Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Solution‐processed small‐molecule bulk heterojunction (BHJ) ambipolar organic thin‐film transistors are fabricated based on a combination of [2‐phenylbenzo[d,d']thieno[3,2‐b;4,5‐b']dithiophene (P‐BTDT) : 2‐(4‐n‐octylphenyl)benzo[d,d ']thieno[3,2‐b;4,5‐b']dithiophene (OP‐BTDT)] and C₆₀. Treating high electrical performance vacuum‐deposited P‐BTDT organic semiconductors with a newly developed solution‐processed organic semiconductor material, OP‐BTDT, in an optimized ratio yields a solution‐processed p‐channel organic semiconductor blend with carrier mobility as high as 0.65 cm² V^?1 s^?1. An optimized blending of P‐BTDT:OP‐BTDT with the n‐channel semiconductor, C₆₀, results in a BHJ ambipolar transistor with balanced carrier mobilities for holes and electrons of 0.03 and 0.02 cm² V^?1 s^?1, respectively. Furthermore, a complementary‐like inverter composed of two ambipolar thin‐film transistors is demonstrated, which achieves a gain of 115.     

High‐Performance n‐Channel Thin‐Film Field‐Effect Transistors Based on a Nanowire‐Forming Polymer

A new electrontransport polymer, poly{[N,N′‐dioctylperylene‐3,4,9,10‐bis(dicarboximide)‐1,7(6)‐diyl]‐alt‐[(2,5‐bis(2‐ethyl‐hexyl)‐1,4‐phenylene)bis(ethyn‐2,1‐diyl]} (PDIC8‐EB), is synthesized. In chloroform, the polymer undergoes self‐assembly, forming a nanowire suspension. The nanowire's optical and electrochemical properties, morphological structure, and field‐effect transistor (FET) characteristics are investigated. Thin films fabricated from a PDIC8‐EB nanowire suspension are composed of ordered nanowires and ordered and amorphous non‐nanowire phases, whereas films prepared from a homogeneous PDIC8‐EB solution consist of only the ordered and amorphous non‐nanowire phases. X‐ray scattering experiments suggest that in both nanowires and ordered phases, the PDIC8 units are laterally stacked in an edge‐on manner with respect to the film plane, with full interdigitation of the octyl chains, and with the polymer backbones preferentially oriented within the film plane. The ordering and orientations are significantly enhanced through thermal annealing at 200 °C under inert conditions. The polymer film with high degree of structural ordering and strong orientation yields a high electron mobility (0.10 ± 0.05 cm² V^?1 s^?1), with a high on/off ratio (3.7 × 10⁶), a low threshold voltage (8 V), and negligible hysteresis (0.5 V). This study demonstrates that the polymer in the nanowire suspension provides a suitable material for fabricating the active layers of high‐performance n‐channel FET devices via a solution coating process.     

Variable Temperature Mobility Analysis of n‐Channel,p‐Channel,and Ambipolar Organic Field‐Effect Transistors

The temperature dependence of field‐effect transistor (FET) mobility is analyzed for a series of n‐channel, p‐channel, and ambipolar organic semiconductor‐based FETs selected for varied semiconductor structural and device characteristics. The materials (and dominant carrier type) studied are 5,5′′′‐bis(perfluorophenacyl)‐2,2′:5′,2″:5″,2′′′‐quaterthiophene ( 1 , n‐channel), 5,5′′′‐bis(perfluorohexyl carbonyl)‐2,2′:5′,2″:5″,2′′′‐quaterthiophene ( 2 , n‐channel), pentacene ( 3 , p‐channel); 5,5′′′‐bis(hexylcarbonyl)‐2,2′:5′,2″:5″,2′′′‐quaterthiophene ( 4 , ambipolar), 5,5′′′‐bis‐(phenacyl)‐2,2′: 5′,2″:5″,2′′′‐quaterthiophene ( 5 , p‐channel), 2,7‐bis((5‐perfluorophenacyl)thiophen‐2‐yl)‐9,10‐phenanthrenequinone ( 6 , n‐channel), and poly(N‐(2‐octyldodecyl)‐2,2′‐bithiophene‐3,3′‐dicarboximide) ( 7 , n‐channel). Fits of the effective field‐effect mobility (µ_eff) data assuming a discrete trap energy within a multiple trapping and release (MTR) model reveal low activation energies (E_As) for high‐mobility semiconductors 1 – 3 of 21, 22, and 30 meV, respectively. Higher E_A values of 40–70 meV are exhibited by 4 – 7 ‐derived FETs having lower mobilities (µ_eff). Analysis of these data reveals little correlation between the conduction state energy level and E_A, while there is an inverse relationship between E_A and µ_eff. The first variable‐temperature study of an ambipolar organic FET reveals that although n‐channel behavior exhibits E_A = 27 meV, the p‐channel regime exhibits significantly more trapping with E_A = 250 meV. Interestingly, calculated free carrier mobilities (µ₀) are in the range of ～0.2–0.8 cm² V^?1 s^?1 in this materials set, largely independent of µ_eff. This indicates that in the absence of charge traps, the inherent magnitude of carrier mobility is comparable for each of these materials. Finally, the effect of temperature on threshold voltage (V_T) reveals two distinct trapping regimes, with the change in trapped charge exhibiting a striking correlation with room temperature µ_eff. The observation that E_A is independent of conduction state energy, and that changes in trapped charge with temperature correlate with room temperature µ_eff, support the applicability of trap‐limited mobility models such as a MTR mechanism to this materials set.     

High‐Mobility and Low Turn‐On Voltage n‐Channel OTFTs Based on a Solution‐Processable Derivative of Naphthalene Bisimide

In organic electronics solution‐processable n‐channel field‐effect transistors (FETs) matching the parameters of the best p‐channel FETs are needed. Progress toward the fabrication of such devices is strongly impeded by a limited number of suitable organic semiconductors as well as by the lack of processing techniques that enable strict control of the supramolecular organization in the deposited layer. Here, the use of N,N′‐bis(4‐n‐butylphenyl)‐1,4,5,8‐naphthalenetetracarboxylic‐1,4:5,8‐bisimide (NBI‐4‐n‐BuPh) for fabrication of n‐channel FETs is described. The unidirectionally oriented crystalline layers of NBI‐4‐n‐BuPh are obtained by the zone‐casting method under ambient conditions. Due to the bottom‐contact, top‐gate configuration used, the gate dielectric, Parylene C, also acts as a protective layer. This, together with a sufficiently low LUMO level of NBI‐4‐n‐BuPh allows the fabrication and operation of these novel n‐channel transistors under ambient conditions. The high order of the NBI‐4‐n‐BuPh molecules in the zone‐cast layer and high purity of the gate dielectric yield good performance of the transistors.     

Molecule Charge Transfer Doping for p‐Channel Solution‐Processed Copper Oxide Transistors

The doping of semiconductors plays a critical role in improving the performance of modern electronic devices by precisely controlling the charge carrier density. However, the absence of a stable doping method for p‐type oxide semiconductors has severely restricted the development of metal oxide‐based transparent p–n junctions and complementary circuits. Here, an efficient and stable doping process for p‐type oxide semiconductors by using molecule charge transfer doping with tetrafluoro‐tetracyanoquinodimethane (F₄TCNQ) is reported. The selections of a suitable dopant and geometry play a crucial role in the charge‐transfer doping effect. The insertion of a F₄TCNQ thin dopant film (2–7 nm) between a Au source‐drain electrode and solution‐processed p‐type copper oxide (Cu_xO) film in bottom‐gate top‐contact thin‐film transistors (TFTs) provides a mobility enhancement of over 20‐fold with the desired threshold voltage adjustment. By combining doped p‐type Cu_xO and n‐type indium gallium zinc oxide TFTs, a solution‐processed transparent complementary metal‐oxide semiconductor inverter is demonstrated with a high gain voltage of 50. This novel p‐doping method is expected to accelerate the development of high‐performance and reliable p‐channel oxide transistors and has the potential for widespread applications.     

High‐Mobility n‐Type Organic Transistors Based on a Crystallized Diketopyrrolopyrrole Derivative

A new high‐performing small molecule n‐channel semiconductor based on diketopyrrolopyrrole (DPP), 2,2′‐(5,5′‐(2,5‐bis(2‐ethylhexyl)‐3,6‐dioxo‐2,3,5,6‐tetrahydropyrrolo[3,4‐c]pyrrole‐1,4‐diyl)bis(thiophene‐5,2‐diyl))bis(methan‐1‐yl‐1‐ylidene)dimalononitrile (DPP‐T‐DCV), is successfully synthesized. The frontier molecular orbitals in this designed structure are elaborately tuned by introducing a strong electron‐accepting functionality (dicyanovinyl). The well‐defined lamellar structures of the crystals display a uniform terrace step height corresponding to a molecular monolayer in the solid‐state. As a result of this tuning and the remarkable crystallinity derived from the conformational planarity, organic field‐effect transistors (OFETs) based on dense‐packed solution‐processed single‐crystals of DPP‐T‐DCV exhibit an electron mobility (μ_e) up to 0.96 cm² V^?1 s^?1, one of the highest values yet obtained for DPP derivative‐based n‐channel OFETs. Polycrystalline OFETs show promise (with an μ_e up to 0.64 cm² V^?1 s^?1) for practical utility in organic device applications.     

Self‐Assembled Nanowires of Organic n‐Type Semiconductor for Nonvolatile Transistor Memory Devices

Organic nonvolatile transistor‐type memory (ONVM) devices are developed using self‐assembled nanowires of n‐type semiconductor, N,N′‐bis(2‐phenylethyl)‐perylene‐3,4:9,10‐tetracarboxylic diimide (BPE‐PTCDI). The effects of nanowire dimension and silane surface treatment on the memory characteristics are explored. The diameter of the nanowires is reduced by increasing the non‐solvent methanol composition, which led to the enhanced crystallinity and high field‐effect mobility. The BPE‐PTCDI nanowires with small diameters induce high electrical fields and result in a large memory window (the shifting of the threshold voltage, ΔV_th). The ΔV_th value of BPE‐PTCDI nanowire based ONVM device on the bare substrate can reach 51 V, which is significantly larger than that of thin film. The memory window is further enhanced to 78 V with the on/off ratio of 2.1 × 10⁴ and the long retention time (10⁴ s), using a hydrophobic surface (such as trichloro(phenyl)silane‐treated surface). The above results demonstrate that the n‐type semiconducting nanowires have potential applications in high performance non‐volatile transistor memory devices.     

Solution‐Processed Ambipolar Field‐Effect Transistor Based on Diketopyrrolopyrrole Functionalized with Benzothiadiazole

Ambipolar charge transport in a solution‐processed small molecule 4,7‐bis{2‐[2,5‐bis(2‐ethylhexyl)‐3‐(5‐hexyl‐2,2′:5′,2″‐terthiophene‐5″‐yl)‐pyrrolo[3,4‐c]pyrrolo‐1,4‐dione‐6‐yl]‐thiophene‐5‐yl}‐2,1,3‐benzothiadiazole (BTDPP2) transistor has been investigated and shows a balanced field‐effect mobility of electrons and holes of up to ～10^?2 cm² V^?1 s^?1. Using low‐work‐function top electrodes such as Ba, the electron injection barrier is largely reduced. The observed ambipolar transport can be enhanced over one order of magnitude compared to devices using Al or Au electrodes. The field‐effect mobility increases upon thermal annealing at 150 °C due to the formation of large crystalline domains, as shown by atomic force microscopy and X‐ray diffraction. Organic inverter circuits based on BTDPP2 ambipolar transistors display a gain of over 25.     

Gate Capacitance‐Dependent Field‐Effect Mobility in Solution‐Processed Oxide Semiconductor Thin‐Film Transistors

Solution‐processed oxide semiconductors (OSs) used as channel layer have been presented as a solution to the demand for flexible, cheap, and transparent thin‐film transistors (TFTs). In order to produce high‐performance and long‐sustainable portable devices with the solution‐processed OS TFTs, the low‐operational voltage driving current is a key issue. Experimentally, increasing the gate‐insulator capacitances by high‐k dielectrics in the OS TFTs has significantly improved the field‐effect mobility of the OS TFTs. But, methodical examinations of how the field‐effect mobility depends on gate capacitance have not been presented yet. Here, a systematic analysis of the field‐effect mobility on the gate capacitances in the solution‐processed OS TFTs is presented, where the multiple‐trapping‐and‐release and hopping percolation mechanism are used to describe the electrical conductivity of the nanocrystalline and amorphous OSs, respectively. An intuitive single‐piece expression showing how the field‐effect mobility depends on gate capacitance is developed based on the aforementioned mechanisms. The field‐effect mobility, depending on the gate capacitances, of the fabricated ZnO and ZnSnO TFTs clearly follows the theoretical prediction. In addition, the way in which the gate insulator properties (e.g., gate capacitance or dielectric constant) affect the field‐effect mobility maximum in the nanocrystalline ZnO and amorphous ZnSnO TFTs are investigated.     

Solution‐Processable Dithienothiophenoquinoid (DTTQ) Structures for Ambient‐Stable n‐Channel Organic Field Effect Transistors

A series of dialkylated dithienothiophenoquinoids ( DTTQ s), end‐functionalized with dicyanomethylene units and substituted with different alkyl chains, are synthesized and characterized. Facile one‐pot synthesis of the dialkylated DTT core is achieved, which enables the efficient realization of DTTQ s as n‐type active semiconductors for solution‐processable organic field effect transistors (OFETs). The molecular structure of hexyl substituted DTTQ‐6 is determined via single‐crystal X‐ray diffraction, revealing DTTQ is a very planar core. The DTTQ cores form a “zig‐zag” linking layer and the layers stack in a “face‐to‐face” arrangement. The very planar core structure, short core stacking distance (3.30 Å), short intermolecular S? N distance (2.84 Å), and very low lying lowest unoccupied molecular orbital energy level of ?4.2 eV suggest that DTTQ s should be excellent electron transport candidates. The physical and electrochemical properties as well as OFETs performance and thin film morphologies of these new DTTQ s are systematically studied. Using a solution‐shearing method, DTTQ‐11 exhibits n‐channel transport with the highest mobility of up to 0.45 cm² V^?1 s^?1 and a current ON/OFF ratio (I _ON/I _OFF) greater than 10⁵. As such, DTTQ‐11 has the highest electron mobility of any DTT‐based small molecule semiconductors yet discovered combined with excellent ambient stability. Within this family, carrier mobility magnitudes are correlated with the alkyl chain length of the side chain substituents of DTTQ s.     

n‐Channel,Ambipolar, and p‐Channel Organic Heterojunction Transistors Fabricated with Various Film Morphologies

The relationship between the performance characteristics of organic field‐effect transistors (OFETs) with 2,5‐bis(4‐biphenylyl)bithiophene/copper hexadecafluorophthalocyanine (BP2T/F₁₆CuPc) heterojunctions and the thickness of the BP2T bottom layer is investigated. Three operating modes (n‐channel, ambipolar, and p‐channel) are obtained by varying the thickness of the organic semiconductor layer. The changes in operating mode are attributable to the morphology of the film and the heterojunction effect, which also leads to an evolution of the field‐effect mobility with increasing film thickness. In BP2T/F₁₆CuPc heterojunctions the mobile charge carriers accumulate at both sides of the heterojunction interface, with an accumulation layer thickness of ca. 10 nm. High field‐effect mobility values can be achieved in continuous and flat films that exhibit the heterojunction effect.     

Enhanced Performance of Fullerene n‐Channel Field‐Effect Transistors with Titanium Sub‐Oxide Injection Layer

Enhanced performance of n‐channel organic field‐effect transistors (OFETs) is demonstrated by introducing a titanium sub‐oxide (TiO_x) injection layer. The n‐channel OFETs utilize [6,6]‐phenyl‐C₆₁ butyric acid methyl ester (PC₆₁BM) or [6,6]‐phenyl‐C₇₁ butyric acid methyl ester (PC₇₁BM) as the semiconductor in the channel. With the TiO_x injection layer, the electron mobilities of PC₆₁BM and PC₇₁BM FET using Al as source/drain electrodes are comparable to those obtained from OFETs using Ca as the source/drain electrodes. Direct measurement of contact resistance (R_c) shows significantly decreased R_c values for FETs with the TiO_x layer. Ultraviolet photoelectron spectroscopy (UPS) studies demonstrate that the TiO_x layer reduces the electron injection barrier because of the relatively strong interfacial dipole of TiO_x. In addition to functioning as an electron injection layer that eliminates the contact resistance, the TiO_x layer acts as a passivation layer that prevents penetration of O₂ and H₂O; devices with the TiO_x injection layer exhibit a significant improvement in lifetime when exposed to air.     

High‐Mobility Naphthalene Diimide and Selenophene‐Vinylene‐Selenophene‐Based Conjugated Polymer: n‐Channel Organic Field‐Effect Transistors and Structure–Property Relationship

Interdependence of chemical structure, thin‐film morphology, and transport properties is a key, yet often elusive aspect characterizing the design and development of high‐mobility, solution‐processed polymers for large‐area and flexible electronics applications. There is a specific need to achieve >1 cm² V^?1 s^?1 field‐effect mobilities (μ) at low processing temperatures in combination with environmental stability, especially in the case of electron‐transporting polymers, which are still lagging behind hole transporting materials. Here, the synthesis of a naphthalene‐diimide based donor–acceptor copolymer characterized by a selenophene vinylene selenophene donor moiety is reported. Optimized field‐effect transistors show maximum μ of 2.4 cm² V^?1 s^?1 and promising ambient stability. A very marked film structural evolution is revealed with increasing annealing temperature, with evidence of a remarkable 3D crystallinity above 180 °C. Conversely, transport properties are found to be substantially optimized at 150 °C, with limited gain at higher temperature. This discrepancy is rationalized by the presence of a surface‐segregated prevalently edge‐on packed polymer phase, dominating the device accumulated channel. This study therefore serves the purpose of presenting a promising, high‐electron‐mobility copolymer that is processable at relatively low temperatures, and of clearly highlighting the necessity of specifically investigating channel morphology in assessing the structure–property nexus in semiconducting polymer thin films.     

High‐Mobility ZnO Thin Film Transistors Based on Solution‐processed Hafnium Oxide Gate Dielectrics

The properties of metal oxides with high dielectric constant (k) are being extensively studied for use as gate dielectric alternatives to silicon dioxide (SiO₂). Despite their attractive properties, these high‐k dielectrics are usually manufactured using costly vacuum‐based techniques. In that respect, recent research has been focused on the development of alternative deposition methods based on solution‐processable metal oxides. Here, the application of the spray pyrolysis (SP) technique for processing high‐quality hafnium oxide (HfO₂) gate dielectrics and their implementation in thin film transistors employing spray‐coated zinc oxide (ZnO) semiconducting channels are reported. The films are studied by means of admittance spectroscopy, atomic force microscopy, X‐ray diffraction, UV–Visible absorption spectroscopy, FTIR, spectroscopic ellipsometry, and field‐effect measurements. Analyses reveal polycrystalline HfO₂ layers of monoclinic structure that exhibit wide band gap (≈5.7 eV), low roughness (≈0.8 nm), high dielectric constant (k ≈ 18.8), and high breakdown voltage (≈2.7 MV/cm). Thin film transistors based on HfO₂/ZnO stacks exhibit excellent electron transport characteristics with low operating voltages (≈6 V), high on/off current modulation ratio (～10⁷) and electron mobility in excess of 40 cm² V^?1 s^?1.     

Controlling Ambipolar Charge Transport in Isoindigo‐Based Conjugated Polymers by Altering Fluorine Substitution Position for High‐Performance Organic Field‐Effect Transistors

A molecular design strategy to achieve highly balanced ambipolar charge transport for donor–acceptor (D–A) isoindigo (IIG)‐based copolymer through systematic selection of fluorination positions is reported. To study fluorine substitution site effects on electronic and structural properties, two fluorinated IIG‐based copolymers (PIIG‐iFT2 and PIIG‐oFT2) are synthesized, which contain two fluorine atoms at the bithiophene (T2) inner and outer site and compare them with a nonfluorinated copolymer of IIG and T2 (PIIG‐T2) as the reference polymer. Fluorination at the outer site of T2 in PIIG‐oFT2 polymer effectively lowers molecular energy levels and increases molecular planarity more than fluorination at the T2 inner site. PIIG‐oFT2 organic field‐effect transistors show highly balanced ambipolar mobility, hole mobility (μ_h)/electron mobility (μ_e) = 1 by increasing electron mobility, whereas PIIG‐T2 (μ_h/μ_e = 9.0) and PIIG‐iFT2 (μ_h/μ_e = 2.4) exhibit unbalanced ambipolar transport. The ambipolar complementary‐like inverter is also demonstrated by simple one‐time coating of PIIG‐oFT2 with gain = 21.     

Thionation Enhances the Electron Mobility of Perylene Diimide for High Performance n‐Channel Organic Field Effect Transistors

Perylene diimides (PDIs) are one of the most widely studied n‐type materials, showing great promise as electron acceptors in organic photovoltaic devices and as electron transport materials in n‐channel organic field effect transistors. Amongst the well‐established chemical modification strategies for increasing the electron mobility of PDI, substitution of the imide oxygen atoms with sulfur, known as thionation, has remained largely unexplored. In this work, it is demonstrated that thionation is a highly effective means of enhancing the electron mobility of a bis‐N‐alkylated PDI derivative. Successive oxygen–sulfur substitution increases the electron mobility such that the fully thionated derivative ( S4 ) has an average mobility of 0.16 cm² V^?1 s^?1. This is two orders of magnitude larger than the nonthionated parent compound ( P ), and is achieved by solution deposition and without thermal or solvent vapor annealing. A combination of atomic force microscopy and 2D wide angle X‐ray scattering experiments, together with theoretical modeling of charge transport efficiency, is used to explain the strong positive correlation observed between electron mobility and degree of thionation. This work establishes thionation as a highly effective means of enhancing the electron mobility of PDI, and provides motivation for the development of thionated PDI derivatives for organic electronics applications.     

Solution‐Processed Zinc Oxide as High‐Performance Air‐Stable Electron Injector in Organic Ambipolar Light‐Emitting Field‐Effect Transistors

Electron injection from the source–drain electrodes limits the performance of many n‐type organic field‐effect transistors (OFETs), particularly those based on organic semiconductors with electron affinities less than 3.5 eV. Here, it is shown that modification of gold source–drain electrodes with an overlying solution‐deposited, patterned layer of an n‐type metal oxide such as zinc oxide (ZnO) provides an efficient electron‐injecting contact, which avoids the use of unstable low‐work‐function metals and is compatible with high‐resolution patterning techniques such as photolithography. Ambipolar light‐emitting field‐effect transistors (LEFETs) based on green‐light‐emitting poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole) (F8BT) and blue‐light‐emitting poly(9,9‐dioctylfluorene) (F8) with electron‐injecting gold/ZnO and hole‐injecting gold electrodes show significantly lower electron threshold voltages and several orders of magnitude higher ambipolar currents, and hence light emission intensities, than devices with bare gold electrodes. Moreover, different solution‐deposited metal oxide injection layers are compared. By spin‐coating ZnO from a low‐temperature precursor, processing temperatures could be reduced to 150 °C. Ultraviolet photoemission spectroscopy (UPS) shows that the improvement in transistor performance is due to reduction of the electron injection barrier at the interface between the organic semiconductor and ZnO/Au compared to bare gold electrodes.     

High‐Mobility Air‐Stable Solution‐Shear‐Processed n‐Channel Organic Transistors Based on Core‐Chlorinated Naphthalene Diimides

High charge carrier mobility solution‐processed n‐channel organic thin‐film transistors (OTFTs) based on core‐chlorinated naphthalene tetracarboxylic diimides (NDIs) with fluoroalkyl chains are demonstrated. These OTFTs were prepared through a solution shearing method. Core‐chlorination of NDIs not only increases the electron mobilities of OTFTs, but also enhances their air stability, since the chlorination in the NDI core lowers the lowest unoccupied molecular orbital (LUMO) levels. The air‐stability of dichlorinated NDI was better than that of the tetrachlorinated NDIs, presumably due to the fact that dichlorinated NDIs have a denser packing of the fluoroalkyl chains and less grain boundaries on the surface, reducing the invasion pathway of ambient oxygen and moisture. The devices of dichlorinated NDIs exhibit good OTFT performance, even after storage in air for one and a half months. Charge transport anisotropy is observed from the dichlorinated NDI. A dichlorinated NDI with ?CH₂C₃F₇ side chains reveals high mobilities of up to 0.22 and 0.57 cm² V^?1 s^?1 in parallel and perpendicular direction, respectively, with regard to the shearing direction. This mobility anisotropy is related to the grain morphology. In addition, we find that the solution‐shearing deposition affects the molecular orientation in the crystalline thin films and lowers the d(001)‐spacing (the out‐of‐plane interlayer spacing), compared to the vapor‐deposited thin films. Core‐chlorinated NDI derivatives are found to be highly suitable for n‐channel active materials in low‐cost solution‐processed organic electronics.