Enhanced Charge Transport Research Articles

Chemical insights into electrophilic fluorination of SnO2for photoelectrochemical applications

A novel method for fluorination of SnO2is developed that passivates oxygen defects and increases its electrical conductivity drastically, leading to enhanced charge transport in photoelectrochemical applications.

Interface engineering of moisture-induced ionic albumen dielectric layers through self-crosslinking of cysteine amino acids for low voltage, high-performance organic field-effect transistors.

The interface roughness between the semiconducting and dielectric layers of organic field-effect transistors (OFETs) plays a crucial role in the charge transport mechanism through the device. Here we report the interface engineering of a moisture induced ionic albumen material through systematic control of the temperature-dependent self-crosslinking of cysteine amino acids in the dielectric layer. The evolution of the surface morphologies of albumen and pentacene semiconducting films has been studied to achieve a smooth interface for enhanced charge transport. A structural transition of pentacene films from crystalline dendrite to amorphous was induced by the higher surface roughness of the albumen film. The devices showed a high transconductance of 11.68 μS at a lower threshold voltage of -0.9 V.

Enhancement of charge transport in interconnected lignin-derived carbon fibrous network for flexible battery-supercapacitor hybrid device

Self-supporting and flexible carbon fibrous mats are promising electrode materials for wearable devices. The contact resistance between adjacent fibers is still a limit for further improvement of energy storage performance. Herein, an activated interconnected lignin-derived carbon fibrous network (AILCFN) is fabricated by electrospinning followed by heat treatment. The unique interconnected structure between fibers in AILCFN is designed by controlling the ratio of soft Kraft lignin fractions with different thermal mobility. While the interconnected fibers are benefited for the electron transport and conductive property of the carbon networks, the high specific surface area is synergistically conduced to the direct channels for the fast ion transfer. The as-prepared AILCFN-3 exhibits an excellent specific capacitance and a high rate capability (69% from the current density from 1 to 20 mA cm−2). Further, AILCFN-3 can act as the scaffold to support the electrodeposited Ni-Co-S nanosheets. The AILCFN/Ni-Co-S composite electrode displays a high specific capacity of 1140.0 C g−1 at a current density of 10 A g−1. The assembled AILCFN/Ni-Co-S//AILCFN-3 BSH exhibits a high energy density of 30.8 Wh kg−1 with a power density of 0.8 kW kg−1 and demonstrates both excellent cyclability and flexibility, attributed to the high effective specific surface area and advantageous interconnected structure. The self-powered system assembled onto a lab coat can continuously power for the electronic watch under sunlight illumination and dark environment, demonstrating the promising potential of AILCFN in future wearable electronics. This work represents a “waste into wealth” direction of conversion strategy from biomass waste lignin to value-added energy storage materials, which conversely turns different thermal property of lignin fractions to good account, and breaks through the application limits caused by the heterogeneity.

N, S-GQDs and Au nanoparticles co-modified ultrathin Bi2MoO6 nanosheet with enhanced charge transport dynamics for full-spectrum-light-driven molecular oxygen activation

It is a great challenge to achieve ultrafast charge transfer and simultaneously strengthen light adsorption for full-spectrum-light-activated photocatalysis. In this work, N and S co-doped graphene quantum dots (N, S-GQDs) and Au nanoparticles are successfully co-modified on atomic ultrathin Bi2MoO6 nanosheet, and the prepared hybrid material displays exceptional performance in charge carrier transfer and light harvest. The obtained hybrid material possesses excellent photocatalytic activity in molecular oxygen activation for oxytetracycline (OTC) degradation with 3.69-fold higher reaction rate than pristine Bi2MoO6 under visible light irradiation. In addition, it also possesses near-infrared-light-driven catalytic activity, about 24.47% of OTC can be degraded under near-infrared light irradiation. Moreover, the hybrid material displays outstanding catalytic performance for actual wastewater treatment, and it also possesses high photostability. The mechanism exploration reveals that the boosted photocatalytic performance is originated from three aspects. The up-conversion photoluminescence feature of N, S-GQDs broadens photoresponse range, and the light nanoantenna and SPR effect of Au nanoparticle enhance light absorption intensity. Meanwhile, both N, S-GQDs and Au nanoparticles accelerate charge carrier transfer, the surface charge transfer efficiency of pristine Bi2MoO6 and hybrid material are calculated to be 33.74% and 53.04%, respectively. Furthermore, the possible photodegradation pathway of OTC is also inquired according to liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS). This work provides inspiration to rationally design high-performance full-spectrum-light-driven catalysts in molecular oxygen activation for environmental modification.

Water-Surface Drag Coating: A New Route Toward High-Quality Conjugated Small-Molecule Thin Films with Enhanced Charge Transport Properties.

Electronic properties of organic semiconductor (OSC) thin films are largely determined by their morphologies and crystallinities. However, solution-processed conjugated small-molecule OSC thin films usually exhibit abundant grain boundaries and impure grain orientations because of complex fluid dynamics during solution coating. Here, a novel methodology, water-surface drag coating, is demonstrated to fabricate high-quality OSC thin films with greatly enhanced charge transport properties. This method utilizes the water surface to alter the evaporation dynamics of solution to enlarge the grain size, and a unique drag-coating process to achieve the unidirectional growth of organic crystals. Using 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (Dif-TES-ADT) as an example, thin films with millimeter-sized single-crystal domains and pure crystallographic orientations are achieved, revealing a significant enhancement (4.7 times) of carrier mobility. More importantly, the resulting film can be directly transferred onto any desired flexible substrates, and flexible transistors based on the Dif-TES-ADT thin films show a mobility as high as 16.1 cm2 V-1 s-1 , which represents the highest mobility value for the flexible transistors reported thus far. The method is general for the growth of various high-quality OSC thin films, thus opening up opportunities for high-performance organic flexible electronics.

Cocrystallization-Promoted Charge Mobility in All-Conjugated Diblock Copolymers for High-Performance Field-Effect Transistors.

The cocrystallization method that combines various constituents into cocrystals yields the newly formed materials with significantly enhanced charge transport properties. However, this strategy has not been greatly utilized in all-conjugated block copolymers (BCPs). Herein, we scrutinize the relationship between cocrystals and charge mobilities in all-conjugated BCPs (i.e., poly(3-butylthiophene)-block-poly(3-hexylthiophene); denoted P3BT-b-P3HT) by tuning their molecular weights and thermal annealing process. All the rod-rod BCPs form cocrystals with high charge mobilities than P3BT and P3HT homopolymers and P3BT/P3HT blend, imparting the cocrystal-facilitated charge transport because of the synergy of two conjugated components. Upon 150 °C treatment, their crystallinities increase and their charge mobilities at 15k, 18k, and 28k increase slightly. In contrast, P3BT-b-P3HT-12k shows decreased charge mobilities. It is due to the preferential increase of crystal size and order through the π-π stacking direction in the former while through the alkyl stacking direction in the latter. Intriguingly, when these P3BT-b-P3HT cocrystals experience two-step thermal treatment, P3BT-b-P3HT-12k retains its cocrystalline structure, while microphase separation of P3BT and P3HT occurs in P3BT-b-P3HT-15k, 18k, and 28k with different degrees. All P3BT-b-P3HT BCPs exhibit decreased charge mobilities. This study demonstrates the cocrystallization-promoted charge mobility in all-conjugated BCPs, which may facilitate their application in a wide range of optoelectronic devices.

Random copolymerization of polythiophene for simultaneous enhancement of in‐plane and out‐of‐plane charge transport for organic transistors and perovskite solar cells

High-performance conjugated polymers for electronic applications can be developed by modulating an appropriate chemical structure that optimizes their crystal characteristics and charge-transport behavior. Herein, we demonstrated the simultaneous enhancement of the in-plane and out-of-plane charge transport of polythiophenes by random polymerization. We synthesized a polythiophene polymer by varying the ratio of two different dialkyl-substituted bi-thiophene and triethylene glycol-substituted mono-thiophene units; this polymer exhibited weakened orientation preferences of polymer crystallite films, a denser packing, and a more homogeneous surface morphology in comparison with its homopolymer analogue. Furthermore, this optimized random polymer afforded an enhanced in-plane mobility of 7.72 cm2 V−1 second−1, measured by field-effect transistor, and out-of-plane mobility of 8.86 × 10−4 cm2 V−1 second−1, measured by space-charge-limited-current device. These are respectively 2.4 times and 10 times higher than the mobilities of the homopolymer (field-effect mobility = 3.25 cm2 V−1 second−1 and space-charge-limited-current mobility = 8.73 × 10−5 cm2 V−1 second−1). The enhanced charge transport in out-of-plane direction was also confirmed by fabricating perovskite solar cells using optimized polythiophene as a hole-transporting material, which exhibited a higher efficiency of nearly 16.2% than the device with homopolymer analogue (12.0%).

Tuning the morphologic and electronic structures of self-assembled NiSe/Ni3Se2 heterostructures with vanadium doping toward efficient electrocatalytic hydrogen production

Tailoring the nonprecious nickel selenide heterogeneous electrocatalysts with controllable morphology and electronic structures is of prime importance to enhance the catalytic efficiency for hydrogen production evolution (HER). Here, we report the solvothermal in-situ synthesis of vanadium-incorporated NiSe/Ni3Se2 heterogeneous structures (VNS) on porous nickel foam, which function as an efficient electrode toward HER, together with superior catalytic activity and durability. Impressively, the self-assembled VNS electrode delivers the current densities of 100, 500 and 1000 mA cm−2 at quite low overpotentials of 175, 275 and 348 mV with 85% iR-compensation toward HER in 1.0 M KOH solution. Mott-Schottky analysis indicates that the vanadium doping alters the flat band potential of VNS, and in turn affects the electrons migration behavior at electrode and electrolyte interface. Benefiting from its dramatically increased catalytic active sites exposure, enhanced charge transport capability, and optimized electronic structure, the hierarchical VNS heterostructures exhibit an impressive HER electrocatalytic performance in alkaline media. More broadly, this research provides a promising strategy for design and exploitation of more advanced electrocatalysts for large-scale hydrogen production on selenides using heteroatom vanadium incorporation.

High-performance bulky crystalline copper bismuthate photocathode for enhanced solar water splitting

Copper bismuthate (CuBi2O4, CBO) has attracted attention as a promising photocathode material for photoelectrochemical (PEC) water-splitting because of its small bandgap (1.6–1.8 eV), high internal photovoltage, and moderate stability in aqueous media. Herein, we report a novel solution synthesis method to fabricate bulky crystalline CBO photocathodes via an evaporation decomposition controlled process. The CBO photocathode synthesized under optimal conditions exhibited a uniform, dense film with intimate substrate contact and large-grains, allowing an enhanced charge transport and photocurrent stability in comparison to porous CBO counterparts. Consequently, the dense CBO achieved a photocurrent density of − 1.16 mA/cm2 at 0.4 V versus the reversible hydrogen electrode (RHE) without a scavenger addition under simulated sunlight irradiation (AM 1.5 G, 100 mW/cm2). Significantly, the coupling of the CBO with a cupric oxide (CuO) underlayer and a Pt electrocatalyst increased the photocurrent density further to − 2.8 and − 3.5 mA/cm2 at 0.4 V versus RHE, respectively, which is the highest value to date among all reported CBO based photocathodes.

Efficient and High-Luminance Perovskite Light-Emitting Diodes Based on CsPbBr3 Nanocrystals Synthesized from a Dual-Purpose Organic Lead Source.

Rational engineering of the surface properties of perovskite nanocrystals (PeNCs) is critical to obtain light emitters with simultaneous high photoluminescence efficiency and excellent charge transport properties for light-emitting diodes (LEDs). However, the commonly used lead halide sources make it hard to rationally optimize the surface compositions of the PeNCs. In addition, previously developed ligand engineering strategies for conventional inorganic nanocrystals easily deteriorate surface properties of the PeNCs, bringing additional difficulties in optimizing their optoelectronic properties. In this work, a novel strategy of employing a dual-purpose organic lead source for the synthesis of highly luminescent PeNCs with enhanced charge transport property is developed. Lead naphthenate (Pb(NA)2 ), of which the metal ions work as lead sources while the naphthenate can function as the surface ligands afterward, is explored and the obtained products under different synthesis conditions are comprehensively investigated. Monodispersed cesium lead bromide (CsPbBr3 ) with controllable size and excellent optical properties, showing superior photoluminescence quantum yields up to 80%, is obtained. Based on the simultaneously enhanced electrical properties of the Pb(NA)2 -derived PeNCs, the resultant LEDs demonstrate a high peak external quantum efficiency of 8.44% and a superior maximum luminance of 31759cd cm-2 .

Enhanced Charge Transport in Ca2MnO4-Layered Perovskites by Point Defect Engineering.

Coupling between thermal and charge transport in crystalline materials has always been one of the greatest challenges in understanding the underlying physics of thermoelectric materials. In this sense, CaO(CaMnO3)m Ruddlesden–Popper layered perovskites, comprising m perovskite subcells separated by CaO planes, exhibit intriguing thermal and electronic transport properties that can be tuned by altering their crystal periodicities. Applying the well-established phonon glass electron crystal (PGEC) concept enables us to increase the transparency of these CaO planes to electron transport at the same time while preserving their opacity to phonon transport. First-principles calculations indicate that the total local potential at CaO planes, where Y substitutes for Ca, is lower by ca. 50% compared to La substitution. Measurements of the electrical conductivity and Seebeck coefficients for Ca2–xRxMnO4 (R = La or Y; x = 0.01, 0.05, 0.1, and 0.15) bulk materials in the range of 300–1000 K confirm that compounds doped with Y exhibit higher electrical conductivity values than their La-doped counterparts. We attribute this to lower polaron hopping energy values (up to 23%) evaluated using the small polaron hopping model. This study introduces an original way to employ the PGEC approach for thermoelectric oxides.

Effects of post-deposition CdCl2 annealing on electronic properties of CdTe solar cells

The effects of post-deposition CdCl2 annealing temperature on the electronic properties of CdTe solar cells were investigated. CdTe devices incorporate Mg doped ZnO as a buffer layer and selenization using a CdSe interlayer for reducing the buffer/absorber interface recombination and increasing solar energy absorption respectively. The post-deposition CdCl2 annealing treatments were done under separate, inert atmospheres of nitrogen and helium across the temperature range 380–430 °C. Electrical characterization of devices is carried out including temperature dependent current-voltage characteristics, admittance spectroscopy, and Shockley-Read-Hall recombination analysis. The best improvements in device efficiency are obtained upon annealing at temperature 410 °C. This anneal correlated with reduced back contact barrier in CdTe and reduced grain-boundary barrier height which is beneficial for enhanced charge transport.

Rational Mutual Interactions in Ternary Systems Enable High‐Performance Organic Solar Cells

AbstractTernary organic solar cells (TOSCs) offer a facile and efficient approach to increase the power conversion efficiencies (PCEs). However, the critical roles that guest components play in complicated ternary systems remain poorly understood. Herein, two acceptors named LA1 and LA9 with differing crystallinity are investigated. The overly crystalline LA9 induces large self‐aggregates in PM6:LA9 binary system, resulting in a lower PCE (13.12%) compared to PM6:LA1 device (13.89%). Encouragingly, both acceptors are verified as efficient guest candidates into the host binary PM6:NCBDT‐4Cl (PCE = 13.48%) and afford markedly improved PCEs up to 15.39% and 15.75% in LA1 and LA9 ternary devices, respectively. Interestingly, the higher crystallinity LA9 reveals smaller interaction energies with both the host acceptor and donor PM6. Compared to LA1, the appropriate mutual interactions in the LA9 ternary system not only induces the orderly crystallinity of PM6 but also better compatibility with the host acceptor, generating further optimized molecular orientations and ternary morphology. Therefore, enhanced charge transport and minimized recombination loss are detected in LA9 ternary devices, affording the most competitive performance among Y6‐sbsent TOSCs. This work suggests that complicated intermolecular interactions should be seriously considered when fabricating state‐of‐the‐art multiple components OSCs.

Electrical Signature of Ultrasound-Induced Anisotropic Self-Assembly of Poly(3-Hexylthiophene) (P3HT) during Channel Formation

We probed ultrasound irradiation-induced structural ordering of poly(3-hexylthiophene) (P3HT) chains during solidification of a sonicated P3HT solution by monitoring the temporal evolution of the electrical and spectroscopic signals. We observed a peak source-drain current in the test devices during the electrical channel formation, followed by a significant decrease, which has not been observed in the pristine P3HT solution as the solvent evaporates. Through P3HT concentration-dependent gated-sheet conductance and in-situ Raman spectroscopy measurements during channel formation, we found that the competition between aggregation of the disentangled P3HT chains in solution by sonication and the concentration-dependent chain interactions with solvent evaporation led to a distinct electrical signature in the channel formation of the sonicated P3HT film compared to that of the pristine P3HT. The finding provides insights into new opportunities through optimization between the thermodynamic and kinetic considerations in designing pre-deposition treatments for enhanced charge transport.

(Invited) Highly Reliable Metal Oxide Thin Film Transistors for Flexible Devices

Amorphous oxide semiconductors (AOS), such as amorphous InZnO (IZO), have been widely explored as channel material for thin-film transistors (TFTs) due to its high mobility (μ) and excellent uniformity.Its solution processability allows for application to cheap and flexible electronics. To achieve cheaper manufacturing cost and large-area production, successful integration of solution-based layers is necessary. In fact, other popular solution-based conductive films, such as carbon nanotubes and polymeric materials have been previously used as electrodes. However, their conductivity is generally lower and their integration requires complex processes. Meanwhile, AOS show promising optoeletronic properties as well as good contact with oxide channels. In this work, solution-based IZO semiconductor was functionalized for electrode applications using photo-assisted treatments, namely UV and excimer laser irradiation, and was employed in an all-solution oxide TFT fabrication.IZO functionalization was achieved through either UV (λ=254 nm) irradiation for 15 to 60 mins or with additional excimer laser (λ=248 nm) irradiation in vacuum, air, or N2 at a fluence from 100 to 140 mJ cm-2. The results of X-ray photoelectron spectroscopy O 1s analysis suggests oxygen vacancy generation which effectively increases the carrier concentration in the irradiated IZO film. Moreover, IZO was crystallized from the amorphous as-deposited film after irradiation as obtained from X-ray diffraction and scanning transmission electron microscopy analyses. The laser-induced heating likely caused the IZO crystallization which provided the enhanced charge transport in the oxide film. Finally, the metal-oxide functionalization was employed in an all-solution processed oxide TFT fabrication using IZO for the channel and the electrodes, and fluorinated polysiloxane for the gate insulator. The self-aligned TFT structure that was employed, enabled the selective functionalization of the IZO gate, source, and drain electrodes. The metal oxide functionalization using UV and excimer laser irradiation yielded oxide TFTs with excellent transfer characteristics and good stability even after three months of storage in air. The all-solution processed fabrication demonstrated in this work is relevant for high throughput fabrication such as roll-to-roll processing.

Importance of Optimal Crystallinity and Hole Mobility of BDT‐Based Polymer Donor for Simultaneous Enhancements of Voc, Jsc, and FF in Efficient Nonfullerene Organic Solar Cells

AbstractIn this work, a new series of polymer donors consisting of thienothiophene π‐bridged N‐octylthieno[3,4‐c]pyrrole‐4,6‐dione (8ttTPD) and benzo[1,2‐b:4,5‐b']dithiophene (BDT) units for producing highly efficient organic solar cells (OSCs) paired with a Y6 acceptor is developed. The incorporation of the highly planar 8ttTPD unit enhances crystalline properties as well as hole mobilities of the BDT‐based polymers that typically have amorphous features. Further, the 2D side chains with halogen atoms (fluorine and chlorine) are designed as another handle to control the crystallinity and energy levels of the BDT‐based polymer donors: PBDT‐X (X = H, F, or Cl). Synergistic effects of incorporated 8ttTPD unit and the halogenated 2D side chain generate significantly enhanced charge transport and recombination properties of the OSCs, which is mainly attributed to optimized crystallinity and hole mobility of the polymer donors. Therefore, the PBDT‐Cl:Y6‐based OSCs exhibit the highest power conversion efficiency (PCE) of 15.63% with simultaneous improvements of open‐circuit voltage, short‐circuit current density, and fill factor, which outperforms the PCEs of PBDT‐H:Y6 (11.84%) and PBDT‐F:Y6 (14.86%).

Numerical Development of Concentric Cylinder‐Shaped Dual‐Functional Catalyst Structure for Enhanced Charge Transport in Polymer Electrolyte Fuel Cells

AbstractDual‐functional catalyst bilayers of vertical concentric cylinders are proposed and numerically developed using a stochastic modeling approach to improve catalyst utilization for advanced fuel cell applications. A cylindrically bilayered catalyst structure wherein the ion transport materials are confined by concentric outer carbon shells is adopted to increase the number of interconnected electron and ion transport paths. For reliable statistical analysis, each data point is extracted from a set of 25 catalyst layer models to achieve a 95% confidence level. The nanoscale morphologies of the ionomers, including interconnected ion transport networks, surface coverage, and electrochemically active surface areas, are quantitatively evaluated. The statistical investigations reveal that the bilayered cylindrical catalyst structures provide more uniform and improved transport paths for ions and reactants when compared with established catalyst layers. Specifically, the additional ion transport channels in the core of the concentric vertical cylinder enhance catalyst utilization under insufficient ionomer conditions. Furthermore, the bilayered catalyst structures yield remarkably enlarged electrochemically active surface areas, hence facilitating more efficient electron, ion, and reactant transfers to improve catalyst utilization.

Synthesis of porous Ag2S−NiCo2S4 hollow architecture as effective electrode material with high capacitive performances

Fabrication of highly reactive and cost-effective electrode materials is a key to efficient functioning of green energy technologies. Decorating redox-active metal sulfides with conductive dopants is one of the most effective approaches to enhance electric conductivity and consequently boost capacitive properties. Herein, hierarchically hollow Ag2S−NiCo2S4 architectures are designed with an enhanced conductivity by a simple solvothermal approach. With the favorable porous characteristics and composition, the optimized Ag2S−NiCo2S4-5 electrode exhibits higher specific capacitance (276.5 mAh g−1 at a current density of 1 A g−1), a good rate performance (56.3% capacity retention at 50 A g−1), and an improved cycling stability (92.4% retention after 2000 cycles). This finding originates from the enhanced charge transportation ability within the hierarchical structure, abundant electroactive sites, and low contact resistance. In addition, a battery supercapacitor device constructed with the Ag2S−NiCo2S4-5 as a positive electrode displays a maximum energy density of 63.3Wh kg−1 at an energy density of 821.8 W kg−1 with an excellent cycling stability (89.4% capacity retention after 10 000 cycles). Therefore, the present work puts forward new possibility to develop composite electrodes for energy storage battery-supercapacitor.

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

AbstractOrganic–inorganic hybrid quasi‐2D perovskites have shown excellent stability for perovskite solar cells (PSCs), while the poor charge transport in quasi‐2D perovskites significantly undermines their power conversion efficiency (PCE). Here, studies on water‐controlled crystal growth of quasi‐2D perovskites are presented to achieve high‐efficiency solar cells. It is demonstrated that the (BA)2MA4Pb5I16‐based PSCs (n = 5) processed with water‐containing precursors display an increased short‐circuit current density (Jsc) of 19.01 mA cm−2 and PCE over 15%. The enhanced performance is attributed to synergetic growths of the 3D and 2D phase components aided by the formed hydration (MAI∙H2O), leading to modulations on the crystal orientation and phase distribution of various n‐value components, which facilitate interphase charge transfer and charge sweepout throughout the device. The water‐assisted crystallization is further applied to triple cation‐based (BA)2(MA0.8FA0.15Cs0.05)4Pb5I16 quasi‐2D perovskites, which generate a remarkable PCE of 18.04%. Despite the presence of water in the precursors, the devices exhibit a satisfactory thermal stability with the PCE degradation <15% under continuous thermal aging at 60 °C for over 500 h.

Simple hole-transporting materials containing twin-carbazole moiety and unconjugated flexible linker for efficient and stable perovskite solar cells

Three twin-carbazole-based hole-transporting materials (HTMs) bearing an unconjugated flexible linker and four peripheral diphenylamine groups with different methoxy positions (pp-, pm-, and po-) are first synthesized (GJ-pp, GJ-pm, and GJ-po) and successfully employed in perovskite solar cells (PSCs). The HTMs were obtained from simple synthetic steps and facile purification techniques. The thermal stability, optical and electrochemical properties, density functional theory calculations, hole-transporting properties, X-ray diffraction, hole transfer dynamics, hydrophobic properties, surface morphology, and photovoltaic performances were measured and discussed. Device performance depends on the methoxy group positions. GJ-pp shows the best power conversion efficiency (17.23%) among the three twin-carbazole-based HTMs, and slightly lower than that of the spiro-OMeTAD-based devices (17.96%). However, the GJ-pp-based devices show outstanding thermal stability compared with the spiro-OMeTAD-based ones. Laboratory synthetic cost of GJ-pp is merely 29.0% of the purchasable spiro-OMeTAD price, and the concentration of GJ-pp is lower than that of spiro-OMeTAD (50.0 vs. 72.3 mg mL−1). The results demonstrate that the twin-carbazole moiety can endow enhanced charge transport properties due to its potential intermolecular interactions, and the conjugated core is unnecessary for promising HTMs.