Interfacial Effects of UV-Ozone Treated Sol-Gel Processable ZnO for Hybrid Photodetectors and Thin Film Transistors

MRS Advances ◽  
2019 ◽  
Vol 4 (31-32) ◽  
pp. 1793-1800 ◽  
Author(s):  
Alec Pickett ◽  
Aiswarya A. Mohapatra ◽  
Suman Ray ◽  
Christopher Robledo ◽  
Kartik Ghosh ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Sol Gel ◽  
High Mobility ◽  
Inorganic Materials ◽  
Zno Films ◽  
Type Semiconductor ◽  
Order Of Magnitude ◽  
Organic Photodetectors ◽  
Uv Ozone

ABSTRACTHybrid organic-inorganic semiconducting interfaces have attracted attention in photodiodes and field-effect transistors (FETs) due to the realization of intrinsic p-n junctions and their mechanical flexibility. With the difficulty of developing high-mobility n-type organic semiconductors due to the necessity of low LUMO levels and ambient environment stability, solution processable inorganic materials are an excellent alternative. ZnO is an intrinsic n-type semiconductor which is non-toxic and sol-gel processable, creating avenues for film patterning and fully solution processed devices. We report the improvement of electron mobilities in ZnO FETs through simple UV-Ozone processing which reduces lattice defects within the film and at the SiO2/ZnO interface. Treated ZnO films yield electron mobilities close to 10-2 cm2/Vs and on/off current ratios of 104 while non-treated films have mobilities on the order of 10-5 cm2/Vs and an order of magnitude lower on/off current ratios. Treated films also yield improved photoresponsivity and detectivity in hybrid ZnO-organic photodetectors.

scholarly journals Solution-Processed Organic and ZnO Field-Effect Transistors in Complementary Circuits

2021 ◽  
Vol 2 (2) ◽  
pp. 60-71
Author(s):  
John Barron ◽  
Alec Pickett ◽  
James Glaser ◽  
Suchismita Guha
Keyword(s):  
Field Effect ◽  
Vinylidene Fluoride ◽  
Field Effect Transistors ◽  
Sol Gel ◽  
Semiconductor Layer ◽  
Zno Films ◽  
Operating Voltage ◽  
Solution Processed ◽  
P Type ◽  
Uv Ozone

The use of high κ dielectrics lowers the operating voltage in organic field-effect transistors (FETs). Polymer ferroelectrics open the path not just for high κ values but allow processing of the dielectric films via electrical poling. Poled ferroelectric dielectrics in p-type organic FETs was seen to improve carrier mobility and reduce leakage current when compared to unpoled devices using the same dielectric. For n-type FETs, solution-processed ZnO films provide a viable low-cost option. UV–ozone-treated ZnO films was seen to improve the FET performance due to the filling of oxygen vacancies. P-type FETs were fabricated using the ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) as the dielectric along with a donor–acceptor polymer based on diketopyrrolopyrrole (DPP-DTT) as the semiconductor layer. The DPP-DTT FETs yield carrier mobilities upwards of 0.4 cm2/Vs and high on/off ratios when the PVDF-TrFE layer is electrically poled. For n-type FETs, UV–ozone-treated sol–gel ZnO films on SiO2 yield carrier mobilities of 10−2 cm2/Vs. DPP-DTT-based p- and ZnO-based n-type FETs were used in a complementary voltage inverter circuit, showing promising characteristic gain. A basic inverter model was used to simulate the inverter characteristics, using parameters from the individual FET characteristics.

Donor-acceptor copolymers and sol-gel processable zinc oxide for thin film transistors and hybrid photodetectors

2019 ◽  
Author(s):  
◽  
Alec Pickett
Keyword(s):  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
Sol Gel ◽  
Phenyl Group ◽  
Grazing Incidence ◽  
Second Phase ◽  
Commercial Development ◽  
University Of Missouri ◽  
Pi Conjugated ◽  
P Type

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Organic semiconductors have been gaining attention both in research and commercial development for electronic devices due to their low manufacturing and processing costs. Copolymers based on diketopyrrolopyrrole (DPP) cores have attracted a lot of attention due to their high p-type as well as n-type carrier mobilities in organic field-effect transistors (FETs) and high power conversion efficiencies in solar cell structures. Hybrid organic-inorganic photodiode interfaces have also gained significant interest due to the realization of intrinsic p-n junctions as well as their unique physical properties such as mechanical flexibility and high photosensitivity. ZnO is an intrinsic n-type semiconductor which is non-toxic and sol-gel processable, creating avenues for film patterning and fully solution processed devices. In this work, we report the structural and charge transport properties of n-dialkyl side-chain substituted thiophene DPP end-capped with a phenyl group (Ph-TDPP-Ph) monomer in FETs which were fabricated by vacuum deposition and solvent casting. From grazing incidence X-ray diffraction (GIXRD), Ph-TDPP-Ph reveals polymorphic structure with [pi]-conjugated stacking direction oriented in-plane. The unit cell comprises either one monomer for one phase (TR1), or two monomers for the second phase (TR2). The TR2 phase thus signals a shift from a coplanar to herringbone orientation of the molecules. The device performance is sensitive to the ratio of the two triclinic phases found in the film. Some of the best FET performances with p-type carrier mobilities of 0.1 cm2/Vs and on/off ratio of 10[superscript 6] are for films that comprise mainly the TR1 phase.

ChemInform Abstract: Air-Stable and High-Mobility Organic Semiconductors Based on Heteroarenes for Field-Effect Transistors

ChemInform ◽  
2011 ◽  
Vol 42 (42) ◽  
pp. no-no
Author(s):  
Shoji Shinamura ◽  
Itaru Osaka ◽  
Eigo Miyazaki ◽  
Kazuo Takimiya
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
Field Effect Transistors ◽  
High Mobility

scholarly journals Material Design Inputs from Charge Density Analysis in Organic Semiconductors

2014 ◽  
Vol 70 (a1) ◽  
pp. C1552-C1552
Author(s):  
Venkatesha Hathwar ◽  
Mads Jørgensen ◽  
Mattia Sist ◽  
Jacob Overgaard ◽  
Bo Iversen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Electron Density ◽  
Organic Semiconductors ◽  
Field Effect Transistors ◽  
High Mobility ◽  
Material Design ◽  
Detailed Comparison ◽  
Light Emitting ◽  
Density Analysis ◽  
P Type

In recent years, semiconducting organic materials have attracted a considerable amount of interest to develop all-organic or hybrid organic-inorganic electronic devices such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), or photovoltaic cells. Rubrene (5,6,11,12-tetraphenyltetracene, RUB) is one of the most explored compound in this area as it has nearly 100% fluorescence quantum efficiency in solution. Additionally, the OFET fabricated by vacuum-deposited using orthorhombic rubrene single crystals show p-type characteristics with high mobility up to 20cm2/Vs (Podzorov et al., 2004). The large charge-carrier mobilities measured have been attributed to the packing motif (Fig a) which provides enough spatial overlap of the π-conjugated tetracene backbone. In the same time, RUB undergoes an oxidation in the presence of light to form rubrene endoperoxide (RUB-OX) (Fumagalli et al., 2011). RUB-OX molecules show electronic and structural properties strikingly different from those of RUB, mainly due to the disruption in the conjugate stacking of tetracene moieties. The significant semiconducting property of RUB is not clear yet. In this context, high resolution single crystal X-ray data of RUB (Fig b) and RUB-OX have been collected at 100K. Owing to the presence of weak aromatic stacking and quadrupolar interactions, the neutron single crystal data is also collected at 100K. The C-H bond distances and scaled anisotropic displacement parameters (ADP) of hydrogens from the neutron experiment are used in the multipolar refinements of electron density. The chemical bonding features (Fig c), the topology of electron density and strength of weak interaction are calculated by the Atoms in Molecules (AIM) theory (Bader, 1990). It is further supported by the source function description and mapping of non-covalent interactions based on the electron density. The detailed comparison of two organic semiconductors, RUB and RUB-OX will be discussed.

Electrochemistry, a Useful Tool in the Synthesis of Oligothiophenes

2021 ◽  
Vol 25 ◽  
Author(s):  
Fabiana Pandolfi ◽  
Martina Bortolami ◽  
Marta Feroci ◽  
Leonardo Mattiello ◽  
Vincenzo Scarano ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Organic Semiconductors ◽  
Organic Solar Cells ◽  
Field Effect Transistors ◽  
Energy Levels ◽  
Organic Field Effect Transistors ◽  
Light Emitting ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Organic Photodetectors

: Thiophene derivatives, either "small molecules," oligomers or polymers, play a role of primary importance among organic semiconductors. Therefore they have numerous and different technological applications in the field of Organic Electronics. For this reason, thiophene-based materials are found in devices such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), organic solar cells (OSCs), organic photodetectors, and many others. Oligothiophenes and polythiophenes have in common excellent charge transport properties and synthetic procedures that are now well established. Furthermore, oligothiophenes do not possess the intrinsic disadvantages of polythiophenes, such as the lack of well-defined structures and the inevitable presence of impurities. Electrochemistry can give a significant contribution to the field of oligothiophenes not only by allowing the determination of the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) energy levels by the means of cyclic voltammetry (CV), but also rendering oligothiophenes syntheses more expeditious in comparison with the classical organic ones. This review outlines the application of electrochemistry techniques to the synthesis of oligothiophene derivatives.

Air-Stable and High-Mobility Organic Semiconductors Based on Heteroarenes for Field-Effect Transistors

Heterocycles ◽  
2011 ◽  
Vol 83 (6) ◽  
pp. 1187 ◽  
Author(s):  
Kazuo Takimiya ◽  
Shoji Shinamura ◽  
Itaru Osaka ◽  
Eigo Miyazaki
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
Field Effect Transistors ◽  
High Mobility

Three-Dimensional Organic Field-Effect Transistors: Charge Accumulation in their Vertical Semiconductor Channels

2009 ◽  
Vol 1154 ◽  
Author(s):  
M. Uno ◽  
I. Doi ◽  
K. Takimiya ◽  
Jun Takeya
Keyword(s):  
Organic Semiconductors ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Three Dimensional ◽  
High Mobility ◽  
Double Layers ◽  
Organic Field Effect Transistors ◽  
Output Current ◽  
Active Matrix ◽  
High Output

AbstractThree-dimensional organic field-effect transistors are developed with multiple vertical channels of organic semiconductors to gain high output current and high on-off ratio. High-mobility and air-stable dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene thin films deposited on horizontally elongated vertical sidewalls have realized unprecedented high output current per area of 2.6 A/cm2 with the application of drain voltage -10 V and gate voltage -20 V. The on-off ratio is as high as 2.7×106. Carrier mobility of the organic semiconductor deposited on the vertical sidewalls is typically 0.30 cm2/Vs. The structure is built also on plastic substrates, where still considerable current modulation is preserved with high output current per area of 70 mA/cm2 and with high on-off ratio of 8.7×106. The performance exceeds practical requirements for applications in driving organic light-emitting diodes in active-matrix displays. The technique of gating with electric double layers of ionic liquid is also introduced to the three-dimensional transistor structure.

scholarly journals Wafer-scale integration of stretchable semiconducting polymer microstructures via capillary gradient

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuchen Qiu ◽  
Bo Zhang ◽  
Junchuan Yang ◽  
Hanfei Gao ◽  
Shuang Li ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
High Performance ◽  
Field Effect Transistors ◽  
Solution Process ◽  
High Mobility ◽  
New Paradigm ◽  
Wafer Scale ◽  
Assembly Method ◽  
Polymer Microstructures ◽  
Scale Integration

AbstractOrganic semiconducting polymers have opened a new paradigm for soft electronics due to their intrinsic flexibility and solution processibility. However, the contradiction between the mechanical stretchability and electronic performances restricts the implementation of high-mobility polymers with rigid molecular backbone in deformable devices. Here, we report the realization of high mobility and stretchability on curvilinear polymer microstructures fabricated by capillary-gradient assembly method. Curvilinear polymer microstructure arrays are fabricated with highly ordered molecular packing, controllable pattern, and wafer-scale homogeneity, leading to hole mobilities of 4.3 and 2.6 cm2 V−1 s−1 under zero and 100% strain, respectively. Fully stretchable field-effect transistors and logic circuits can be integrated in solution process. Long-range homogeneity is demonstrated with the narrow distribution of height, width, mobility, on-off ratio and threshold voltage across a four-inch wafer. This solution-assembly method provides a platform for wafer-scale and reproducible integration of high-performance soft electronic devices and circuits based on organic semiconductors.

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