Organic Complementary Circuits: Remarkable Enhancement of Hole Transport in Top‐Gated N‐Type Polymer Field‐Effect Transistors by a High‐k Dielectric for Ambipolar Electronic Circuits (Adv. Mater. 40/2012)

Baeg, Kang‐,Jun,Khim, Dongyoon,Jung, Soon‐,Won,Kang, Minji,You, In‐,Kyu,Kim, Dong‐,Yu,Facchetti, Antonio,Noh, Yong‐,Young WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.40

<P>On page 5433, Yong‐Young Noh, Antonio Facchetti, Kang‐Jun Baeg, and co‐workers report that high performance ambipolar complementary inverters and ring oscillators are provided by a remarkable enhancement of both hole injection and transport for n‐channel dominant N2200 OFETs. The significant enhancement of hole mobility in N2200 OTFTs is attributed to the strong dipoles in fluorinated high‐k gate dielectric blend of P(VDF‐TrFE):PMMA. </P>

High-Quality Solution-Processed Metal-Oxide Gate Dielectrics Realized With a Photo-Activated Metal-Oxide Nanocluster Precursor

Jo, Jeong-Wan,Kim, Kyung-Tae,Facchetti, Antonio,Kim, Myung-Gil,Park, Sung Kyu IEEE 2018 IEEE electron device letters Vol.39 No.11

<P>High-quality solution-derived amorphous alumina ( <TEX>${a}$</TEX>-Al<SUB>2</SUB>O<SUB>3</SUB>) dielectric has been achieved with [Al <TEX>$_{\textsf {13}}{(}\mu _{\textsf {3}}$</TEX>-OH <TEX>${)}_{\textsf {6}}{(}\mu $</TEX>-OH)<SUB>18</SUB> (H<SUB>2</SUB>O)<SUB>24</SUB>](NO<SUB>3</SUB>)<SUB>15</SUB>(Al-13 nanocluster) as a precursor and a local structure-controllable activation process via deep-UV-induced photochemical activation. The synergetic combination of an Al-13 nanocluster precursor and high-energetic photochemical activation enables the formation of highly dense <TEX>${a}$</TEX>-Al<SUB>2</SUB>O<SUB>3</SUB> thin films <I>via</I> an efficient dissociation and rearrangement of the nanocluster skeleton. The electrical characteristics of the nanocluster-based <TEX>${a}$</TEX>-Al<SUB>2</SUB>O<SUB>3</SUB> thin films were investigated in terms of their operative electronic conduction mechanism by comparing conventional nitrate-based and vacuum-deposited films. From these results, it was found that the leakage current density of solution-processed <TEX>${a}$</TEX>-Al<SUB>2</SUB>O<SUB>3</SUB> layers is largely affected by their precursor structures. Finally, to demonstrate the versatility of the high-quality nanocluster-based <TEX>${a}$</TEX>-Al<SUB>2</SUB>O<SUB>3</SUB> dielectrics, carbon nanotube and metal-oxide thin-film transistors were fabricated on low thermal budget stretchable and rigid substrates, respectively.</P>

Role of Gallium Doping in Dramatically Lowering Amorphous-Oxide Processing Temperatures for Solution-Derived Indium Zinc Oxide Thin-Film Transistors

Jeong, Sunho,Ha, Young-Geun,Moon, Jooho,Facchetti, Antonio,Marks, Tobin J. WILEY-VCH Verlag 2010 Advanced Materials Vol.22 No.12

<B>Graphic Abstract</B> <P>Ga doping in indium zinc oxide (IZO)-based amorphous-oxide semiconductors (AOSs) promotes the formation of oxide-lattice structures with oxygen vacancies at low annealing temperatures, which is essential for acceptable thin-film-transistor performance (see figure). The mobility dependence on annealing temperature and AOS composition are analyzed and the chemical role of Ga is clarified, as required for solution-processed, low-temperature-annealed AOSs. <img src='wiley_img_2010/09359648-2010-22-12-ADMA200902450-content.gif' alt='wiley_img_2010/09359648-2010-22-12-ADMA200902450-content'> </P>

Anthracenedicarboximide-based semiconductors for air-stable, <i>n</i>-channel organic thin-film transistors: materials design, synthesis, and structural characterization

Usta, Hakan,Kim, Choongik,Wang, Zhiming,Lu, Shaofeng,Huang, Hui,Facchetti, Antonio,Marks, Tobin J. The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.10

<P>A family of six <I>n</I>-channel organic semiconductors (<B>1–6</B>) based on the <I>N</I>,<I>N</I>′-dialkyl-2,3:6,7-anthracenedicarboximide (ADI) core was synthesized and characterized. These new semiconductors are functionalized with <I>n</I>-octyl (-<I>n</I>-C<SUB>8</SUB>H<SUB>17</SUB>), 1<I>H</I>,1<I>H</I>-perfluorobutyl (-<I>n</I>-CH<SUB>2</SUB>C<SUB>3</SUB>F<SUB>7</SUB>), cyano (–CN), and bromo (–Br) substituents, which results in wide HOMO and LUMO energy variations (∼1 eV) but negligible optical absorbance (<I>λ</I><SUB>max</SUB> = 418–436 nm) in the visible region of the solar spectrum. Organic thin-film transistors (OTFTs) were fabricated <I>via</I> semiconductor vapor-deposition, and the resulting devices exhibit exclusively electron transport with good carrier mobilities (<I>μ</I><SUB>e</SUB>) of 10<SUP>−3</SUP> to 0.06 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>. Within this semiconductor family, cyano core-substitution plays a critical role in properly tuning the LUMO energy to enable good electron transport in ambient conditions while maintaining a low level of ambient doping (<I>i.e.</I>, low <I>I</I><SUB>off</SUB>). Core-cyanated ADIs <B>3</B> and <B>6</B> exhibit air-stable TFT device operation with electron mobilities up to 0.04 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> in air. Very high current on/off ratios of >10<SUP>7</SUP> are measured with positive threshold voltages (<I>V</I><SUB>th</SUB> = 5–15 V) and low off currents (<I>I</I><SUB>off</SUB> = 10<SUP>−9</SUP> to 10<SUP>−12</SUP> A). Single-crystal structures of <I>N</I>,<I>N</I>′-1<I>H</I>,1<I>H</I>-perfluorobutyl ADIs <B>5</B> and <B>6</B> exhibit slipped-stack cofacial crystal packing with close π–π stacking distances of ∼3.2 Å. Additionally, close intermolecular interactions between imide-carbonyl oxygen and anthracene core-hydrogen are identified, which lead to the assembly of highly planar lamellar layers. Analysis of the air-stability of <B>1–6</B> thin films suggests that air-stability is mainly controlled by the LUMO energetics, and an electrochemical threshold of <I>E</I><SUB>red1</SUB> = −0.3 to −0.4 V is estimated to stabilize <I>n</I>-channel transport in this family of materials.</P> <P>Graphic Abstract</P><P>A new family of six air-stable <I>n</I>-channel organic semiconductors based on the <I>N</I>,<I>N</I>′-dialkyl-2,3:6,7-anthracenedicarboximide core has been synthesized and fully characterized. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm14713g'> </P>

Naphthalene diimide-based polymeric semiconductors. Effect of chlorine incorporation and n-channel transistors operating in water

Ryu, Gi-Seong,Chen, Zhihua,Usta, Hakan,Noh, Yong-Young,Facchetti, Antonio Cambridge University Press (Materials Research Soc 2016 MRS Communications Vol.6 No.1

<▼1><B>Abstract</B><P/></▼1><▼2><P>We demonstrate here the design, synthesis and characterization of two new chlorinated polymers, P(NDI2HD-T2Cl2) and P(NDI2OD-T2Cl2) based on <I>N,N</I>′-difunctionalized naphthalene diimide (NDI) and 3,3′-dichloro-2,2′-bithiophene (T2Cl2) moieties. Our results indicate that organic thin-film transistors (OTFTs) based on these new chlorinated polymers exhibit electron mobilities approaching 0.1 cm<SUP>2</SUP>V<SUP>−1</SUP>s<SUP>−1</SUP> (<I>I</I>on:<I>I</I>off ~ 10<SUP>6</SUP>-10<SUP>7</SUP>), with far less ambipolarity due to their lower highest occupied molecular orbital energies, and they are more stable under deleterious high-humidity conditions (RH ~ 60%) and upon submersion in water, compared with those fabricated with the parent non-chlorinated polymers. In addition, OTFTs fabricated with the new chlorinated polymers exhibit excellent operational stabilities with <3% degradations upon bias-stress test.</P></▼2>

Solution-Processable BODIPY-Based Small Molecules for Semiconducting Microfibers in Organic Thin-Film Transistors

Ozdemir, Mehmet,Choi, Donghee,Kwon, Guhyun,Zorlu, Yunus,Cosut, Bunyemin,Kim, Hyekyoung,Facchetti, Antonio,Kim, Choongik,Usta, Hakan American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.22

<P>Electron-deficient pi-conjugated small molecules can function as electron-transporting semiconductors in various optoelectronic applications. Despite their unique structural, optical, and electronic properties, the development of BODIPY-based organic semiconductors has lagged behind that of other pi-deficient units. Here, we report the design and synthesis of two novel solution-proccessable BODIPY-based small molecules (BDY-3T-BDY and BDY-4T-BDY) for organic thin-film transistors (OTFTs). The new semiconductors were fully characterized by H-1/C-13 NMR, mass spectrometry, cyclic voltammetry, UV-vis spectroscopy, photoluminescence, differential scanning calorimetry, and thermogravimetric analysis. The single-crystal X-ray diffraction (XRD) characterization of a key intermediate reveals crucial structural properties. Solution-sheared top-contact/bottom-gate OTFTs exhibited electron mobilities up to 0.01 cm(2)/V center dot s and current on/off ratios of >10(8). Film microstructural and morphological characterizations indicate the formation of relatively long (similar to 0.1 mm) and micrometer-sized (1-2 mu m) crystalline fibers for BDY-4T-BDY-based films along the shearing direction. Fiber-alignment-induced charge-transport anisotropy (mu?/mu approximate to 10) was observed, and higher mobilities were achieved when the microfibers were aligned along the conduction channel, which allows for efficient long-range charge-transport between source and drain electrodes. These OTFT performances are the highest reported to date for a BODIPY-based molecular semiconductor, and demonstrate that BODIPY is a promising building block for enabling solution-processed, electron-transporting semiconductor films.</P>

High Performance and Stable N-Channel Organic Field-Effect Transistors by Patterned Solvent-Vapor Annealing

Khim, Dongyoon,Baeg, Kang-Jun,Kim, Juhwan,Kang, Minji,Lee, Seung-Hoon,Chen, Zhihua,Facchetti, Antonio,Kim, Dong-Yu,Noh, Yong-Young American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.21

<P>We report the fabrication of high-performance, printed, <I>n</I>-channel organic field-effect transistors (OFETs) based on an <I>N</I>,<I>N</I>-dialkyl-substituted-(1,7&1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) derivative, PDI-RCN2, optimized by the solvent-vapor annealing (SVA) process. We performed a systematic study on the influence of solubility and the chemical structure of a solvent used for the SVA process on the ordering and orientation of PDI-RCN2 molecules in the thin film. The PDI-RCN2 film showed improved crystallinity under vapor annealing with the aliphatic 1,2-dichloroethane (DCE) as a marginal solvent. The <I>n</I>-type OFETs with DCE-vapor-annealed PDI-RCN2 show highly improved charge-carrier mobility of ∼0.5 cm<SUP>2</SUP> V<SUP>–1</SUP> s<SUP>–1</SUP> and higher stability under gate bias stress than the pristine OFETs. This large performance improvement was mainly attributed to increased crystallinity of the semiconductor thin film, enhancing π–π stacking. We also introduced a new method to pattern crystallinity of a certain region in the semiconducting film by selective exposure to the solvent vapor using a shadow mask. The crystal-patterned PDI-RCN2 OFETs exhibit decreased off-currents by ∼10× and improved gate bias stability by minimizing crosstalk, reducing leakage current between devices, and reducing the density of charge trap states of the organic semiconductor.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-21/am4029075/production/images/medium/am-2013-029075_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am4029075'>ACS Electronic Supporting Info</A></P>

Low-Temperature Solution-Processed Amorphous Indium Tin Oxide Field-Effect Transistors

Kim, Hyun Sung,Kim, Myung-Gil,Ha, Young-Geun,Kanatzidis, Mercouri G.,Marks, Tobin J.,Facchetti, Antonio American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.31

<P>Amorphous indium tin oxide (ITO)-based thin-film transistors (TFTs) were fabricated on various dielectrics [SiO(2) and self-assembled nanodielectrics (SANDs)] by spin-coating an ITO film precursor solution consisting of InCl(3) and SnCl(4) as the sources of In(3+) and Sn(4+), respectively, methoxyethanol (solvent), and ethanolamine (base). These films can be annealed at temperatures T(a) < or = 250 degrees C and afford devices with excellent electrical characteristics. The optimized [In(3+)]/[In(3+) + Sn(4+)] molar ratio (0.7) and annealing temperature (T(a) = 250 degrees C) afford TFTs exhibiting electron mobilities of approximately 2 and approximately 10-20 cm(2) V(-1) s(-1) with SiO(2) and SAND, respectively, as the gate dielectric. Remarkably, ITO TFTs processed at 220 degrees C still exhibit electron mobilities of >0.2 cm(2) V(-1) s(-1), which is encouraging for processing on plastic substrates.</P>

Spray-printed organic field-effect transistors and complementary inverters

Khim, D.,Baeg, K. J.,Yu, B. K.,Kang, S. J.,Kang, M.,Chen, Z.,Facchetti, A.,Kim, D. Y.,Noh, Y. Y. Royal Society of Chemistry 2013 Journal of Materials Chemistry C Vol.1 No.7

Charge Injection Engineering of Ambipolar Field-Effect Transistors for High-Performance Organic Complementary Circuits

Baeg, Kang-Jun,Kim, Juhwan,Khim, Dongyoon,Caironi, Mario,Kim, Dong-Yu,You, In-Kyu,Quinn, Jordan R.,Facchetti, Antonio,Noh, Yong-Young American Chemical Society 2011 ACS APPLIED MATERIALS & INTERFACES Vol.3 No.8

<P>Ambipolar π-conjugated polymers may provide inexpensive large-area manufacturing of complementary integrated circuits (CICs) without requiring micro-patterning of the individual p- and n-channel semiconductors. However, current-generation ambipolar semiconductor-based CICs suffer from higher static power consumption, low operation frequencies, and degraded noise margins compared to complementary logics based on unipolar p- and n-channel organic field-effect transistors (OFETs). Here, we demonstrate a simple methodology to control charge injection and transport in ambipolar OFETs via engineering of the electrical contacts. Solution-processed caesium (Cs) salts, as electron-injection and hole-blocking layers at the interface between semiconductors and charge injection electrodes, significantly decrease the gold (Au) work function (∼4.1 eV) compared to that of a pristine Au electrode (∼4.7 eV). By controlling the electrode surface chemistry, excellent p-channel (hole mobility ∼0.1–0.6 cm<SUP>2</SUP>/(Vs)) and n-channel (electron mobility ∼0.1–0.3 cm<SUP>2</SUP>/(Vs)) OFET characteristics with the same semiconductor are demonstrated. Most importantly, in these OFETs the counterpart charge carrier currents are highly suppressed for depletion mode operation (<I>I</I><SUB>off</SUB> < 70 nA when <I>I</I><SUB>on</SUB> > 0.1–0.2 mA). Thus, high-performance, truly complementary inverters (high gain >50 and high noise margin >75% of ideal value) and ring oscillators (oscillation frequency ∼12 kHz) based on a solution-processed ambipolar polymer are demonstrated.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2011/aamick.2011.3.issue-8/am200705j/production/images/medium/am-2011-00705j_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am200705j'>ACS Electronic Supporting Info</A></P>