting ... [Appl. Phys. Lett. 95, 183308 (2009)] published Fri Nov 6, 2009. Stable and reversible optoelectrical dual-mode data storage based on a ferrocenlylspiropyran molecule http://link.aip.org/link/?APL/95/183307/1&agg=rss Ying Ma, Chengshan Niu, Yongqiang Wen, Guo Li, Jingxia Wang et al.<br/> A spiropyran molecule bonded with ferrocene (SPFc) was synthesized as data storage medium. Optical recording pattern was obtained through the reversible modulation of UV and visible light on the SPFc film, which exhibited good reversibility compared with the spiropyran without ferrocene moiety. In a ... [Appl. Phys. Lett. 95, 183307 (2009)] published Thu Nov 5, 2009. Studies of charge transfer processes across donor-acceptor interface using a field effect transistor geometry http://link.aip.org/link/?APL/95/183306/1&agg=rss Manohar Rao and K. S. Narayan<br/> The existence of donor-type polymer field effect transistors (FETs), which are FETs exhibiting p-type characteristics and acceptor-type molecular FETs with n-type characteristics, provide an interesting possibility of a combined active bilayer system, especially under photoexcitation. We present a d ... [Appl. Phys. Lett. 95, 183306 (2009)] published Thu Nov 5, 2009. Oxidation of silver electrodes induces transition from conventional to inverted photovoltaic characteristics in polymer solar cells http://link.aip.org/link/?APL/95/183301/1&agg=rss Jong Bok Kim, Chang Su Kim, Youn Sang Kim, and Yueh-Lin Loo<br/> Oxidation of silver top electrodes in polymer solar cells induces the devices to exhibit a transition from conventional to inverted photovoltaic characteristics. As silver oxidizes, its work function increases from 4.3 to 5.0 eV. The silver top electrode thus reverts from collecting electrons to col ... [Appl. Phys. Lett. 95, 183301 (2009)] published Tue Nov 3, 2009. Low voltage operation in picene thin film field-effect transistor and its physical characteristics http://link.aip.org/link/?APL/95/183302/1&agg=rss Yumiko Kaji, Naoko Kawasaki, Xuesong Lee, Hideki Okamoto, Yasuyuki Sugawara et al.<br/> Low voltage operation of picene thin film field-effect transistor (FET) has been realized with 40 nm thick SiO gate dielectrics coated by two polymers, Cytop and polystyrene. The picene FETs operated in low absolute gate voltage |V| below 15 V for Cytop coated SiO and 30 V for polystyrene coated SiO ... [Appl. Phys. Lett. 95, 183302 (2009)] published Tue Nov 3, 2009. Optical confirmation of biaxial nematic (N) phase in a bent-core mesogen http://link.aip.org/link/?APL/95/183304/1&agg=rss Yun Jang, Vitaly P. Panov, Antoni Kocot, J. K. Vij, A. Lehmann et al.<br/> A bent-core mesogen with different end groups has been studied for different surface conditions in both planar and homeotropic cells using techniques for measuring biaxiality and optical switching. Biaxial nematic phase observed in between the uniaxial nematic and smectic phases is evidenced by a sh ... [Appl. Phys. Lett. 95, 183304 (2009)] published Tue Nov 3, 2009. Low-density band-gap states in pentacene thin films probed with ultrahigh-sensitivity ultraviolet photoelectron spectroscopy http://link.aip.org/link/?APL/95/183303/1&agg=rss Tomoki Sueyoshi, Hirohiko Fukagawa, Masaki Ono, Satoshi Kera, and Nobuo Ueno<br/> We detected a very low density of electronic states in the band gap of a nondoped pentacene thin film by using ultraviolet photoelectron spectroscopy with ultrahigh sensitivity and ultralow background. The gap states, which may originate from the highest occupied molecular orbital (HOMO) state in im ... [Appl. Phys. Lett. 95, 183303 (2009)] published Tue Nov 3, 2009. Singlet energy transfer and singlet-singlet annihilation in light-emitting blends of organic semiconductors http://link.aip.org/link/?APL/95/183305/1&agg=rss A. Ruseckas, J. C. Ribierre, P. E. Shaw, S. V. Staton, P. L. Burn et al.<br/> Excitation energy transfer from host to guest is studied in spin-cast blends of 4,4-bis(N-carbazolyl)biphenyl (CBP) and a phosphorescent fac-tris(2-phenylpyridyl)iridium(III)-cored dendrimer using time resolved fluorescence. The kinetics of energy transfer are consistent with homogeneous dispersion ... [Appl. Phys. Lett. 95, 183305 (2009)] published Tue Nov 3, 2009. Photocurrent enhancement in polymer:fullerene bulk heterojunction solar cells doped with a phosphorescent molecule http://link.aip.org/link/?APL/95/173304/1&agg=rss Barry P. Rand, Claudio Girotto, Alexander Mityashin, Afshin Hadipour, Jan Genoe et al.<br/> We demonstrate photocurrent enhancement of up to 20% in polymer:fullerene bulk heterojunction photovoltaic cells via the incorporation of a phosphorescent dopant, without degradation in the open-circuit voltage or fill factor of the device. The enhancement is shown to originate from multiple sources ... [Appl. Phys. Lett. 95, 173304 (2009)] published Fri Oct 30, 2009. In vacuo measurement of the sensitivity limit of planar Bragg grating sensors for monolayer detection http://link.aip.org/link/?APL/95/173306/1&agg=rss Richard M. Parker, James C. Gates, Martin C. Grossel, and Peter G. R. Smith<br/> An exposed Bragg grating incorporated into a planar waveguide was used to form an optical device that acts as a refractive index sensor. The exposed evanescent field causes the Bragg peak to be sensitive to the refractive index of its surroundings. The corresponding shift in peak wavelength can be u ... [Appl. Phys. Lett. 95, 173306 (2009)] published Fri Oct 30, 2009. Exciton switching and Peierls transitions in hybrid inorganic-organic self-assembled quantum wells http://link.aip.org/link/?APL/95/173305/1&agg=rss K. Pradeesh, J. J. Baumberg, and G. Vijaya Prakash<br/> The switching behavior of exciton absorption and photoluminescence is systematically explored in hybrid inorganic-organic multiple quantum well structures, based on (CHNH)PbI thin films and single crystals. Two structural phases found between 15 and 75 degrees C, based on orthorhombic and monoclini ... [Appl. Phys. Lett. 95, 173305 (2009)] published Fri Oct 30, 2009. Thermal crosslinking of organic semiconducting polythiophene improves transverse hole conductivity http://link.aip.org/link/?APL/95/173307/1&agg=rss Ioana R. Gearba, Chang-Yong Nam, Ron Pindak, and C. T. Black<br/> Thermal crosslinking using a suitable radical initiator simultaneously improves electrical conductivity in the semiconducting polymer poly(3-hexylthiophene) and makes the material insoluble. Crosslinked polythiophene shows as much as a fivefold increase in hole conductivity across the film thickness ... [Appl. Phys. Lett. 95, 173307 (2009)] published Fri Oct 30, 2009. Electronegativity equalization model for interface barrier formation at reactive metal/organic contacts http://link.aip.org/link/?APL/95/173303/1&agg=rss J. X. Tang, Y. Q. Li, S. D. Wang, C. S. Lee, and S. T. Lee<br/> A general model based on electronegativity equalization method (EEM) is proposed for a quantitative formulation of barrier formation at reactive metal/organic interfaces. The present model predicts for molecular bonding formation a linear dependence of barrier heights on the degree of partial charge ... [Appl. Phys. Lett. 95, 173303 (2009)] published Thu Oct 29, 2009.