Organic semiconductor

About: Organic semiconductor is a research topic. Over the lifetime, 15905 publications have been published within this topic receiving 533881 citations.

High-performance polymer heterojunction solar cells of a polysilafluorene derivative

Abstract: High-performance polymer heterojunction solar cells fabricated from an alternating copolymer of 2,7-silafluorene (SiF) and 4,7-di(2′-thienyl)-2,1,3-benzothiadiazole (DBT) (PSiF-DBT) as the electron donor blended with [6,6]-phenyl-C61-butyric acid methyl ester as the electron acceptor were investigated. A power-conversion efficiency up to 5.4% with an open-circuit voltage of 0.90V, a short-circuit current of 9.5mAcm−2, and a fill factor of 50.7% was achieved under the illumination of AM 1.5G from a calibrated solar simulator (800Wm−2). The field-effect transistors fabricated from PSiF-DBT showed a high hole mobility of ∼1×10−3cm2V−1s−1.

Fabrication of bulk heterojunction plastic solar cells by screen printing

Abstract: We demonstrate the use of screen printing in the fabrication of ultrasmooth organic-based solar cells. Organic films on the order of several tens of nanometers in thickness and 2.6 nm surface roughness were made. The first-generation screen-printed plastic solar cells demonstrated 4.3% in power conversion efficiency when using an aluminum electrode and 488 nm illumination.

Laser action in organic semiconductor waveguide and double-heterostructure devices

Abstract: Stimulated emission by optical pumping of solid-state organic materials has been well known since the late 1960s following thefirst demonstrations of laser action in dye-doped gels and molecular crystals1,2,3,4. Interest in this field has been revived by the demonstration of efficient, long-lived and intense electroluminescence in both polymeric5 and small-molecular-weight6 organic thin films, which indicates the possibility of laser action in these materials. Several recent studies of optically pumped polymers have reported emission phenomena suggestive of laser action7,8,9. Here we present clear evidence for laser action from optically pumped, vacuum-deposited thin films of organic molecules, in both slab-waveguide and double-heterostructure configurations. This realization of laser action in conducting organic thin films should open the way to the development of a new class of electrically pumped laser diodes.

Threshold Voltage Shift in Organic Field Effect Transistors by Dipole-Monolayers on the Gate Insulator

Abstract: We demonstrate controllable shift of the threshold voltage and the turn-on voltage in pentacene thin film transistors and rubrene single crystal field effect transistors (FET) by the use of nine organosilanes with different functional groups. Prior to depositing the organic semiconductors, the organosilanes were applied to the SiO2 gate insulator from solution and form a self assembled monolayer (SAM). The observed shift of the transfer characteristics range from -2 to 50 V and can be related to the surface potential of the layer next to the transistor channel. Concomitantly the mobile charge carrier concentration at zero gate bias reaches up to 4*10^12/cm^2. In the single crystal FETs the measured transfer characteristics are also shifted, while essentially maintaining the high quality of the subthreshold swing. The shift of the transfer characteristics is governed by the built-in electric field of the SAM and can be explained using a simple energy level diagram. In the thin film devices, the subthreshold region is broadened, indicating that the SAM creates additional trap states, whose density is estimated to be of order 1*10^12/cm^2.

High-Mobility Field-Effect Transistors from Large-Area Solution-Grown Aligned C60 Single Crystals

Abstract: Field-effect transistors based on single crystals of organic semiconductors have the highest reported charge carrier mobility among organic materials, demonstrating great potential of organic semiconductors for electronic applications. However, single-crystal devices are difficult to fabricate. One of the biggest challenges is to prepare dense arrays of single crystals over large-area substrates with controlled alignment. Here, we describe a solution processing method to grow large arrays of aligned C60 single crystals. Our well-aligned C60 single-crystal needles and ribbons show electron mobility as high as 11 cm2V–1s–1 (average mobility: 5.2 ± 2.1 cm2V–1s–1 from needles; 3.0 ± 0.87 cm2V–1s–1 from ribbons). This observed mobility is ∼8-fold higher than the maximum reported mobility for solution-grown n-channel organic materials (1.5 cm2V–1s–1) and is ∼2-fold higher than the highest mobility of any n-channel organic material (∼6 cm2V–1s–1). Furthermore, our deposition method is scalable to a 100 mm wafer ...