Maximum Hole Mobility Research Articles

Substitutional diffusion of Mg into GaN from GaN/Mg mixture

We evaluated Mg-diffusion into GaN from GaN/Mg mixture. The diffusion depth of Mg increased with diffusion temperature from 1100 °C to 1300 °C, whereas the Mg concentration remained constant at 2–3 × 1018 cm−3 independent of temperature. The estimated activation energy for Mg diffusion was 2.8 eV, from which the substitutional diffusion mechanism was predicted. Mg-diffused GaN samples showed p-type conductivity with a maximum hole mobility of 27.7 cm2 V−1 s−1, suggesting that substitutional diffusion contributes to Mg activation. This diffusion technique can be used to easily form p-type GaN and has potential as a p-type selective doping technique.

Two-Dimensional Layered Simple Aliphatic Monoammonium Tin Perovskite Thin Films and Potential Applications in Field-Effect Transistors.

Two-dimensional (2D) layered organic-inorganic perovskites have great potential for fabricating field-effect transistors due to their unique structure that enables the horizontal transport of charge carriers in metal-halide octahedra, resembling the transport behavior in semiconducting channels. Their electronic band structures are mainly dominated by the metal-halide octahedra, which eventually determine the optical and electrical characteristics, whereas organic cations have no direct contributions but would impact the electronic structures via distorting the octahedra. So far, high performance has been achieved in 2D Sn perovskites compared to their Pb counterparts because the intrinsic differences of Sn promote transport properties. The champion hole mobility has been obtained in single-ring aromatic phenylethylammonium tin iodide perovskite [(PEA)2SnI4]. However, simple aliphatic monoammonium tin perovskites and their device applications have rarely been reported. Herein, 2D layered n-butylammonium tin iodide perovskite [(BA)2SnI4] thin films have been synthesized by a spin-coating approach. A structural phase transition occurs at about 225 K in the films, accompanied by the changes in the photoluminescence peak and exciton binding energy. Longitudinal optical (LO) phonons are found to govern the scattering of charge carriers and excitons via the Fröhlich interactions in the temperature range 77-300 K. The first-principles calculations predict that the perovskite has excellent transport characteristics comparable to those of molybdenum disulfide (MoS2) and methylammonium lead iodide perovskite (MAPbI3). The (BA)2SnI4 thin film field-effect transistors constructed on polymer dielectrics with a maximum hole mobility of 0.03 cm2 V-1 s-1 in ambient conditions have been successfully demonstrated for the first time. Our findings not only offer a deep insight into the physical properties of 2D layered aliphatic monoammonium tin perovskite thin films but also provide important experimental and theoretical guidance for their potential applications in lateral-type flexible optoelectronic devices.

Molecular engineering of several butterfly-shaped hole transport materials containing dibenzo[b,d]thiophene core for perovskite photovoltaics

Several butterfly-shaped materials composed of dibenzo[b,d]thiophene (DBT) and dibenzo-dithiophene (DBT5) cores were designed as hole transporting materials (HTMs) and their properties were studied by density functional theory (DFT) computations for usage in mesoscopic n-i-p perovskite solar cells (PSCs). To choose suitable HTMs, it was displayed that both of lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energies of molecules were located higher than those of CH3NH3PbI3 (MAPbI3) perovskite as they were able to transfer holes from the MAPbI3 toward Ag cathode. Negative solvation energy (ΔEsolvation) values for all HTMs (within the range of − 5.185 to − 18.140 kcal/mol) revealed their high solubility and stability within CH2Cl2 solvent. The DBT5-COMe demonstrated the lowest values of band gap (Eg = 3.544) and hardness (η = 1.772 eV) (the greatest chemical activity) and DBT5-CF3 displayed the biggest η = 1.953 eV (maximum stability) that were predominantly valuable for effective HTMs. All HTMs presented appropriately high LHEs from 0.8793 to 0.9406. In addition, the DBT5 and DBT5-SH depicted the lowest exciton binding energy (Eb) values of 0.881 and 0.880 eV which confirmed they could produce satisfactory results for the PSCs assembled using these materials. The DBT5-SH and DBT5-H had maximum hole mobility (μh) values of 6.031 × 10–2 and 1.140 × 10–2 which were greater than those measured for the reference DBT5 molecule (μh = 3.984 × 10–4 cm2/V/s) and about 10 and 100 times superior to the calculated and experimental μh values for well-known Spiro-OMeTAD. The DBT5-COOH illustrated the biggest open circuit voltage (VOC), fill factor (FF) and power conversion efficiency (PCE) values of 1.166 eV, 0.896 and 23.707%, respectively, establishing it could be as the best HTM candidate for high performance PSCs.

Polyurethane-Based Stretchable Semiconductor Nanofilms with High Intrinsic Recovery Similar to Conventional Elastomers.

Polymer semiconductors with large elastic recovery (ER) under high strain in thin film state are highly desirable for stretchable electronics. Here we report a type of stretchable semiconductor PU(DPP)x, by copolymerization of oligodiketopyrrolopyrrole-based conjugated block and hydrogenated polybutadiene flexible block via urethane linkage for intermolecular hydrogen bonding. By regulating block ratio, PU(DPP)35 with 35 wt % conjugated block exhibits high intrinsic ER > 80% under 175% strain (ε) in pseudo free-standing thin film state, comparable with commercial elastomers, and crack onset strain (COS) > 300% along with maximum hole mobility of 0.19 cm2 V-1 s-1 in organic thin film transistors to bring it to the best performing block copolymer-type stretchable semiconductors. Enhanced mobility is achieved using PU(DPP)35 as the binder for conjugated polymer PDPPT3. The 25 wt %-PDPPT3 blend displays mobility up to 1.28 cm2 V-1 s-1 along with COS ∼120%, and 10 wt %-PDPPT3 blend exhibits ER of 78% at ε = 150%, COS of ∼230%, modulus of 36.5 MPa, maximum mobility of 0.62 cm2 V-1 s-1 and no obvious degradation of mobility at ε = 150% after 100 cycles of strain. Moreover, the structural similarity enables the blend film uniform and stable microstructure against mechanical and thermal deformation. Notably, PU(DPP)35 and the blend are characterized by high mechanical performance similar to that of commercial elastomers in thin film state, and demonstrate their potential for high performance stretchable electronics.

Side-chain engineering by thymine groups enables hydrogen bond in P-type donor-acceptor polymers with enhanced optoelectronic properties

Realizing ordered structures at the molecular level is a key approach to increase the charge mobility of organic semiconductors. However, the typical solution-based methods employed for the processing make the achievement of well-organized organic nanostructures difficult with the favored formation of disordered assemblies. To realize well-ordered thin films, one needs to design conjugated materials with the ability of self-assembling. In this work, two alternating donor-acceptor copolymers based on the carbazole and diketopyrrolopyrrole (DPP) units, namely P1 and P2, are successfully synthesized. Compared to P1, the polymer P2 contains an extra thymine group at the end of the alkyl chain, through which the hydrogen bonding (CO⋯NH) can be formed between the amide (NH) and carbonyl units (CO), as verified by the fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) study. The electrochemical analysis shows that the hydrogen bonding association influences the carbazole donor ability, resulting in a higher HOMO energy level of P2 compared to P1. In addition, the as-formed hydrogen bonds promote the assembling of the molecules into highly ordered structures by enabling strong aggregation as well as a narrow distance between adjacent molecules with long-range ordering packing and large nanocrystalline grains. As a result, the intermolecular charge transfer is enhanced. Consequently, the organic field-effect transistors (OFETs) constructed with P2 as the semiconductor layer present a p-type behavior with maximum hole mobility up to 1.32 cm2 V−1 s−1 upon annealing, which is almost 5 times higher than that of the pristine P2 (0.26 cm2 V−1 s−1), while the hole mobility of the annealed P1 is only 0.23 cm2 V−1 s−1. Our results indicate that the alkyl chain engineering, with the introduction of a thymine group into the donor units of the polymer, is responsible for the formation of hydrogen-bonded superstructures. This is a facile approach to enhance the optoelectronic properties of organic semiconductors.

Substituent effects on the luminescence and charge transport properties of novel bis-lactam-based molecules

A series of bis-lactam-based molecules were synthesized and applied in organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). Among the derivatives, 1,5-dioctyl-3,7-bis(9-phenyl-9H-carbazol-2-yl)-1,5-naphthyridine-2,6-dione (NTD-pCz) exhibited the highest maximum hole mobility of 0.11 cm2 V−1 s−1, with on–off current ratios (Ion/Ioff) of >105 in OFETs, which was attributed to NTD-pCz exhibiting the lowest reorganization energy, extended π-conjugation with a relatively small dihedral angle between the NTD core and the side group, and the strongest intermolecular interaction in the thin-film state. In addition, NTD-pCz exhibited the highest maximum external quantum efficiency of 3.56%, with a current efficiency of 9.95 cd A−1, when incorporated into nondoped OLEDs, which is ascribed to its excellent solid-state photoluminescence quantum yield of 83%. These results reveal the potential of NTD-based molecules for use in efficient next-generation multifunctional optoelectronic devices.

Accurate parametrization revealing an extremely low disorder in polymer field-effect transistors

In this paper, a robust self-consistent parameter extraction method is applied to high-performance p-type printed polymer field-effect transistors. Simultaneous extraction of contact resistance and intrinsic channel mobility with their full gate-voltage dependence is achieved through an analytically reinforced transmission-line method. The proposed method yields a minimum width-normalized contact resistance of 12 kΩ cm and a maximum hole mobility of 1.9 cm2 V−1 s−1. Moreover, the gate-voltage-dependent mobility is interpreted in the framework of trap-and-release transport through double-exponential density of states, unveiling a disorder energy near the transport orbital as low as 29 meV.

Valence band structure of biaxial strained Germanium for hole transport calculation

A comprehensive study of hole mobility in Germanium material dependence on strained substrate orientations and carrier transport directions was performed in this paper. The heavy hole, light hole, and spin–orbit bands are included in the calculation of valence band structure. The biaxial strain induced valence band edge energy splitting and effective mass change were evaluated as well as their impacts on the hole mobility in Germanium were analysed. The results show that the optimum strained substrate orientation and carrier transport direction configuration are biaxial compressive strained on the (110) oriented substrate and in-plane as a hole transport direction, the configuration of which has the maximum hole mobility under the same strained level in comparison with others. The reason for high hole mobility is also explored. The current research is helpful to design the high performances p-channel MOSFETs in the strained Germanium system. The hole mobility of Germanium versus strain level under different biaxial strained substrate and transport directions configurations

Enhancement in Charge Carrier Mobility by Using Furan as Spacer in Thieno[3,2-b]Pyrrole and Alkylated-Diketopyrrolopyrrole Based Conjugated Copolymers

The structural alteration of semiconducting polymer backbones can improve the optoelectronic properties of organic semiconductors and enhance field-effect mobilities. In our efforts towards improving the performance of organic field-effect transistors (OFETs), we are reporting a donor–acceptor polymer containing thieno[3,2-b]pyrrole (TP) donor and a furan-flanked diketopyrrolopyrrole (DPP) electron acceptor, which yielded an asymmetric poly(methylthienopyrrolo)furanyl)diketopyrrolopyrrol) P(FDPP-TP) organic semiconducting polymer. The introduction of a furan spacer improved thermally induced crystallinity and molecular packing, as confirmed by grazing incidence X-ray diffraction (XRD) and tapping-mode atomic force microscopy (TMAFM). The tested OFET devices gave maximum hole mobility of 0.42 cm2 V−1 s−1 with threshold voltages around 0 V for bottom-gate bottom-contact device configuration.

Annealing effect of absorber layer on SnS/CdS heterojunction band alignments

The effect of annealing on the physical properties of an SnS thin film and also on SnS/CdS heterojunction band alignment was studied. Vacuum annealing has greatly improved the crystalline quality of SnS and an average grain size of 1.6 μm was achieved. Sulfur-rich secondary phases observed on the surface of as-grown SnS thin film were eliminated after vacuum annealing, resulting in a decrease of the resistivity and an increase of the carrier concentration of the film. A maximum hole mobility of 17 cm2 V−1 s−1 was obtained for SnS thin films annealed at 400 °C. A transition of SnS/CdS heterojunction from “spike” type to “cliff” type was observed when the vacuum annealed SnS thin film was post-air-annealed at 200 and 250 °C. The band alignment of SnS/CdS heterojunction could be adjustable between “spike” type to “cliff” type via vacuum annealing followed by post-air-annealing.

Normally-off hydrogen-terminated diamond field effect transistor with a bilayer dielectric of Er2O3/Al2O3

A normally-off hydrogen-terminated diamond field effect transistor with an Er2O3/Al2O3 bilayer dielectric was fabricated. Dielectric materials Er2O3 and Al2O3 were deposited on H-diamond surface using radio frequency sputtering and atomic layer deposition, respectively. The threshold voltage of the device was −0.49 V at VDS of −20 V, which indicated a normally off characteristic, that could be attributed to the low work function of Er2O3 and the polar character of amorphous Er2O3. The maximum drain-source current for the hydrogen-terminated diamond field effect transistor with 6 μm gate length was −16.1 mA/mm and the sheet carrier density integrated was 1.08 × 1013 cm−2. The maximum effective hole mobility was 110.47 cm2/V·s and the interfacial trapped charge density was 3.16 × 1012 eV−1 cm−2. This bilayer dielectric of Er2O3/Al2O3 provides an alternative plan for the fabrication of normally-off diamond device.

Brewers’ spent grain (BSG)-based green dielectric materials for low-voltage operating solution-processed organic field-effect transistors

A brewers’ spent grain (BSG) based dielectric material was used in organic field-effect transistors (OFETs). The fabricated devices showed a maximum hole mobility of 2.30 cm2 V−1 s−1.

Incorporation of Selenopheno[3,2-b]pyrrole into Benzothiadiazole-Based Small Molecules for Organic Field-Effect Transistors

Incorporating selenophene into organic semiconductors has recently shown promising results in both organic solar cells (OSCs) and organic field-effect transistors (OFETs). In most studies, replacing thiophene with selenophene has improved the performance in OSCs and OFETs. However, some other reports do not show the same trend. Therefore, the structure–property relationship of selenophene-containing semiconducting materials is still to be investigated and understood. On the other hand, reports have shown that thiophene flanked benzothiadiazole- and thieno[3,2-b]pyrrole-based donor–acceptor–donor molecular architecture gave a banana-shaped small organic conjugated molecule with moderate OFETs performance. To understand the structure–property relationship and influence on OFETs performance, by replacing thiophene with selenophene in chalcogenopheno[3,2-b]pyrrole, we report a nonconventional fused ring system, ester-monocapped selenopheno[3,2-b]pyrrole, which was coupled with chalcogenophene spacer flanked benzothiadiazole to yield two curved small organic conjugated molecules, diethyl 2,2′-(5,5′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(thiophene-5,2-diyl))bis(4-dodecyl-4H-selenopheno[3,2-b]pyrrole-5-carboxylate (BT-2T-2SeP) and diethyl 2,2′-(benzo[c][1,2,5]thiadiazole-4,7-diylbis(selenophene-5,2-diyl))bis(4-dodecyl-4H-selenopheno[3,2-b]pyrrole-5-carboxylate (BT-2Se-2SeP). This is the first report of selenopheno[3,2-b]pyrrole incorporated in donor–acceptor small conjugated organic molecules for OFETs applications. BT-2T-2SeP and BT-2Se-2SeP exhibited comparable maximum hole mobilities of 8.82 × 10–3 cm2 V–1 s–1 and 1.44 × 10–2 cm2 V–1 s–1, respectively. Furthermore, these molecules exhibited lower threshold voltages between 0-(−5) V and high on–off current ratios of 104 and ∼105, respectively, for BT-2T-2SeP and BT-2Se-2SeP.

Effect of Chlorine or Ester Incorporation on Diketopyrrolopyrrole -Based Polymeric Semiconductors

Organic photovoltaic materials incorporating either chlorine atoms or ester groups have been studied as replacement strategy for fluorinated compounds. However, the characteristics of such materials when used in organic field-effect transistors (OFETs) remain unclear. The present work synthesized three polymers via the copolymerization of diketopyrrolopyrrole (DPP) with monothiophene units having no substituents or incorporating either chlorine atoms or ester groups. All three materials were found to have similar photophysical and electrochemical properties even though their repeating units had different substituents. The maximum hole mobility values for the polymer specimens were determined to be 0.37 cm 2 V −1 s −1 . The introduction of chlorine into the DPP-based polymer generated an amorphous semiconductor material that makes it a very promising candidate for commercial OFETs since its properties are independent of fabrication conditions. The new polymeric semiconductors demonstrated herein suggest the viability of such materials with regard to incorporation in organic field-effect transistors. •Both ester groups and chlorine atoms were successfully introduced into DPP-based polymers. •Chlorination and esterification applied to polymeric OFET materials •The introduction of chlorine into the DPP-based polymer generated an amorphous semiconductor material.

Preferential vertically oriented nanopillar perovskite induced by poly(9-vinylcarbazole) field-effect transistor

Organic-inorganic hybrid perovskite could potentially be used to create field-effect transistors (FETs) with high field-effect mobility. However, the energy level mismatch at the deep valence band maximum perovskite-contact junction and morphological defects greatly limit the charge transport in the thin film. In this work, we demonstrated charge injection can be improved by introducing Nafion as a surface modifier on top of the Indium tin oxide. Incorporating poly (9-vinylcarbazole) PVK into a quasi-one-dimensional precursor solution induced preferential vertically orientated nanopillars as revealed by synchrotron-based two-dimensional grazing incident X-ray diffraction. This simultaneously reduced the grain boundaries and improved pin-hole free films. As a result, maximum hole mobility of 0.012 cm2/Vs was achieved with a reduction in the hysteresis. Our work demonstrated the dependence of FETs performance on the injection barrier and perovskite nanopillar microstructure.

Exploring the hole mobility of oligothiophene based donors with different spatial symmetry and conjugation length of backbone: A theoretical insight

AbstractNovel oligothiophene based donors have been synthesized and modified. However, how molecular modifications influence their molecular stacking and charge carrier mobility is not clear. In this work, we have selected two high‐performance oligothiophene based donors DRCN5T and DRCN6T to understand why the hole mobility of DRCN5T/PC71BM is much faster than that of DRCN6T/PC71BM in the experiment (Journal of the American Chemical Society, 2015). The computed data indicate that the maximum hole mobility of DRCN5T is about 20 times faster than that of DRCN6T. Moreover, DRCN5T has faster hole mobility than DRCN6T in almost every similar configuration. These mobility differences can be explained with the different positions and sparsity of side alkyl chains on the backbones. The work here gives a deep insight into the hole mobility in oligothiophene based OSCs and thereby may provide a guideline for future oligothiophene‐based donor material design and morphology control.

Crystal Engineering of Angular-Shaped Heteroarenes Based on Cyclopenta[b]thiopyran for Controlling the Charge Carrier Mobility.

Cyclopenta[b]thiopyran, isomeric to benzo[b]thiophene while isoelectronic to azulene, is involved as a building block to construct soluble organic semiconductors for field-effect transistors. Two series of angular-shaped heteroarenes based on cyclopenta[b]thiopyran, that is, Cn-SS (n = 4, 6, 8, 10) with different linear alkyl groups and C8-SS-Clm (m = 2, 3, 4) with chlorides substituted at different positions, have been straightforward synthesized. The obtained seven S-heteroarenes exhibit intriguing and similar photophysical and electrochemical properties, such as near-infrared absorption and high-energy levels of the highest occupied molecular orbitals. Nevertheless, the S-heteroarenes with identical π-conjugated skeletons demonstrate completely different molecular packing structures, which is proofed to be the key determinate factor for the charge carrier mobilities. Upon the engineering of the pendant alkyl lengths, the highest hole mobility in the Cn-SS series is achieved for C8-SS (1.1 cm2 V-1 s-1) with moderate alkyl length. The further incorporation of chlorides on C8-SS results in the shortened intermolecular H···S contacts and the interplane distances. Most interestingly, when chlorine-containing chloroform and chlorobenzene are used as crystallization solvents, single crystals of C8-SS-Clm with different packing structures are produced owing to the intermolecular interactions among the solute and solvent molecules. Upon further engineering of the chlorination position and the crystallization solvent, the maximum hole mobility in the ambient air improves to 2.7 cm2 V-1 s-1 for C8-SS-Cl2 crystallized from chlorobenzene, suggesting that the introduction of the accessible chlorides is a feasible pathway to engineering the crystal structures and controlling the charge transport characteristics.

One-dimensional van der Waals stacked p-type crystal Ta2Pt3Se8 for nanoscale electronics.

Recently, ternary transition metal chalcogenides Ta2X3Se8 (X = Pd or Pt) have attracted great interest as a class of emerging one-dimensional (1D) van der Waals (vdW) materials. In particular, Ta2Pd3Se8 has been actively studied owing to its excellent charge transport properties as an n-type semiconductor and ultralong ballistic phonon transport properties. Compared to subsequent studies on the Pd-containing material, Ta2Pt3Se8, another member of this class of materials has been considerably less explored despite its promising electrical properties as a p-type semiconductor. Herein, we demonstrate the electrical properties of Ta2Pt3Se8 as a promising channel material for nanoelectronic applications. High-quality bulk Ta2Pt3Se8 single crystals were successfully synthesized by a one-step vapor transport reaction. Scanning Kelvin probe microscopy measurements were used to investigate the surface potential difference and work function of the Ta2Pt3Se8 nanoribbons of various thicknesses. Field-effect transistors fabricated on exfoliated Ta2Pt3Se8 nanoribbons exhibited moderate p-type transport properties with a maximum hole mobility of 5 cm2 V-1 s-1 and an Ion/Ioff ratio of >104. Furthermore, the charge transport mechanism of Ta2Pt3Se8 was analyzed by temperature-dependent transport measurements in the temperature range from 90 to 320 K. To include Ta2Pt3Se8 in a building block for modern 1D electronics, we demonstrate p-n junction characteristics using the electron beam doping method.

Picene and PTCDI based solution processable ambipolar OFETs

Facile and efficient solution-processed bottom gate top contact organic field-effect transistor was fabricated by employing the active layer of picene (donor, D) and N,N′-di(dodecyl)-perylene-3,4,9,10-tetracarboxylic diimide (acceptor, A). Balanced hole (0.12 cm2/Vs) and electron (0.10 cm2/Vs) mobility with Ion/off of 104 ratio were obtained for 1:1 ratio of D/A blend. On increasing the ratio of either D or A, the charge carrier mobility and Ion/off ratio improved than that of the pristine molecules. Maximum hole (µmax,h) and electron mobilities (µmax,e) were achieved up to 0.44 cm2/Vs for 3:1 and 0.25 cm2/Vs for 1:3, (D/A) respectively. This improvement is due to the donor phase function as the trap center for minority holes and decreased trap density of the dielectric layer, and vice versa. High ionization potential (− 5.71 eV) of 3:1 and lower electron affinity of (− 3.09 eV) of 1:3 supports the fine tuning of frontier molecular orbitals in the blend. The additional peak formed for the blends at high negative potential of − 1.3 V in cyclic voltammetry supports the molecular level electronic interactions of D and A. Thermal studies supported the high thermal stability of D/A blends and SEM analysis of thin films indicated their efficient molecular packing. Quasi-π–π stacking owing to the large π conjugated plane and the crystallinity of the films are well proved by GIXRD. DFT calculations also supported the electronic distribution of the molecules. The electron density of states (DOS) of pristine D and A molecules specifies the non-negligible interaction coupling among the molecules. This D/A pair has unlimited prospective for plentiful electronic applications in non-volatile memory devices, inverters and logic circuits.

Two‐Step Synthesis of Large‐Area 2D Bi2S3 Nanosheets Featuring High In‐Plane Anisotropy

Abstract2D materials with high in‐plane anisotropy are rapidly emerging as a tantalizing class of nanomaterials with promising applications in nanoelectronics and optoelectronics since they provide an additional degree of freedom that can be exploited in device design. The large‐area synthesis of such materials remains however challenging since the anisotropic crystal structure renders identifying a suitable growth substrate to be difficult, while the nanosheets are usually too fragile for the exfoliation and transfer of macroscopic sheets. This work reports the scalable synthesis of highly crystalline, large‐area 2D Bi2S3 nanosheets using a novel liquid‐metal‐based synthesis approach. Ultrathin bismuth oxide sheets are exfoliated from molten bismuth followed by tube furnace sulfurization. The strategy effectively separates the formation of layered structures from the process of anisotropic crystallization, overcoming the shortcomings of established techniques. The synthesized nanosheets feature a highly anisotropic orthorhombic crystal structure with intraplane van der Waals gaps and a direct bandgap of ≈2.3 eV. The nanosheets are found to be highly photoconductive with a photoresponsivity of 8 A W−1. Bi2S3 channel‐based field effect transistors feature a maximum hole mobility of 28 cm2 V−1 s−1, highlighting the excellent electronic properties of the isolated nanosheets.