Hole Mobility Enhancement Research Articles

Colloidal Synthesis of P-Type Zn3As2 Nanocrystals.

Zinc pnictides, particularly Zn3As2, hold significant promise for optoelectronic applications owing to their intrinsic p-type behavior and appropriate bandgaps. However, despite the outstanding properties of colloidal Zn3As2 nanocrystals, research in this area is lacking because of the absence of suitable precursors, occurrence of surface oxidation, and intricacy of the crystal structures. In this study, a novel and facile solution-based synthetic approach is presented for obtaining highly crystalline p-type Zn3As2 nanocrystals with accurate stoichiometry. By carefully controlling the feed ratio and reaction temperature, colloidal Zn3As2 nanocrystals are successfully obtained. Moreover, the mechanism underlying the conversion of As precursors in the initial phases of Zn3As2 synthesis is elucidated. Furthermore, these nanocrystals are employed as active layers in field-effect transistors that exhibit inherent p-type characteristics with native surface ligands. To enhance the charge transport properties, a dual passivation strategy is introduced via phase-transfer ligand exchange, leading to enhanced hole mobilities as high as 0.089 cm2 V-1 s-1. This study not only contributes to the advancement of nanocrystal synthesis, but also opens up new possibilities for previously underexplored p-type nanocrystal research.

Fluorination of Star‐Shaped Cyclopenta[2,1‐b;3,4‐b′]dithiophene Derivatives and Its Application as Hole‐Transporting Materials in Scalable Perovskite Solar Cell Fabrication by Bar Coating

In this study, three novel star‐shaped small molecules HYC‐oF, HYC‐mF, and HYC‐H are designed and synthesized and are applied in perovskite solar cells (PSCs) as efficient hole‐transporting materials (HTMs). Compared with non‐fluorinated HYC‐H, F‐substituted analogs HYC‐oF and HYC‐mF exhibited enhanced hole mobility, suitable energy level alignment, improved interfacial contact and hole extraction/transport capability, better passivation effect, as well as increased hydrophobicity. PSC fabrication by spin‐coating this series of HYC‐oF, HYC‐mF, and HYC‐H molecules on a bar‐coated perovskite layer yielded PCEs values of 19.64%, 18.38%, and 16.98%, respectively. In order to realize a fully scalable PSC preparation process, sequential coating of HYC‐oF layer on perovskite layer all by thermal‐assisted bar‐coating (TABC) method was carried out on 10 × 10 cm2 area. The TABC‐based HYC‐oF layer had a compact and uniform morphology with full surface coverage on the TABC‐based perovskite film. Under optimized condition, the PSCs fabricated from such film exhibited a PCE of 18.49% as compared with a lower power conversion efficiency (PCE) of 17.51% from the reference cell using TABC‐based spiro‐OMeTAD. This work demonstrates the potential of fluorinated star‐shaped cyclopenta[2,1‐b;3,4‐b′]dithiophene (CPDT)‐based molecule as HTM for achieving efficient PSC in both small and large scale.

An alternating copolymer of phenothiazine and ethylenedioxythiophene for perovskite solar cells: effects of flexible and rigid substituent alternation.

Developing p-type polymeric semiconductors with exceptional electrical performance, heat tolerance, and cost-effectiveness is pivotal for advancing the practical application of n-i-p perovskite solar cells. Here, we employed direct arylation polycondensation to synthesize an alternating copolymer of phenothiazine and 3,4-ethylenedioxythiophene, featuring a high glass transition temperature (175 °C). In addition to the alternation of conjugated units within the main chain, the copolymer features alternating flexible (2-octyldodecyl) and rigid (trimethylphenyl) substituents at the nitrogen positions of the phenothiazine moiety. Compared to reference polymers with solely flexible or rigid substituents, the alternating use of these moieties resulted in the polymeric semiconductor composite film with smoother morphology and enhanced hole mobility. By employing this polymer with a distinct distribution of substituents and an innovative main chain structure as a hole transport material, we fabricated perovskite solar cells achieving an average efficiency of 25.1%. These cells also exhibited excellent stabilities under conditions of 85 °C thermal storage and 45 °C operation.

The impact of thickness-related grain boundary migration on hole concentration and mobility of p-type transparent conducting CuI films.

CuI films present promising optoelectronic properties for transparent conductors. However, the high hole concentration in CuI films hinders the controllable modulation of hole mobility, limiting their application in low-dimensional thin-film transistors. In this study, CuI films were prepared through a Cu film iodination method at room temperature, and a systematic investigation was conducted on the modulation of hole concentration and mobility with varying film thickness. The films exhibited a zinc blende structure (γ-phase) with increasing grain size as the thickness increased. The transmittance and optical bandgap of the films decreased with increasing thickness. The correlation of vacancy concentration with changing film thickness was analyzed through photoluminescence spectroscopy, revealing the influence of grain boundary migration on vacancy formation. The reduction in film thickness diminishes the migration of CuI grain boundaries, consequently reducing the probability of Cu vacancy and I vacancy formation, resulting in diminished hole concentration and enhanced hole mobility and film conductivity. The film with a thickness of 20 nm demonstrated optimal performance, with a transmittance of 90%, hole concentration of 4.09 × 1017 cm-3, hole mobility of 506.50 cm2 V-1 s-1, and conductivity of 33.19 S cm-1. This work deepens the understanding of hole transport such as hole concentration and mobility modulation in CuI films, highlighting the importance of controlling grain boundary migration during the film growth process.

Hole Mobility Enhancement in Benzo[1,2-b:4,5-b']Dithiophene-Based Conjugated Polymer Transistors through Directional Alignment, Perovskite Functionalization and Solid-State Electrolyte Gating.

Tunability in electronic and optical properties has been intensively explored for developing conjugated polymers and their applications in organic and perovskite-based electronics. Particularly, the charge carrier mobility of conjugatedpolymer semiconductors has been deemed to be a vital figure-of-merit for achieving high-performance organic field-effect transistors (OFETs). In this study, the systematic hole carrier mobility improvement of benzo[1,2-b:4,5-b']dithiophene-based conjugated polymer in perovskite-functionalized organic transistors is demonstrated. In conventional OFETs with a poly(methyl methacrylate) (PMMA)gate dielectric, improvements in hole mobility of 0.019cm2V-1s-1 are measured using an off-center spin-coating technique, which exceeds those of on-center counterparts (0.22 ± 0.07 × 10-2cm2V-1s-1). Furthermore, the mobility drastically increases by adopting solid-state electrolyte gating, corresponding to 2.99 ± 1.03cm2V-1s-1 for the control, and the best hole mobility is 8.03cm2V-1s-1 (average ≈ 6.94 ± 0.59cm2V-1s-1) for perovskite-functionalized OFETs with a high current on/off ratio of >106. The achieved device performance would be attributed to the enhanced film crystallinity and charge carrier density in the hybrid perovskite-functionalized organic transistor channel, resulting from the high-capacitance electrolyte dielectric.

Molecular design and synthesis of highly soluble hole transporting materials based on phenylnaphthalene cores for solution-processible OLEDs

Highly soluble small molecules are crucial to realizing large-area solution-processible organic light-emitting diodes with consistent performance. In this study, a series of solution-processable hole transporting materials (HTMs) based on 1,4- and 2,6-phenylnaphthalene (NP) cores were synthesized. The cores had an asymmetric and twisted structure, which enhanced the solubility and thermal stability of the materials. Density functional theory calculations and MD simulations revealed that the 2,6-NP core exhibited a coplanar core structure, leading to a reduced hole reorganization energy and enhanced hole mobility compared to those of the 1,4-NP core. Furthermore, the 2,6-NP-core materials exhibited a higher solubility than the 1,4-NP-core materials. 2,6-NPNP also exhibited the highest solubility, approximately 50 times higher than that of the commercialized HTM N,N′-di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB). Remarkably, when 2,6-NPNP was used as the HTM, the turn-on (Von = 2.54 V) and operating voltages (Vop = 5.67 V @ 1000 nit) of the solution-processed OLED were lower than that of the vacuum-deposited device using NPB as the HTM. Furthermore, the external quantum efficiency, current efficiency, and power efficiency of the former were 1.63 %, 4.49 cd A−1, and 3.78 lm W−1, respectively, which were higher than those of NPB.

Transiently delocalized states enhance hole mobility in organic molecular semiconductors.

Evidence shows that charge carriers in organic semiconductors self-localize because of dynamic disorder. Nevertheless, some organic semiconductors feature reduced mobility at increasing temperature, a hallmark for delocalized band transport. Here we present the temperature-dependent mobility in two record-mobility organic semiconductors: dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]-thiophene (DNTT) and its alkylated derivative, C8-DNTT-C8. By combining terahertz photoconductivity measurements with atomistic non-adiabatic molecular dynamics simulations, we show that while both crystals display a power-law decrease of the mobility (μ) with temperature (T) following μ ∝ T -n, the exponent n differs substantially. Modelling reveals that the differences between the two chemically similar semiconductors can be traced to the delocalization of the different states that are thermally accessible by charge carriers, which in turn depends on their specific electronic band structure. The emerging picture is that of holes surfing on a dynamic manifold of vibrationally dressed extended states with a temperature-dependent mobility that provides a sensitive fingerprint for the underlying density of states.

Thieno[3,2 -b]thiophene-based linear dopant-free hole transport materials for efficient perovskite solar cells

Organic hole transport materials (HTMs) are extensively studied in perovskite solar cells (PSCs). However, due to the inherently low charge carrier mobility, chemical dopants are often required to increase mobility and achieve high power conversion efficiency. Unfortunately, the use of dopants not only brings high costs, but also accelerates the degradation of perovskite, severely reducing the stability of perovskite solar cells. Therefore, developing efficient dopant-free HTMs has become a big challenge. Here, two linear molecules DTTTP-DPA and DTTTP-TPA were designed and synthesized, with diethyl 2,5-bis(thieno [3,2-b]thiophen-2-yl)terephthalate (DTTTP) as the core structure, methoxydiphenylamine/methoxytriphenylamine as the end group, respectively. Compared to diphenylamine, the triphenylamine end group endowed DTTTP-TPA with a longer conjugation length and a lower HOMO level. The longer conjugation is more conducive to charge transporting. While the lower HOMO level due to the weaker electron donating ability of triphenylamine, is potential to achieve a higher open-circuit voltage when used in PSCs. In addition, the carbonyl group in molecular structure could passivate the defect at perovskite/hole transport layer (HTL) interface. As a result, the dopant-free DTTTP-TPA device shows a high photovoltaic performance of 21.62%. At room temperature (30% relative humidity), the initial PCE of the unencapsulated device remains above 93% after 1000 h, showing excellent stability. Our work demonstrates that constructing linear type molecular structure with extended conjugation is an efficient way to enhance hole mobility and is promising to obtain dopant-free HTMs.

Remarkable Enhancement of the Hole Mobility of Novel DA-D'-AD Small Molecules by Thermal Annealing: Effect of the D'-Bridge Block.

Conjugated small molecules are advanced semiconductor materials with attractive physicochemical and optoelectronic properties enabling the development of next-generation electronic devices. The charge carrier mobility of small molecules strongly influences the efficiency of organic and hybrid electronics based on them. Herein, we report the synthesis of four novel small molecules and their investigation with regard to the impact of molecular structure and thermal treatment of films on charge carriers mobility. The benzodithiophene-containing compounds (BDT) were shown to be more promising in terms of tuning the morphology upon thermal treatment. Impressive enhancement of hole mobilities by more than 50 times was found for annealed films based on a compound M4 comprising triisopropylsilyl-functionalized BDT core. The results provide a favorable experience and strategy for the rational design of state-of-the-art organic semiconductor materials (OSMs) and for improving their charge-transport characteristics.

Enhanced charge transport behaviors of single-walled carbon nanotube transistors by phenylphosphonic acid doping

Inkjet printing technology holds promise as a cost-effective method for fabricating large-area electronics, with high compatibility with various substrates. In this paper, we investigate the electrical doping behaviors of p-type transistors based on single-walled carbon nanotubes (SWCNTs), where semiconducting channels and electrodes are patterned using inkjet printing. We demonstrate improved charge transport properties by encapsulating SWCNTs with phenylphosphonic acid (PPA) without annealing. The PPA-coated SWCNT transistors exhibit significantly enhanced hole mobility, reaching approximately 8.25 cm2 V−1 s−1. The presence of the benzene ring in PPA facilitates hole injection and induces a p-doping effect, resulting in a 4.3-fold increase in the on-current level of the transistors.

Carboxylate‐Containing Poly(thiophene vinylene) Derivative with Controlled Molecular Weights for High‐Performance Intrinsically‐Stretchable Organic Solar Cells

AbstractOwing to their simple chemical structures and straightforward synthesis, poly(thiophene vinylene) (PTV) derivatives are promising types of polymer donors for organic solar cells (OSCs). However, the structural rigidity of PTVs results in the formation of films with poor mechanical properties, which limits the application of PTVs in intrinsically stretchable (IS)‐OSCs. Here, new carboxylate‐containing PTVs are developed with tuned molecular weight (MW) (PETTCVT‐X, X = L, M, and H) and realize efficient and mechanically durable IS‐OSCs. The crystallinity of the PTVs increases progressively with increasing MW, leading to enhanced hole mobility and suppressed charge recombination of the OSCs. Moreover, both the mechanical stretchability and electrical properties of the PTVs increase significantly with increasing MW, owing to the formation of tie‐chains that connect the isolated crystalline domains. Consequently, OSCs featuring a PTV with the highest MW (PETTCVT‐H) exhibit the highest power conversion efficiency (PCE, 15.3%) and crack‐onset strain (COS, 7.1%) among the series, compared to lower values for the PETTCVT‐L (PCE = 9.7% and COS = 1.3%) and PETTCVT‐M‐based OSCs (PCE = 12.5% and COS = 3.7%). Therefore, the IS‐OSCs employing PETTCVT‐H present the highest initial PCE (10.1%) and stretchability (strain at PCE80% (retaining 80% of the initial PCE) = 16%).

Enhanced Hole Mobility of p-Type Materials by Molecular Engineering for Efficient Perovskite Solar Cells.

Star-shaped triazatruxene derivative hole-transporting materials (HTMs), namely, 3,8,13-tris(4-(8a,9a-dihydro-9H-carbazol-9-yl)phenyl)-5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (TAT-TY1) and 3,8,13-tris(4-(8a,9a-dihydro-9H-carbazol-9-yl)phenyl)-5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (TAT-TY2), containing electron-rich triazatruxene cores and donor carbazole moieties, were synthesized and successfully used in triple-cation perovskite solar cells. All the HTMs were obtained from relatively inexpensive precursor materials using well-known synthesis procedures and uncomplicated purification steps. All the HTMs, including the 5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole (TAT-H) main core, had suitable highest occupied molecular orbitals (HOMOs) for perovskite (TAT-H: -5.15 eV, TAT-TY1: -5.17 eV, and TAT-TY2: -5.2 eV). Steady-state and time-resolved photoluminescence results revealed that hole transport from the valence band of the perovskite into the HOMO of the new triazatruxene derivatives was more efficient than with TAT-H. Furthermore, the substitution of n-hexylcarbazole and 9-phenylcarbazole in triazatruxene altered the crystalline nature of the main core, resulting in a smooth and pinhole-free thin-film morphology. As a result, the hole mobilities of TAT-TY1 and TAT-TY2 were measured to be one order of magnitude higher than that of TAT-H. Finally, TAT-TY1 and TAT-TY2 achieved power conversion efficiencies of up to 17.5 and 16.3%, respectively, compared to the reference Spiro-OMeTAD. These results demonstrate that the new star-shaped triazatruxene derivative HTMs can be synthesized without using complicated synthesis strategies by controlling the intrinsic morphology of the TAT-H main core.

Helical Polycyclic Heteroaromatic as Hole Transport Material for Perovskite Solar Cell: Remarkable Impact of Alkyl Substitution Position

AbstractPolycyclic aromatic hydrocarbons play a critical role in the development of organic semiconductors. This study unravels the impact of alkyl substitution position on the molecular energy level, glass transition temperature, diffusion of external species, and hole transport of a pyrrole‐rich, helical polycyclic heteroaromatic, that is TBPC. Compared to terminal substitution, internal hexyl substitution results in steric repulsion with TBPC, weakening π─π stacking and therefore improving thin film morphology. Internal substitution also reduces energy disorder, lowers reorganization energy, and increases intermolecular transfer integrals, leading to enhanced hole mobility. Notably, the organic semiconductor with internal hexyl substitution (TBPC‐611) exhibits a higher molecular packing density, resulting in a markedly higher glass transition temperature and slower diffusion of external species. Using TBPC‐611 as the hole transport material, this work successfully fabricates perovskite solar cells with an average power conversion efficiency above 24%, showing good photostability and thermostability. These findings contribute new insights to the development of high‐performance organic semiconductors.

Multidentate Ligand-Passivated CsPbI3 Perovskite Nanocrystals for Stable and Efficient Red-Light-Emitting Diodes.

CsPbI3 nanocrystals (NCs) have become a research hot spot in the field of light-emitting diodes (LEDs). Whereas, the long chain ligands with weak affinity to CsPbI3 NCs have prevented their further development and commercialization. Herein, a novel multidentate short ligand tetramethylthiuram disulfide (TMTD) was employed via a ligand exchange process to enhance hole mobility and decrease trap density of the CsPbI3 NCs film. Therefore, TMTD passivated CsPbI3 NCs LED exhibited 20.65% maximum external quantum efficiency and 3861 cd/m2 maximum luminance. Furthermore, TMTD passivated CsPbI3 NCs LED exhibited good operational stability with a 128 min half-lifetime. This strategy using multidentate short ligand passivation provides an effective way to promote perovskite LED development and commercialization.

Enhanced Hall mobility in graphene-on-electronic-grade diamond

The outstanding electronic properties of graphene make this material a candidate for many applications, for instance, ultra-fast transistors. However, self-heating and especially the detrimental influence of available supporting substrates have impeded progress in this field. In this study, we fabricate graphene-diamond heterostructures by transferring graphene to an ultra-pure single-crystalline diamond substrate. Hall-effect measurements were conducted at 80 to 300 K on graphene Hall bars to investigate the charge transport properties in these devices. Enhanced hole mobility of 2750 cm2 V−1 s−1 could be observed at room-temperature when using diamond with reduced nitrogen (Ns0) impurity concentration. In addition, by electrostatically varying the carrier concentration, an upper limit for mobility is determined in the devices. The results are promising for enabling carbon–carbon (C-C) devices for room-temperature applications.

Extending the π‐Conjugated System in Spiro‐Type Hole Transport Material Enhances the Efficiency and Stability of Perovskite Solar Modules

AbstractHole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl)‐amine‐9,9′‐spirobifluorene (spiro‐OMeTAD, termed “Spiro”) is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro‐type HTM (termed “DP”) by substituting four anisole units on Spiro with 4‐methoxybiphenyl moieties. By extending the π‐conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP‐based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small‐area (0.06 cm2) devices and 21.86 % for modules (designated area of 27.56 cm2), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2. The encapsulated DP‐based devices maintain 95.1 % of the initial performance under ISOS‐L‐1 conditions after 2560 hours and 87 % at the ISOS‐L‐3 conditions over 600 hours.

Extending the π-Conjugated System in Spiro-Type Hole Transport Material Enhances the Efficiency and Stability of Perovskite Solar Modules.

Hole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl)-amine-9,9'-spirobifluorene (spiro-OMeTAD, termed "Spiro") is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro-type HTM (termed "DP") by substituting four anisole units on Spiro with 4-methoxybiphenyl moieties. By extending the π-conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP-based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small-area (0.06 cm2 ) devices and 21.86 % for modules (designated area of 27.56 cm2 ), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2 . The encapsulated DP-based devices maintain 95.1 % of the initial performance under ISOS-L-1 conditions after 2560 hours and 87 % at the ISOS-L-3 conditions over 600 hours.

Efficient non-fullerene organic solar cells employing aqueous solution-processed MoO3 as a hole-transporting layer

Organic solar cell (OSC) has drawn considerable interest in recent decades owing to their advantages of light weight, flexible, large area and potentially low-cost. Employing an appropriate hole-transporting layer (HTL) into an OSC device has been proved as an efficient method to obtain high efficiency OSC due to the enhancement of the hole transporting and extraction of the device. In this work, aqueous solution-processed MoO3 (s-MoO3) thin films were employed as HTLs to construct non-fullerene PM6:Y6 OSCs. The s-MoO3 thin film was prepared by using an aqueous solution process from an isopolymolybdate [NH4]6Mo7O24.4H2O precursor followed by thermal annealing treatment to convert the precursor to MoO3. The s-MoO3 HTL based PM6:Y6 device demonstrates a power conversion efficiency of 15.75%, which is 38% improved than that of the device with thermally evaporated-MoO3 as HTL and 8% improved than that of the device with PEDOT:PSS as HTL. The enhancement of the device performance could be attributed to the enhanced hole mobility and better band matching of the s-MoO3 HTL. Moreover, the s-MoO3 HTL based PM6:Y6 device exhibited higher device stability than those of the reference devices. Our finding indicates that this s-MoO3 film has great potential as efficient HTL for high performance non fullerene OSCs.

Interfacial Interaction Enables Enhanced Mobility in Hybrid Perovskite-Conjugated Polymer Transistors with High-k Fluorinated Polymer Dielectrics.

The charge carrier mobility of organic field-effect transistors (OFETs) has been remarkably improved through several engineering approaches and techniques by targeting pivotal parts. Herein, an ultrathin perovskite channel layer that boosts the field-effect mobility of conjugated polymer OFETs by forming perovskite-conjugated polymer hybrid semiconducting channel is introduced. The optimized lead-iodide-based perovskite-conjugated polymer hybrid channel transistors show enhanced hole mobility of over 4cm2 V-1 s-1 (average=2.10cm2 V-1 s-1 ) with high reproducibility using a benchmark poly(3-hexylthiophene) (P3HT) polymer and employing high-k fluorinated polymer dielectrics. A significant hole carrier mobility enhancement of ≈200-400% in benzo[1,2-b:4,5:b']dithiophene (BDT)-based conjugated polymers is also demonstrated by exploring certain interactive groups with perovskite. This significant enhancement in the transistor performance is attributed to the increased charge carrier density in the hybrid semiconducting channel and the perovskite-polymer interactions. The findings of this paper demonstrate an exceptional engineering approach for carrier mobility enhancement in hybrid perovskite-conjugated-polymer-based electronic devices.

Aqueous-alcohol-processable indolo[3,2-b]indole-based crystalline small molecules for organic field effect transistors with oligo(ethylene glycol) side chains

We address an eco-friendly aqueous process approach to obtain efficient/stable small molecule organic field effect transistors (OFETs). Penta-ethylene glycol (PEG) side chains were introduced at N-positions of the rigid backbone structures of indolo[3,2-b]indole(IDID), thus enabling the formation of PEG-IDIDF. The PEG-IDIDF exhibited remarkable solubility in alcohol (ethanol) solvent. The X-ray diffraction and grazing incidence wide angle X-ray scattering measurements indicate that the suitable addition of a typical cosolvent, water, to ethanol solvent significantly contributes to an enhancement in film crystallinity and molecular stacking orientation features than those of the PEG-IDIDF film processed by using a single solvent. Consequently, the PEG-IDIDF OFETs processed by the ethanol water cosolvent (90:10) ratio yielded the enhanced hole mobility of 4.07 × 10−3 cm2 V−1 s−1 and current on/off ratio of 106, which was one of the highest reliable mobility for small molecules OFETs processed with an alcohol solvent.