Query: Solution-processed pseudo-vertical organic transistors based on TIPS-pentacene

Candidate papers:

abstract: Abstract Powerful and versatile transistors are indispensable to realize the vision of future flexible electronics, e.g. for wearable active matrix displays, smart sensors, or RFID tags. Organic thin film transistors are considered to be a perfect match for flexible electronics. However, conventional organic thin film transistors (OTFTs) still do not match the demanding performance targets of many applications. Furthermore, often complex and expensive fabrication steps are employed for the fabrication of hero devices, which is not compatible with the paradigm of low cost production of flexible electronics. In this contribution, we present the first solution processed vertical organic field effect transistor (VOFET) with good on state performance comparable to vacuum processed VOFETs. This approach unites the advantages of a low temperature, low cost solution processing with an ultra short channel transistor concept possibly enabling large area, low cost flexible electronics. We examine the influence of different crystal morphologies (spherulitic, ribbons) on the transistor performance by using spin and shear coating as solution based deposition methods. The solution processed VOFETs reach channel width normalized transconductances of up to 0.26 mS/mm with a charge carrier mobility of 4.8 cm2/Vs. S parameter measurements finally verify that transition frequencies up to 6 MHz are reachable with shear coated TIPS pentacene. However, compared to small molecule based VOFETs, the solution processed VOFETs show an unfavorably high off state current and hysteresis which are explained by background doping and charge carrier trapping. Hence, in order to advance with, further optimization of the semiconductor material and the insulator semiconductor interface are thus required to qualify solution processed VOFETs for commercial applications.
author_names: David Kneppe

Felix Talnack

Bahman Kheradmand Boroujeni

Cecilia Teixeira da Rocha

Marc Hoppner

Alexander Tahn

Stefan C B Mannsfeld

Frank Ellinger

Karl Leo

Hans Kleemann
title: Solution processed pseudo vertical organic transistors based on TIPS pentacene
year: 2021

abstract: The development of nonvolatile organic field effect transistor (OFET) memories with a satisfactory solution processability is highly desirable to fabricate the data storage media for flexible and printed electronic devices. In this study, we fabricate top gate/bottom contact OFET memories having an organic floating gate structure by a spin coating process and investigate their memory characteristics. An ambipolar polymer semiconductor of poly(N alkyldiketopyrrolo pyrrole dithienylthieno[3,2 b]thiophene) (DPP DTT) was used to fabricate an organic semiconductor layer, on which an organic composite of polystyrene and 6,13 bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) was deposited to form an organic floating gate structure through vertical phase separation. The existence of a deep lowest unoccupied molecular orbital (LUMO) level and the excellent electron transport property of the DPP DTT enables the injection of electrons from the Au source drain electrodes to the DPP DTT semiconductor layer and the storage of electrons in the LUMO level of the TIPS pentacene floating gates by programming under dark conditions. A high work function metal oxide layer of MoO3 was inserted at the Al gate electrode/CYTOP gate insulator interface to tune the energy level difference between the Au source drain and Al gate electrodes. The DPP DTT FET memories with MoO3/Al gate electrodes exhibit satisfactory retention characteristics and, because of the ambipolar trapping characteristics, allow the storing of holes in the highest occupied molecular orbital level of the TIPS pentacene floating gates in the erasing process. Furthermore, the molecular floating gate OFET memories exhibit a high storage capacity for multi level data, and four state levels can be recorded with stable retention characteristics.
author_names: Miho Higashinakaya

Takashi Nagase

Hayato Abe

Reitaro Hattori

Shion Tazuhara

Takashi Kobayashi

Hiroyoshi Naito
title: Electrically programmable multilevel nonvolatile memories based on solution processed organic floating gate transistors
year: 2021

abstract: Abstract In this study, we report a facile route to regulate the crystallization and enhance charge transport of small molecule organic semiconductors by blending with a rubbery polymer additive polyisobutylene (PIB) Using a solution processed semiconductor 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) to mix with the PIB polymer, we show that the addition of PIB led to densely arranged, lengthened TIPS pentacene needles with excellent long range uniformity. Bottom gate, top contact organic thin film transistors (OTFTs) based on TIPS pentacene/PIB hybrid film demonstrated a field effect mobility of up to 0.15 cm2/Vs, and particularly, a 3 fold and 2 fold enhancement of average mobility and performance consistency (denoted by average mobility to standard deviation ratio) In addition, the effect of hexamethyldisilazane (HMDS) surfactant treatment on the semiconductor charge transport was studied. We ascribe such improved performance of TIPS pentacene/PIB blend OTFTs to the collaborative outcome of reduced crystal misorientation, diminished defects and charge trap centers, as well as a higher areal coverage. The effective method as demonstrated in this work can be generally implemented to attune the crystal growth and promote charge transport of newly developed small molecule organic semiconductors.
author_names: Zhengran He

Ziyang Zhang

Sheng Bi

Kyeiwaa Asare-Yeboah

Jihua Chen

Dawen Li
title: A facile and novel route to improve TIPS pentacene based organic thin film transistor performance with elastomer
year: 2020

abstract: The blending of the crystalline organic semiconductor, 6,13 bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) with amorphous polymers exhibits not only excellent solution processability, but also superior performance characteristics in organic thin film transistors (OTFTs) To understand the inkjet printing behavior of TIPS pentacene/polymer blends, we use amorphous polycarbonate (APC) which is structurally beneficial to the facile phase separation of TIPS pentacene crystals due to the strong segregation strength estimated by the Flory Huggins interaction parameter. The various inkjet printing behaviors of TIPS pentacene/APC inks, which depend on the TIPS pentacene/APC compositions, ink viscosities, and different solvent mixtures, are investigated. These behaviors can ultimately determine the phase separation, morphology, shape, and orientation of the TIPS pentacene crystals in OTFT films. Flory Huggins phase separation theory is applied, and various analytical methods, such as polarized optical microscopy, 3D surface profile, and time of flight secondary ion mass spectroscopy (TOF SIMS) are utilized to explain these relationships. By controlling these inkjet printing conditions, it is possible to easily regulate the optimal inkjet printing process for TIPS pentacene/polymer systems, which can derive the desirable stripe shaped and vertically phase separated TIPS pentacene crystals with the proper orientation and enhanced surface morphology. The resultant inkjet printed films from the TIPS pentacene with APC show excellent device stability and an average mobility of 0.53 cm2 V 1 s 1. Furthermore, the inkjet printed flexible OTFT array with an average mobility of 0.27 cm2 V 1 s 1 sustains the application of TIPS pentacene/APC in the field of flexible printed electronics.
author_names: Song Yun Cho

J M Ko

Jongsun Lim

Jun Young Lee

Changjin Lee
title: Inkjet printed organic thin film transistors based on TIPS pentacene with insulating polymers
year: 2013

abstract: In this study, we demonstrated for the first time that a metal containing semicrystalline polymer was used as an additive to mediate the thin film morphology of solution grown, small molecule organic semiconductors. By mixing polyferrocenylsilane (PFS) with an extensively studied organic semiconductor 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) PFS as a semicrystalline polymer independently forms nucleation and crystallization while simultaneously ameliorating diffusivity of the blend system and tuning the surface energies as a result of its partially amorphous property. We discovered that the resultant blend film exhibited a 6 fold reduction in crystal misorientation angle and a 3 fold enlargement in average grain width. Enhanced crystal orientation considerably reduces mobility variation, while minimized defects and trap centers located at grain boundaries lessen the adverse impact on the charge transport. Consequently, bottom gate, top contact organic thin film transistors (OTFTs) based on the TIPS pentacene/PFS mixture yielded a 40% increase in performance consistency (represented by the ratio of average mobility to the standard deviation of mobility) The PFS semicrystalline polymer controlled crystallization can be used to regulate the thin film morphology of other high performance organic semiconductors and shed light on applications in organic electronic devices.
author_names: Zhengran He

Ziyang Zhang

Kyeiwaa Asare-Yeboah

Sheng Bi

Jihua Chen

Dawen Li
title: Polyferrocenylsilane Semicrystalline Polymer Additive for Solution Processed p Channel Organic Thin Film Transistors
venue: Polymers
year: 2021

abstract: Despite solution processed organic semiconductors have attracted much research attention, the randomized crystallization and large prevalence of grain boundary remain as a challenge to realize high performance organic electronic applications. In this work, we report the incorporation of poly(butyl acrylate) polymer additive with organic semiconductors with the mediation of a solvent vapor annealing method in order to modify the nucleation and crystal growth process. As 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was experimented as a benchmark semiconductor, we demonstrated that the TIPS pentacene/poly(butyl acrylate) mixture exhibits rigidly aligned crystals, large grain width and improved areal coverage. In particular, thin film morphological characterization indicated a substantial reduction in misorientation angle by approximately two orders of magnitude as well as a 5 fold enlargement of grain width. A grain boundary model is proposed as a theoretic basis to understand the connection between grain width and hole mobility. Bottom gate, top contact thin film transistors based on TIPS pentacene/poly(butyl acrylate) blends demonstrated enhanced hole mobility of up to 0.11 cm2/Vs.
author_names: Yeqing Sun

Ziyang Zhang

Kyeiwaa Asare-Yeboah

Sheng Bi

Zhengran He
title: Large Dimensional Organic Semiconductor Crystals with Poly(butyl acrylate) Polymer for Solution Processed Organic Thin Film Transistors
venue: Electronic Materials Letters
year: 2020

abstract: Electrolyte gated organic field effect transistors (EGOFETs) have been fabricated using 6,13 Bis (triisopropyl silylethynyl) pentacene (TIPS pentacene) as an organic semiconductor active material. Despite the organic semiconductor being deposited in air by drop casting, our EGOFETs showed performance comparable with state of the art technologies, and devices kept their functionalities while gated with saline solution at 37 degC for several days. In addition, the biocompatibility of the material was successfully investigated, promoting the use of TIPS pentacene based EGOFETs for biosensing applications.
author_names: Nicolo Lago

Marco Buonomo

Saima Imran

Roberta Bertani

Nicola Wrachien

Mario Bortolozzi

Morten G Pedersen

Andrea Cester
title: TIPS Pentacene as Biocompatible Material for Solution Processed High Performance Electronics Operating in Water
venue: IEEE Electron Device Letters
year: 2018

abstract: Abstract In this study, we achieved high performance organic small molecule transistors by using roll to roll slot die coating technique and polymer dielectric layers. By carefully controlling the coating conditions, highly ordered single crystalline thin films could be achieved. Hence, the organic thin film transistor (OTFT) device exhibited an average mobility of 4.2 cm2V 1s 1 and maximum mobility of 6.5 cm2V 1s 1 based on polystyrene (PS) dielectric layer in the ambient air condition, which is among the best values for TIPS pentacene based devices. The thin film morphology, crystallinity, and optical properties were studied in details. A complementary inverter based on p type TIPS pentacene and n type 6,13 Dicyano pentacene 2,3:9,10 bis(dicarboximide) (PDI CN) with a high voltage gain of 54 was achieved. Finally, the flexible devices based on roll to roll slot die coated PS dielectric and TIPS pentacene were achieved with a charge carrier mobility of 1.2 cm2V 1s 1.
author_names: Zhenhua Lin

Xing Guo

Long Zhou

Chunfu Zhang

Jingjing Chang

Jishan Wu

Jie Zhang
title: Solution processed high performance organic thin film transistors enabled by roll to roll slot die coating technique
year: 2018

abstract: We demonstrated an organic and oxide hybrid CMOS inverter with the solution processed semiconductor and source/drain electrodes. For the solution processed n and p type semiconductor, InGaZnO solution and TIPS pentacene/PaMS blend were spin coated respectively while Silver ink and PEDOT:PSS solution were drop casted with the help of the bank to serve as source/drain electrodes. The InGaZnO and the TIPS pentacene transistors show typical n and p type transistor operations with low off current. Based on the combination of the solution processed n and p type transistors, full swing characteristic curve with low static current of the hybrid CMOS were obtained.
author_names: Sunghun Lee

Min-Jae Seo

Amos Amoako Boampong

Jae-Hyeok Cho

Kyeong Min Yu

Min-Hoi Kim
title: Solution Processed Organic and Oxide Hybrid CMOS Inverter for Low Cost Electronic Circuits.
venue: Journal of nanoscience and nanotechnology
year: 2020

abstract: We demonstrated a new type of a solution processed organic field effect transistor (OFET) in a bottom gate, top contact geometry where low leakage current and self pattern registration were achieved using a patterned dielectric barrier (PDB) The PDB of a hydrophobic fluorinated polymer was produced on the top of a polymeric gate insulator of poly(4 vinylphenyl) by transfer printing. The PDB enables to effectively screen out the vertical charge flow generated from the gate electrode, and thus the vertical leakage current between the gate and the drain was reduced by two orders of the magnitude compared to the leakage current in a conventional OFET without the PDB. Moreover, the PDB defines spontaneously an active channel pattern from a solution of 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS PEN) by means of the selective wettability and the geometrical confinement.
author_names: Changmin Keum

Jin-Hyuk Bae

Min-Hoi Kim

Won-Suk Choi

Sin Doo Lee
title: Solution processed low leakage organic field effect transistors with self pattern registration based on patterned dielectric barrier
year: 2012