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A novel 2-(2,3,4-trimethoxyphenyl)-1H-phenanthro[9,10-d]imidazole crystal has been reported and characterized by FT-IR, 1H NMR, and 13C NMR spectral techniques. Single-crystal XRD studies reveal that the compound crystallizes into orthorhombic crystal system with Pbcn space group, and crystallographic data have been deposited in the Cambridge crystallographic data centre with CCDC number: 2244532. Various computational analyses such as hydrogen bond analysis, molecular electrostatic potential analysis, natural population analysis, Hirshfeld surface, and Frontier molecular orbital analysis were performed to elucidate the structure of the crystal. The calculation of reorganization energy and coupling constant using DFT methods reveals that the compound could be investigated as a hole transport material. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

Hydrothermally grown NiO nanoflakes have been investigated here for their resistive switching (RS) and photoabsorption characteristics. The formation and disruption of the conducting filament (CF) under an applied external electric field leads to bistable resistive switching in the grown NiO nanoflakes. Comprehensive investigations of the I–V behaviour show that the formation and rupturing of the CF depend on the concentration of the metallic Ni. Interestingly, photoabsorption response demonstrates a nearly similar behaviour in UV and visible regions for nanoflakes grown at low reaction time, but an enhanced UV response for the flakes obtained at larger reaction times. These nanoflakes displaying multifunctional properties of photoabsorption and RS behaviour, that can be modulated with reaction time, are attractive for optoelectronic, electrochromic and RS-based memory applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Tin oxide (SnO2) has been widely used as an electron transport layer (ETL) in optoelectronic devices. However, there are numerous surface or bulk defects in SnO2, working as charge recombination centers to degrade device. Here, an electroactive and self‐healing polyurethane (PHNN) was designed by integrating conjugated unit – naphthalene diimide (NDI) into a typical polyurethane backbone. Numerous hydrogen bonds and π interactions in PHNN work as non‐covalent interactions to endow this polymer with superior self‐healing properties. PHNN contains lots of aliphatic amine and carbonyl groups, which effectively passivate the defects in SnO2. The π stacking of NDI units will facilitate electron delocalization, endowing PHNN with electrical activity compared with traditional polyurethane. Doping SnO2 with PHNN can improve the conductivity and reduce the work function of SnO2 layer, which is conducive to efficient charge extraction and transport. Using PHNN doped SnO2 as ETL for PM6: Y6 and PM6: BTP‐eC9 based inverted organic solar cells can achieve a high efficiency of 17.16% and 17.51%, respectively. Devices containing doped SnO2 ETL show significantly improved efficiency and stability. Thus, the electroactive polyurethane doped SnO2 interlayers show high performance interfacial modification to align energy‐levels in solar cell devices, which have promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

The polymorphic behavior of conjugated polymers enables tunable optoelectronic properties, but their transport mechanism remains elusive due to the inherent complexity and uncontrollability of polymorphic self‐assembly behaviors and electronic processes at various length scales, alongside the ambiguous relationship between solution and solid states. Herein, precise control of multi‐level supramolecular self‐assembly of a polymorphic conjugated polymer, N‐PDPP4T‐HD with two distinct semi‐crystalline aggregated phases (β1 and β2) via solvent engineering is demonstrated. β1 forms 1D worm‐like nanostructures in solution, whereas β2 generates 2D nanoscale lamellar configuration, confirmed by experimental observation and molecular dynamic simulation. Such solution‐state features are inherited in the solid state (1D nanofibers for β1 and 2D granular‐like structures for β2). X‐ray characterizations reveal larger crystalline domains on the nanometer scale, reduced π‐stacking distance on the Ångstrom scale, and diminished paracrystallinity disorder for solid‐state β2. Going beyond conventional DC transistor characterizations, contact‐free ultrafast terahertz spectroscopy to unveil AC short‐range, intrinsic transport properties is employed. Longer charge carrier scattering time and thus intrinsic mobility of β2 result in threefold higher short‐range photoconductivity than β1. This work establishes the "solution structure – solid structure – local transport" relation in polymorphic conjugated polymers and provides new opportunities for high‐performance plastic electronic devices. [ABSTRACT FROM AUTHOR]

Nickel‐doped cobalt bi‐metal nanoparticles (Ni/Co BMNPs) are employed in the transport buffer layer of thin‐film polymer solar cell to assist in the collection of photons generated current. P3HT:PCBM blend‐based polymer solar cells are successfully fabricated with modified hole transport layer (HTL)‐containing BMNPs at different concentrations. The performance of the devices has generally improved compared to the reference cell by the presence of BMNPs in the transport buffer layer, and shows sign of dependence on concentration level. Significant improvements in device performance are recorded at optimum level of 0.05% BMNPs by weight, which resulted in a high current density of 15.31 mA cm−2, and recorded 5.05% power conversion efficiency (PCE). This is 67.8% growth in PCE is compared to the reference cell. Moreover, another investigation is conducted using device simulation program to check the reproducibility of the experiments. The device that is made to mimic the best performance at 0.05% BNMP concentration produced an efficiency of 5.76%. Such reproducibility of data is an important development toward better understanding of the charge transport process in polymer solar cell. This study further provides new evidences about factors that influence device performance due to the inclusion of the BMNPs. [ABSTRACT FROM AUTHOR]

The reversible photo-induced conformation transition of a single molecule with a [5]helicene backbone has garnered considerable interest in recent studies. Based on such a switching process, one can build molecular photo-driven switches for potential applications of nanoelectronics. But the achievement of high-performance reversible single-molecule photoswitches is still rare. Here, we theoretically propose a 13,14-dimethylcethrene switch whose photoisomerization between the ring-closed and ring-open forms can be triggered by ultraviolet (UV) and visible light irradiation. The electronic structure transitions and charge transport characteristics, concurrent with the photo-driven electrocyclization of the molecule, are calculated by the non-equilibrium Green's function (NEGF) in combination with density functional theory (DFT). The electrical conductivity bears great diversity between the closed and open configurations, certifying the switching behavior and leading to a maximum on–off ratio of up to 103, which is considerable in organic junctions. Further analysis confirms the evident switching behaviors affected by the molecule–electrode interfaces in molecular junctions. Our findings are helpful for the rational design of organic photoswitches at the single-molecule level based on cethrene and analogous organic molecules. [ABSTRACT FROM AUTHOR]

Herein, a straightforward vacuum‐assisted method is introduced to enhance the stability of nonfullerene organic solar cells (OSCs). The method, termed "prevacuum" involves subjecting the active layer (D18:Y6) to a low‐pressure vacuum (−1 bar) before thermal annealing at 100 °C. Compared to untreated devices, prevacuum‐treated OSCs exhibit a notable increase in power conversion efficiency from 13.71% to 14.90%. This enhancement is attributed to improved light absorption and charge extraction, as evidenced by external quantum efficiency measurements. Moreover, prevacuum treatment significantly improves device stability under operational conditions, with a 30% power loss occurring after 8.25 h compared to 4.5 h for untreated devices. This improvement is attributed to the removal of volatile components and impurities during the vacuum process, leading to a more hydrophobic and stable active layer. The study demonstrates the efficacy of prevacuum treatment as a simple and accessible method for enhancing the performance and longevity of OSCs, paving the way for their broader application in sustainable energy technologies. [ABSTRACT FROM AUTHOR]

The design of photocatalytic supramolecular systems composing of semiconductors and molecular metal complexes for CO2 reduction has attracted increasing attention. The supramolecular system combines the structural merits of semiconductors and metal complexes, where the semiconductor harvests light and undertakes the oxidative site, while the metal complex provides activity for CO2 reduction. The intermolecular charge transfer plays crucial role in ensuring photocatalytic performance. Here, we review the progress of photocatalytic supramolecular systems in reduction of CO2 and highlight the interfacial charge transfer pathways, as well as their state‐of‐the‐art characterization methods. The remaining challenges and prospects for further design of supramolecular photocatalysts are also presented. [ABSTRACT FROM AUTHOR]

The optoelectronic properties of semiconducting polymers and device performance rely on a delicate interplay of design and processing conditions. However, screening and optimizing the relationships between these parameters for reliably fabricating organic electronics can be an arduous task requiring significant time and resources. To overcome this challenge, Polybot is developed—a robotic platform within a self‐driving lab that can efficiently produce organic field‐effect transistors (OFETs) from various semiconducting polymers via high‐throughput blade coating deposition. Polybot not only handles the fabrication process but also can conduct characterization tests on the devices and autonomously analyze the data gathered, thus facilitating the rapid acquisition of data on a large scale. This work leverages the capabilities of this platform to investigate the fabrication of OFETs using hydrogen bonding‐containing semiconducting polymers. Through high‐throughput fabrication and characterization, various data trends are analyzed, and large extents of anisotropic charge mobility are observed in devices. The materials are thoroughly characterized to understand the role of processing conditions in solid state and electronic properties of these organic semiconductors. The findings demonstrate the effectiveness of automated fabrication and characterization platforms in uncovering novel structure–property relationships, facilitating refinement of rational chemical design, and processing conditions, ultimately leading to new semiconducting materials. [ABSTRACT FROM AUTHOR]

Asymmetric wide‐band gap fullerene‐free acceptors (FFAs) play a crucial role in organic solar cells (OSCs). Here, we designed and synthesized a simple asymmetric coumarin‐anthracene conjugate named CA‐CN with optical band gap of 2.1 eV in a single‐step condensation reaction. Single crystal X‐ray structure analysis confirms various multiple intermolecular non‐covalent interactions. The molecular orbital energy levels of CA‐CN estimated from cyclic voltammetry were found to be suitable for its use as an acceptor for OSCs. Binary OSCs fabricated using CA‐CN as acceptor and PTB7‐Th as the donor achieve a power conversion efficiency (PCE) of 11.13 %. We further demonstrate that the insertion of 20 wt % of CA‐CN as a third component in ternary OSCs with PTB7‐Th : DICTF as the host material achieved an impressive PCE of 14.91 %, an improvement of ~43 % compared to the PTB7‐Th : DICTF binary device (10.38 %). Importantly, the ternary blend enhances the absorption coverage from 400 to 800 nm and improves the morphology of the active layer. The findings highlight the efficacy of an asymmetric design approach for FFAs, which paves the way for developing high‐efficiency OSCs at low cost. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of an instationary drift-diffusion model for perovskite solar cells including Fermi–Dirac statistics for electrons and holes and Blakemore statistics for the mobile ionic vacancies in the perovskite layer. The free energy functional is related to this choice of the statistical relations.Exemplary simulations varying the mobility of the ionic vacancy demonstrate the necessity to include the migration of ionic vacancies in the model frame. To prove the existence of weak solutions, first a problem with regularized state equations and reaction terms on any arbitrarily chosen finite time interval is considered. Its solvability follows from a time discretization argument and passage to the time-continuous limit. Applying Moser iteration techniques, a priori estimates for densities, chemical potentials and the electrostatic potential of its solutions are derived that are independent of the regularization level, which in turn ensure the existence of solutions to the original problem. [ABSTRACT FROM AUTHOR]

Antimony-based perovskites have been recognized for their distinctive optoelectronic attributes, standard fabrication methodologies, reduced toxicity, and enhanced stability. The objective of this study is to systematically investigate and enhance the performance of all-inorganic solar cell architectures by integrating Cs3Sb2I9, a perovskite-analogous material, with WS2—a promising transition metal dichalcogenide—used as the electron transport layer (ETL), and Cu2O serving as the hole transport layer (HTL). This comprehensive assessment extends beyond the mere characterization of material attributes such as layer thickness, doping levels, and defect densities, to include a thorough investigation of interfacial defect effects within the structure. Optimal efficiency was observed when the Cs3Sb2I9 absorber layer thickness was maintained within the 600-700 nm range. The defect tolerance for the absorber layer was identified at 1×1015/cm3, with the ETL and HTL layers exhibiting significant defect tolerance at 1×1016/cm3 and 1×1017/cm3, respectively. Furthermore, this study calculated the minority carrier lifetime and diffusion length, establishing a strong correlation with defect density; a minority carrier lifetime of approximately 1 µs was noted for a defect density of1×1014/cm3 in the absorber layer. A noteworthy finding pertains to the balance between the high work function of the back contact and the incorporation of p-type back surface field layers, revealing that interposing a highly doped p+ layer between the Cu2O and the metal back contact can elevate the efficiency to 21.60%. This approach also provides the freedom to select metals with lower work functions, offering a cost-effective advantage for commercial-scale applications.

The I-V characteristics of heterostructures n-GaAs – p-(ZnSe)1–x–y(Ge2)x(GaAs1–δBiδ) exhibit a characteristic quadratic law - J~V2 I-V curve, followed by a sharp pre-breakdown current growth, which well explains the observed straight branch of the I-V characteristics and this regularity remains unchanged at different temperatures. The analysis of the I-V characteristics of n‑GaAs‑p‑(ZnSe)1‑x‑y(Ge2)x(GaAs1–δBiδ) heterostructures with an extended intermediate solid solution layer shows that the drift mechanism of charge transport predominates under forward bias conditions.

The development of n‐type organic thermoelectric materials, especially π‐conjugated small molecules, lags far behind their p‐type counterparts, due primarily to the scarcity of efficient electron‐transporting molecules and the typically low electron affinities of n‐type conjugated molecules that leads to inefficient n‐doping. Herein, the n‐doping of two functionalized (carbonyl vs dicyanovinylene) indenofluorene‐based conjugated small molecules, 2,8‐bis(5‐(2‐octyldodecyl)thien‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐dione (TIFDKT) and 2,2′‐(2,8‐bis(3‐alkylthiophen‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐diylidene)dimalononitrile (TIFDMT) are demonstrated, with n‐type dopant N‐DMBI. While TIFDKT shows decent miscibility with N‐DMBI, it can be hardly n‐doped owing to its insufficiently low LUMO. On the other hand, TIFDMT, despite a poorer miscibility with N‐DMBI, can be efficiently n‐doped, reaching a respectable electrical conductivity of 0.16 S cm−1. Electron paramagnetic resonance measurements confirm the efficient n‐doping of TIFDMT. Based on density functional theory (DFT) calculations, the LUMO frontier orbital energy of TIFDMT is much lower, and its wave function is more delocalized compared to TIFDKT. Additionally, the polarons are more delocalized in the n‐doped TIFDMT. Remarkably, as indicated by the grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the molecular order for TIFDMT thin‐film is enhanced by n‐doping, leading to more favorable packing with edge‐on orientation and shorter π‐π stacking distances (from 3.61 to 3.36 Å). This induces more efficient charge transport in the doped state. Upon optimization, a decent thermoelectric power factor of 0.25 µWm−1K−2 is achieved for n‐doped TIFDMT. This work reveals the effect of carbonyl vs dicyanovinylene on the n‐doping efficiency, microstructure evolution upon doping and thermoelectric performance, offering a stepping stone for the future design of efficient n‐type thermoelectric molecules. [ABSTRACT FROM AUTHOR]

The incorporation of heteroatoms in the chemical structure of organic molecules has been identified as analogous to the doping process adopted in silicon semiconductors to influence the nature of charge carriers. This strategy has been an eye‐opener for material chemists in synthesizing new materials for optoelectronic applications. Phenanthro[9,10‐a]phenazine‐based mesogens have been synthesized via a cyclo‐condensation pathway involving triphenylene‐based diketone and o‐phenyl diamines. The incorporation of phenazine moiety as discussed in this paper, alters the symmetric nature of the triphenylene. The phenanthro[9,10‐a]phenazine‐based mesogens exhibit hole mobility in the order of 10−4 cm2/Vs as measured by the space‐charge limited current (SCLC) technique. The current density in the SCLC device increases with increasing temperature which indicates that the charge transport is associated with the thermally activated hopping process. This report attempts to elucidate the self‐organization of asymmetric phenanthro[9,10‐a] phenazine in the supramolecular liquid crystalline state and their potential for the fabrication of high‐temperature optoelectronic devices. However, the low charge carrier mobility can be one of the challenges for device performance. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) perovskites show structural stability and tunability and are regarded as promising photovoltaic materials. The spacer cations play an important impact on exciton separation and charge transport of 2D perovskites. Herein, a novel spacer with thiazole as core, 2‐thiazolemethanammonium (AMT), owning characters of small molecular size, delocalized π‐electrons, and strong electron‐withdrawing ability, is introduced to construct 2D DJ perovskites. Owing to the strong orbital coupling between AMT spacer and inorganic layers, the AMT‐based perovskite exhibits type II quantum well structure, which is favorable for exciton separation. On contrary, such interaction does not appear in the DJ perovskite when aliphatic propyldiammonium (PDA), with a similar length, is used as spacer. The AMT spacer can also induce better crystallinity, resulting in reduced defect density and improved charge transport ability. The optimized device based on (AMT)MA3Pb4I13 exhibits a power conversion efficiency (PCE) of 19.69%, which is a record for 2D DJ perovskite solar cells (PSCs) (n ≤ 4). This work provides deep understanding of the impact of aromatic spacer on the electronic structure of 2D DJ perovskites and the corresponding photovoltaic performance and provides a new opportunity toward highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

The nature of interchain π-system contacts, and their relationship to hole transport, are elucidated for the high-mobility, noncrystalline conjugated polymer C16-IDTBT by the application of scanning tunneling microscopy, molecular dynamics, and quantum chemical calculations. The microstructure is shown to favor an unusual packing motif in which paired chains cross-over one another at near-perpendicular angles. By linking to mesoscale microstructural features, revealed by coarse-grained molecular dynamics and previous studies, and performing simulations of charge transport, it is demonstrated that the high mobility of C16-IDTBT can be explained by the promotion of a highly interconnected transport network, stemming from the adoption of perpendicular contacts at the nanoscale, in combination with fast intrachain transport. [ABSTRACT FROM AUTHOR]

Interfacial defects and energy level mismatches between the perovskite and 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (Spiro‐OMeTAD) layers heavily hinder charge transfer, limiting the efficiency and stability of n‐i‐p perovskite solar cells (PSCs). Herein, D‐type TPA, D‐A‐type TPA‐CN, and A‐D‐A‐type DTPA‐CN with triphenylamine units and different interfacial dipoles are designed as multifunctional interfacial layers for n‐i‐p PSCs. Among the three molecules, A‐D‐A‐type DTPA‐CN has the largest dipole moment, hole transporting capability, and hydrophobicity, and therefore the strongest passivation of interfacial defects and the best carrier extraction efficiency can be observed. As a result, the DTPA‐CN‐treated device achieves a champion power conversion efficiency (PCE) of 25.00%, as compared to the control device (22.78%). Moreover, the long‐term stability of the unencapsulated device is significantly improved. After 2,040 h of storage in a nitrogen glove box, the device maintains over 90% of its initial efficiency, while only 61% for the control device. The work indicates that simultaneous improvement of trap passivation and hole extraction is critical for achieving highly efficient and stable n‐i‐p PSCs. [ABSTRACT FROM AUTHOR]

Developing long‐chain molecules with stable helical structures is of significant importance for understanding and modulating the properties and functions of helical biological macromolecules, but challenging. In this work, an effective and facile approach to stabilize folded helical structures by strengthening through‐space conjugation is proposed, using new ortho‐hexaphenylene (o‐HP) derivatives as models. The structure–activity relationship between the through‐space conjugation and charge‐transport behavior of the prepared folded helical o‐HP derivatives is experimentally and theoretically investigated. It is demonstrated that the through‐space conjugation within o‐HP derivatives can be strengthened by introducing electron‐withdrawing pyridine and pyrazine rings, which can effectively stabilize the helical structures of o‐HP derivatives. Moreover, scanning tunneling microscopy‐break junction measurements reveal that the stable regular helical structures of o‐HP derivatives open‐up dominant through‐space charge‐transport pathways, and the single‐molecule conductance is enhanced by more than 70 % by strengthening through‐space conjugation with pyridine and pyrazine. However, the through‐bond charge transport pathways contribute much less to the conductance of o‐HP derivatives. These results not only provide a new method for exploring stable helical molecules, but also provide a stepping stone for deciphering and modulating the charge‐transport behavior of helical systems at the single‐molecule level. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) perovskite solar cells (PSCs) exhibit better stability compared with three‐dimensional PSCs. However, fundamental questions remain over the chemical phase space in the 2D perovskite framework. Here, phase distribution of alternating cations in the interlayer space 2D perovskite (GA(MA)nPbnI3n+1) is regulated by using potassium salt to control the assembly behavior of colloidal particles and manage the growth of quantum well. The strong affinity between the spacer cation and sulfonate can slow down the intercalation of organic spacer cations to provide a time window for the insertion of MA+, which is conducive to forming high n phase to facilitate the charge transportation. During the crystallization process, potassium salt is extruded to the grain boundary and produce a passivation effect. In this case, the ion migration channels and inlet of water and oxygen are cut off, which is beneficial for the stability of PSCs. A power conversion efficiency of 20.90% is obtained in this work, to the best knowledge, which is the highest PCE for all reported GA(MA)3Pb3I10 perovskite and the large‐area device (1.01 cm2) shows a high efficiency of 18.73 %. Besides, the devices deliver good humidity stability. [ABSTRACT FROM AUTHOR]

In the quest to improve energy efficiency and design better thermal insulators, various engineering strategies have been extensively investigated to minimize heat transfer through a material. Yet, the suppression of thermal transport in a material remains elusive because heat can be transferred by multiple energy carriers. Here, the realization of Anderson localization of phonons in a random 3D elastic network of graphene is reported. It is shown that thermal conductivity in a cellular graphene aerogel can be drastically reduced to 0.9 mW m−1 K−1 by the application of compressive strain while keeping a high metal‐like electrical conductivity of 120 S m−1 and ampacity of 0.9 A. The experiments reveal that the strain can cause phonon localization over a broad compression range. The remaining heat flow in the material is dominated by charge transport. Conversely, electrical conductivity exhibits a gradual increase with increasing compressive strain, opposite to the thermal conductivity. These results imply that strain engineering provides the ability to independently tune charge and heat transport, establishing a new paradigm for controlling phonon and charge conduction in solids. This approach will enable the development of a new type of high‐performance insulation solutions and thermally superinsulating materials with metal‐like electrical conductivity. [ABSTRACT FROM AUTHOR]

Traditionally used phenylethylamine iodide (PEAI) and its derivatives, such as ortho‐fluorine o‐F‐PEAI, in interfacial modification, are beneficial for perovskite solar cell (PSC) efficiency but vulnerable to heat stability above 85 °C due to ion migration. To address this issue, we propose a composite interface modification layer incorporating the discotic liquid crystal 2,3,6,7,10,11‐hexa(pentoxy)triphenylene (HAT5) into o‐F‐PEAI. The triphenyl core in HAT5 promotes π–π stacking self‐assembly and enhances its interaction with o‐F‐PEAI, forming an oriented columnar phase that improves hole extraction along the one‐dimensional direction. HAT5 repairs structural defects in the interfacial layer and retains the layered structure to inhibit ion migration under heating. Ultimately, our approach increases the efficiency of solar cells from 23.36 % to 25.02 %. The thermal stability of the devices retains 80.1 % of their initial efficiency after aging at 85 °C for 1008 hours without encapsulation. Moreover, the optimized PSCs maintained 82.4 % of the initial efficiency after aging under one sunlight exposure for 1008 hours. This work provides a simple yet effective strategy using composite materials for interface modification to enhance the thermal and light stability of semiconductor devices. [ABSTRACT FROM AUTHOR]

In organic field‐effect transistors (OFETs) using disordered organic semiconductors, interface traps that hinder efficient charge transport, stability, and device performance are inevitable. Benchmark poly(9,9‐dioctylfuorene‐co‐bithiophene) (F8T2) liquid‐crystalline polymer semiconductor has been extensively investigated for organic electronic devices due to its promising combination of charge transport and light emission properties. This study demonstrates that high‐capacitance single‐layered ionic polyurethane (PU) dielectrics enable enhanced charge transport in F8T2 OFETs. The ionic PU dielectrics are composed of a mild blending of PU ionogel and PU solution, thereby forming a solid‐state film with robust interfacial characteristics with semiconductor layer and gate electrode in OFETs and measuring high capacitance values above 10 µF cm−2 owing to the combined dipole polarization and electric double layer formation. The optimized fabricated ionic PU‐gated OFETs exhibit a low‐voltage operation at −3 V with a remarkable hole mobility of over 5 cm2 V–1 s–1 (average = 2.50 ± 1.18 cm2 V–1 s–1), which is the highest mobility achieved so far for liquid‐crystalline F8T2 OFETs. This device also provides excellent bias‐stable characteristics in ambient air, exhibiting a negligible threshold voltage shift of −0.03 V in the transfer curves after extended bias stress, with a reduced trap density. [ABSTRACT FROM AUTHOR]

The construction of anatase/rutile heterojunctions in TiO2 is an effective way of improving the CO2 photoreduction activity. Yet, the origin of the superior photocatalytic performance is still unclear. To solve this issue, the band edges between anatase and rutile phases were theoretically determined based on the three-phase atomic model of (112)A/II/(101)R, and simultaneously the CO2 reduction processes were meticulously investigated. Our calculations show that photogenerated holes can move readily from anatase to rutile via the thin intermediated II phase, while photoelectrons flowing in the opposite direction may be impeded due to the electron trapping sites at the II phase. However, the large potential drop across the anatase/rutile interface and the strong built-in electric field can provide an effective driving force for photoelectrons' migration to anatase. In addition, the II phase can better enhance the solar light utilization of (112)A/(100)II, including a wide light response range and an intensive optical absorption coefficient. Meanwhile, the mixed-phase TiO2 possesses negligible hydrogenation energy (CO2 to COOH*) and lower rate-limiting energy (HCOOH* to HCO*), which greatly facilitate CH3OH generation. The efficient charge separation, strengthened light absorption, and facile CO2 reduction successfully demonstrate that the anatase/rutile mixed-phase TiO2 is an efficient photocatalyst utilized for CO2 conversion. [ABSTRACT FROM AUTHOR]

Organometallic halide perovskites have shown significant promise for applications in optoelectronics and photovoltaics in recent years. This research looks into the performance of bulk heterojunction-based photodetectors (PDs) based on the active layer of a CH3NH3PbI3:PCBM bulk heterojunction (BHJ). We assessed the impact of PCBM concentration in CH3NH3PbI3:PCBM BHJ on the electrical performance of the PDs. We found that the BHJ PD with a 4% PCBM concentration had the strongest capability to reject noise, as demonstrated by its superior ratio of photocurrent to dark current. Moreover, the PD with a 4% PCBM concentration in the active layer outperforms pristine CH3NH3PbI3-based PDs in terms of optoelectronic performance, showing greater responsivity and detectivity. The improved optoelectronic performance of BHJ PD is due to increased interfacial area, higher electron extraction and a decrease in traps and defects. The analysis of dark current–voltage curves reveals a significant reduction in charge recombination for BHJ devices, supporting the elimination of traps and defects by the inclusion of PCBM. The PD’s impedance study unveils that the incorporation of PCBM enhances charge transfer and effectively suppresses charge recombination, leading to enhanced optoelectronic performance. [ABSTRACT FROM AUTHOR]

The distribution of density of states (DOS) holds fundamental importance in determining charge transport within organic field–effect transistors (OFETs). Herein, the modulation of DOS distribution in OFET devices is demonstrated by altering the chain conformation of the polymer dielectrics. A rapid film‐formation technique, specifically the spin‐casting method, is used to fabricate the dielectric layer using poly(methyl methacrylate) (PMMA). This method allows for the retention of some memory of the chain conformations from the solution to the resulting dry film. This memory effect is employed to prepare thin PMMA films with different local chain conformations by adjusting the quality of the solvent. Good solvent forms solidified films with a reduced amount of gauche conformer in the PMMA chain, resulting in a narrow DOS distribution width. Consequently, the device exhibited enhanced charge mobility and a reduced subthreshold swing. The observed change in the width of the DOS distribution can be attributed to the alteration of the local energy state of the semiconductor, induced by the local chain conformation of PMMA dielectrics through electrostatics and steric interactions. [ABSTRACT FROM AUTHOR]

The charge carrier mobility in tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA), a host and hole transport material typically used in organic light‐emitting diodes (OLEDs), is measured using charge carrier electrical injection metal–insulator–semiconductor charge extraction by linearly increasing voltage (i‐MIS‐CELIV). By employing the injection current i‐MIS‐CELIV method, charge transport at time scales shorter than the transit times typically observed in standard MIS‐CELIV is measured. The i‐MIS‐CELIV technique enables the experimental measurement of unequilibrated and pretrapped charge carriers. Through a comparison of injection and extraction current transients obtained from i‐MIS‐CELIV and MIS‐CELIV, it is concluded that hole trapping is negligible in evaporated neat films of TCTA within the time‐scales relevant to the operational conditions of optoelectronic devices, such as OLEDs. Furthermore, photocarrier generation in conjunction with i‐MIS‐CELIV (photo‐i‐MIS‐CELIV) to quantify the properties of charge injection from the electrode to the semiconductor of the MIS devices is utilized. Based on the photo‐i‐MIS‐CELIV measurements, it is observed that the contact resistance does not limit the injection current at the TCTA/molybdenum oxide/silver interface. Therefore, when TCTA is employed as the hole transport/electron‐blocking layer in OLEDs, it does not significantly reduce the injection current and remains compatible with the high injection current densities required for efficient OLED operation. [ABSTRACT FROM AUTHOR]

Thin film solar cells are gaining popularity as an affordable, efficient, and flexible substitute for traditional silicon solar cells . This success is closely tied to the deposition techniques used to fabricate their layers. This review explores and analyzes the advances in the major deposition techniques for solar cell applications, offering insights into their underlying principles, associated advantages, drawbacks, and suitability for diverse materials and device architectures. The two primary deposition for thin film solar cells are PVD and CVD. In PVC materials are physically ejecting from a target, and depositing it onto a substrate. While, CVD entails the reaction of gases or vapour precursors to creating film on a substrate. The ability to achieve high purity, control over film properties, scalability, and compatibility with flexible substrates are notable advantages. However, challenges such as high costs and complexity can impact the commercial viability of certain techniques. Recent advancements in the technology of thin film deposition for solar cells include the discovery of novel materials with enhanced light absorption and electronic charge transport capabilities, emerging deposition processes such as pulsed laser deposition, and atomic layer deposition scalable and low-cost processes like roll-to-roll processing, and integration with other technologies like perovskite solar cells and tandem devices. Understanding these techniques and staying informed about recent advancements and future directions empowers researchers and engineers to innovate and create improved thin film solar cells, contributing significantly to a more sustainable future through enhanced solar energy harvesting technologies. [ABSTRACT FROM AUTHOR]

Thermoelectric (TE) charge transport in organic TE nanocomposite systems is a critical consideration in designing high‐performance TE materials. Here, the relationship between the TE properties and energy structure of conducting polymer/quantum dot (QD) nanocomposites is systematically investigated by developing a potential wall or potential well in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with CdTe QDs. The added QDs are primarily distributed within the electrically insulating PSS shell and act as stepping stones for charge transport between PEDOT‐rich grains. The embedded QDs generate an energy‐filtering effect, which is induced by both potential wall and potential well states established by the QDs in the PEDOT:PSS films. The induced energy‐filtering effect increases the Seebeck coefficient S with limited loss of electrical conductivity σ, thereby overcoming the TE trade‐off relation S ∝ σ−1/4. The energy‐filtering effect is optimized by carefully controlling the QD size. The PEDOT:PSS/QD nanocomposite containing the smallest QDs exhibits a power factor of 173.8 µW m−1 K−2, which is 80% larger than the value for the pristine PEDOT:PSS film. This work suggests a strategy for designing TE nanocomposites with improved TE performance and emphasizes the importance of fine‐tuning the interfacial energy gap to achieve an effective energy‐filtering effect. [ABSTRACT FROM AUTHOR]

Quasi‐2D perovskites have attracted significant attention because of their environmental robustness and superior long‐term stability compared with their 3D counterparts. However, they typically consist of a mixture of multiple quantum wells with different optoelectrical properties, which degrades the electronic properties and hinders further electronic applications. Here, to challenge this issue, a surface p‐doping strategy involving the introduction of a thiophene‐containing polymer onto the surface of quasi‐2D tin perovskites is reported. The tin ions in the perovskites effectively interact with the sulfur atoms in the thiophene moieties, thereby generating hole carriers and inducing p‐doping. The resulting doped quasi‐2D perovskites exhibit excellent surface crystallinity, lower trap density, and enhanced charge carrier transport capability along the perovskite semiconductor channels. Consequently, the doped quasi‐2D tin perovskite‐based transistors exhibit a high field‐effect mobility of 53 cm2V−1s−1 (7 cm2V−1s−1 for the control device) and an outstanding on/off ratio (>107), together with superior operational stability. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a novel intramolecular donor‐acceptor (D−A) system ([12]CPP‐8TPAOMe) based on cycloparaphenylenes (CPPs) grafted with eight di(4‐methoxyphenyl)amino groups (TPAOMe) as donors. Compared to [12]CPP, D−A nanohoop exhibited significant changes in physical properties, including a large redshift (>78 nm) in the fluorescence spectrum and novel positive solvatofluorochromic properties with a maximum peak ranging from 484 nm to 546 nm. The potential applications of [12]CPP‐8TPAOMe in electron‐ and hole‐transport devices were further investigated, and its bipolar behavior as a charge transport active layer was clearly observed. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have demonstrated remarkable progress in performance in recent years, which has placed perovskite materials as the leading promising materials for future renewable energy applications. The solvent additive technique in perovskite composition is a simple but effective process used to improve the surface quality of the perovskite layers and to improve the performance and charge transport processes essential to the functions of PSCs. These additives can have a considerable effect on the topography, crystallinity, and surface properties of the perovskite active layer, ultimately influencing the stability of the PSCs. A "two-step spin coating" deposition method to make PSCs in ambient air laboratory conditions was employed. Acetonitrile (ACN) was conventionally utilized as a chemical additive to enhance the performance of PSCs. In this study, our film properties exhibited that the incorporation of ACN in the triple cation perovskite precursor led to the passivation of surface defects and a noticeable increase in the size of the crystal grains of the perovskite films, which led to enhanced stability of devices. The efficiency achieved for PSCs prepared with 10% ACN was 15.35%, which is 30% higher than devices prepared without ACN. In addition, devices prepared with ACN have shown a lower hysteresis index and more stable behavior compared to devices prepared without ACN. This work presents an easy, low-cost method for the fabrication of high performance PSCs prepared under ambient air laboratory conditions. [ABSTRACT FROM AUTHOR]

Organosilicate glass (OSG) films are a critical component in modern electronic devices, with their electrical properties playing a crucial role in device performance. This comprehensive review systematically examines the influence of chemical composition, vacuum ultraviolet (VUV) irradiation, and plasma treatment on the electrical properties of these films. Through an extensive survey of literature and experimental findings, we elucidate the intricate interplay between these factors and the resulting alterations in electrical conductivity, dielectric constant, and breakdown strength of OSG films. Key focus areas include the impact of diverse organic moieties incorporated into the silica matrix, the effects of VUV irradiation on film properties, and the modifications induced by various plasma treatment techniques. Furthermore, the underlying mechanisms governing these phenomena are discussed, shedding light on the complex molecular interactions and structural rearrangements occurring within OSG films under different environmental conditions. It is shown that phonon-assisted electron tunneling between adjacent neutral traps provides a more accurate description of charge transport in OSG low-k materials compared to the previously reported Fowler–Nordheim mechanism. Additionally, the quality of low-k materials significantly influences the behavior of leakage currents. Materials retaining residual porogens or adsorbed water on pore walls show electrical conductivity directly correlated with pore surface area and porosity. Conversely, porogen-free materials, developed by Urbanowicz, exhibit leakage currents that are independent of porosity. This underscores the critical importance of considering internal defects such as oxygen-deficient centers (ODC) or similar entities in understanding the electrical properties of these materials. [ABSTRACT FROM AUTHOR]

One hindrance in transparent electronics is the lack of high‐performance p‐type transparent conductors (TCs). The state‐of‐the‐art p‐type TC, CuI, has a conductivity two orders of magnitude lower than n‐type TCs like ITO. While doping strategies have shown promise in enhancing the hole carrier density in CuI, they often come at the expense of hole mobility. Therefore, understanding how extrinsic dopants affect the mobility of CuI is critical to further improve the performance of CuI‐based TCs. Here the structural and electronic properties of Cs‐doped CuI are investigated. It is demonstrated that ≈4 at.% Cs doping in CuI increases the carrier density from 2.1 × 1019 to 3.8 × 1020 cm−3 while preserving the film microstructure and local coordination of Cu, as confirmed by HRTEM and XAS analysis. Introducing S as a co‐dopant in Cs:CuI boosts the carrier density to 8.2 × 1020 cm−3, reaching a stable conductivity of ≈450 S cm−1. In all cases, the enhanced carrier density negatively affects the hole mobility with ionized impurity scattering and increased Seebeck hole effective mass as mobility limiting mechanisms. Nonetheless, the new Cs, S co‐doped CuI exhibits high p‐type conductivity, Vis–NIR transparency, and stability, presenting an attractive candidate for future transparent electronic devices. [ABSTRACT FROM AUTHOR]

Nanohoops, cyclic association of π‐conjugated systems to form a hoop‐shaped molecule, have been widely developed in the last 15 years. Beyond the synthetic challenge, the strong interest towards these molecules arises from their radially oriented π‐orbitals, which provide singular properties to these fascinating structures. Thanks to their particular cylindrical arrangement, this new generation of curved molecules have been already used in many applications such as host–guest complexation, biosensing, bioimaging, solid‐state emission and catalysis. However, their potential in organic electronics has only started to be explored. From the first incorporation as an emitter in a fluorescent organic light emitting diode (OLED), to the recent first incorporation as a host in phosphorescent OLEDs or as charge transporter in organic field‐effect transistors and in organic photovoltaics, this field has shown important breakthroughs in recent years. These findings have revealed that curved materials can play a key role in the future and can even be more efficient than their linear counterparts. This can have important repercussions for the future of electronics. Time has now come to overview the different nanohoops used to date in electronic devices in order to stimulate the future molecular designs of functional materials based on these macrocycles. [ABSTRACT FROM AUTHOR]

The mechanically cleaved flake of ternary metal chalcogenide PbSnSe 2 was transferred onto the interdigitated electrodes to form electrical contacts. The temperature dependent (180 K–250 K) electrical properties were then analyzed employing complex impedance spectroscopy from 2 kHz to 2 MHz. A detailed analysis of Nyquist plots proposed the space charge dependent behavior and negative temperature coefficient of PbSnSe 2 flake. The AC conductivity followed Jonscher's power law with s -parameter value being less than unity. The values of s -parameter increased with rise in temperature suggesting the presence of non-overlapping small polaron tunneling (NSPT) in the PbSnSe 2 flake. From this NSPT model, tunneling distance, hopping energy, and density of states (DOS) were estimated at temperatures from 180 K–250 K. The dielectric permittivity showed dispersion at lower frequencies and the tangent loss was also found to be directly related to temperature. A single semicircular arc in complex modulus analysis showed the dominance of bulk effect in the material. [ABSTRACT FROM AUTHOR]

Polarons, which arise from the intricate interplay between excess electrons and/or holes and lattice vibrations (phonons), represent quasiparticles pivotal to the electronic behavior of materials. This review reaffirms the established classification of small and large polarons, emphasizing its relevance in the context of recent advances in understanding lead halide perovskites' behavior. The distinct characteristics of large and small polarons stem from the electron–phonon interaction range, which exerts a profound influence on materials' characteristics and functionalities. Concurrently, lead halides have emerged with exceptional opto‐electronic properties, featuring prolonged carrier lifetimes, low recombination rates, high defect tolerance, and moderate charge carrier mobilities; these characteristics make them a compelling contender for integration of optoelectronic devices. In this review, the formation of both small and large polarons within the lattice of lead halide perovskites, elucidating their role in protecting photogenerated charge carriers from recombination processes, is discussed. As optoelectronic devices continue to advance, this review underscores the importance of unraveling polaron dynamics to pave the way for innovative strategies for enhancing the performance of next‐generation photovoltaic technologies. Future research should explore novel polaronic effects using advanced computational and experimental techniques, enhancing our understanding and unlocking new applications in materials science and device engineering. [ABSTRACT FROM AUTHOR]

The I-V characteristics of heterostructures n-GaAsp-(ZnSe)1-x-y(Ge2)x(GaAs1-δBiδ) exhibit a characteristic quadratic law - J~V² I-V curve, followed by a sharp pre-breakdown current growth, which well explains the observed straight branch of the I-V characteristics and this regularity remains unchanged at different temperatures. The analysis of the I-V characteristics of n-GaAs-p-(ZnSe) 1-x-y(Ge2)x(GaAs1-δBiδ) heterostructures with an extended intermediate solid solution layer shows that the drift mechanism of charge transport predominates under forward bias conditions. [ABSTRACT FROM AUTHOR]

Outstanding charge transport in molecular crystals is of great importance in modern electronics and optoelectronics. The widely adopted strategies to enhance charge transport, such as restraining intermolecular vibration, are mostly limited to organic molecules, which are nearly inoperative in 2D inorganic molecular crystals currently. In this contribution, charge transport in 2D inorganic molecular crystals is improved by integrating charge‐delocalized Se8 rings as building blocks, where the delocalized electrons on Se8 rings lift the intermolecular orbitals overlap, offering efficient charge transfer channels. Besides, α‐Se flakes composed of charge‐delocalized Se8 rings possess small exciton binding energy. Benefitting from these, α‐Se flake exhibits excellent photodetection performance with an ultrafast response rate (~5 μs) and a high detectivity of 1.08 × 1011 Jones. These findings contribute to a deeper understanding of the charge transport of 2D inorganic molecular crystals composed of electron‐delocalized inorganic molecules and pave the way for their potential application in optoelectronics. [ABSTRACT FROM AUTHOR]

The increasing global demand for energy and growing environmental concerns emphasize the crucial role of solar energy as a sustainable and nondepletable resource. Solar cells, particularly dye‐sensitized solar cells (DSSCs), have gained prominence due to their efficient conversion of solar power, ecofriendly manufacturing processes, and noteworthy stability. Current research in sustainable energy focuses on transitioning from metal‐based to metal‐free organic materials. Tandem solar cells, combining n‐type and p‐type semiconductors sensitized with diverse photoactive dyes, show potential to surpass thermodynamic limits in photon conversion efficiency. Notably, the exploration of n‐type DSSCs as photoanodes in tandem architectures is promising. However, the absence of efficient p‐type photoactive cathodes remains a significant obstacle. Global research efforts are dedicated to addressing charge recombination issues in NiO‐based devices to enhance the efficiency of p‐type DSSCs. The success of any DSSC hinges on the selection of dyes/sensitizers with suitable anchoring groups, wide absorption in the visible–NIR region, and a high extinction coefficient. This article comprehensively reviews advancements in developing highly efficient p‐type sensitizers, emphasizing their pivotal role in unlocking the full potential of tandem solar cells. [ABSTRACT FROM AUTHOR]

This study investigates the solid-state charge transport properties of the oxidized forms of dioxythiophene-based alternating copolymers consisting of an oligoether-functionalized 3,4-propylenedioxythiophene (ProDOT) copolymerized with different aryl groups, dimethyl ProDOT (DMP), 3,4-ethylenedioxythiophene (EDOT), and 3,4-phenylenedioxythiophene (PheDOT), respectively, to yield copolymers P(OE3)-D, P(OE3)-E, and P(OE3)-Ph. At a dopant concentration of 5 mM FeTos3, the electrical conductivities of these copolymers vary significantly (ranging between 9 and 195 S cm-1) with the EDOT copolymer, P(OE3)-E, achieving the highest electrical conductivity. UV-vis-NIR and X-ray spectroscopies show differences in both susceptibility to oxidative doping and extent of oxidation for the P(OE3) series, with P(OE3)-E being the most doped. Wide-angle X-ray scattering measurements indicate that P(OE3)-E generally demonstrates the lowest paracrystallinity values in the series, as well as relatively small π-π stacking distances. The significant (i.e., order of magnitude) increase in electrical conductivity of doped P(OE3)-E films versus doped P(OE3)-D or P(OE3)-Ph films can therefore be attributed to P(OE3)-E exhibiting both the highest carrier ratios in the P(OE3) series, along with good π-π overlap and local ordering (low paracrystallinity values). Furthermore, these trends in the extent of doping and paracrystallinity are consistent with the reduced Fermi energy level and transport function prefactor parameters calculated using the semilocalized transport (SLoT) model. Observed differences in carrier ratios at the transport edge (ct) and reduced Fermi energies [η(c)] suggest a broader electronic band (better overlap and more delocalization) for the EDOT-incorporating P(OE3)-E polymer relative to P(OE3)-D and P(OE3)-Ph. Ultimately, we rationalize improvements in electrical conductivity due to microstructural and doping enhancements caused by EDOT incorporation, a structure-property relationship worth considering in the future design of highly electrically conductive systems.

Nickel‐doped cobalt bi‐metal nanoparticles (Ni/Co BMNPs) are employed in the transport buffer layer of thin‐film polymer solar cell to assist in the collection of photons generated current. P3HT:PCBM blend‐based polymer solar cells are successfully fabricated with modified hole transport layer (HTL)‐containing BMNPs at different concentrations. The performance of the devices has generally improved compared to the reference cell by the presence of BMNPs in the transport buffer layer, and shows sign of dependence on concentration level. Significant improvements in device performance are recorded at optimum level of 0.05% BMNPs by weight, which resulted in a high current density of 15.31 mA cm−2, and recorded 5.05% power conversion efficiency (PCE). This is 67.8% growth in PCE is compared to the reference cell. Moreover, another investigation is conducted using device simulation program to check the reproducibility of the experiments. The device that is made to mimic the best performance at 0.05% BNMP concentration produced an efficiency of 5.76%. Such reproducibility of data is an important development toward better understanding of the charge transport process in polymer solar cell. This study further provides new evidences about factors that influence device performance due to the inclusion of the BMNPs.

Abstract It is now well‐established that ferroelectric domain walls, at which there are discontinuities in polarization, are usually electrically conducting. Yet, there is a dearth of rather basic information on the physics underpinning conductivity. Here, Kelvin Probe Force Microscopy (KPFM)‐based experiments are reported, which allow significant new insights regarding charge transport at domain walls in ErMnO3. In one set of experiments, KPFM is used to spatially map the Hall potential, developed at the surface of polished single crystals. These maps provide direct experimental evidence that n‐type head‐to‐head domain walls arise in otherwise p‐type material. In another set of experiments, the geometry for current flow is restricted, by cutting sub‐micron thick lamellar slices of ErMnO3 (using a Focused Ion Beam microscope). Separate contacts are made to n and p‐type walls and the potential profiles, when driving source‐drain currents, are measured (again using KPFM). Current‐electric field functions showed Ohmic behaviour for p‐type walls, with an intrinsic room temperature conductivity value of ≈0.4Sm−1. The n‐type walls showed non‐Ohmic behaviour and a significantly lower conductivity, supporting the prediction that electrons are in a polaronic state; an upper bound for the room temperature conductivity of the domains themselves is ≈6 × 10−6Sm−1 at 0.1 MVm−1.

Herein, a route to produce highly electrically conductive doped hydroxymethyl functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) films, termed PEDOT(OH) with metal-like charge transport properties using a fully solution processable precursor polymer is reported. This is achieved via an ester-functionalized PEDOT derivative [PEDOT(EHE)] that is soluble in a range of solvents with excellent film-forming ability. PEDOT(EHE) demonstrates moderate electrical conductivities of 20-60 S cm-1 and hopping-like (i.e., thermally activated) transport when doped with ferric tosylate (FeTos3 ). Upon basic hydrolysis of PEDOT(EHE) films, the electrically insulative side chains are cleaved and washed from the polymer film, leaving a densified film of PEDOT(OH). These films, when optimally doped, reach electrical conductivities of ≈1200 S cm-1 and demonstrate metal-like (i.e., thermally deactivated and band-like) transport properties and high stability at comparable doping levels.

Charge transport in the active layer, which can be effectively modulated by molecular doping of organic semiconductors, significantly affects the photovoltaic performance of organic solar cells (OSCs). However, it is difficult to control the dopant distribution in the bulk heterojunction (BHJ) films, which hinders efficient doping in OSCs. Herein, an effective n‐doping strategy is developed via sequential deposition (SD) of D18 donor and doped acceptor. The favorable vertical component distribution in SD films helps to optimize carrier transport pathways. The SD method confines the n‐dopant N‐DMBI to the acceptor layer, allowing positive effects of molecular doping. Consequently, the doped SD device exhibits superior charge transport with suppressed charge recombination, lower trap density, and enhanced charge extraction compared to the undoped one, resulting in a high power conversion efficiency of 19.55% for D18/L8‐BO binary OSCs. In addition, the doping does not affect the thermal stability of the devices, with the doped SD device retaining over 90% of its initial efficiency after 1200 h of heating at 80 °C. The universality of the SD doping method is also verified in other non‐fullerene acceptor systems. These results demonstrate the great potential of SD doping strategy for building high‐performance OSCs with enhanced charge transport. [ABSTRACT FROM AUTHOR]

It remains challenging to comprehensively understand the packing models of conjugated polymers, in which side chains play extremely critical roles. The side chains are typically flexible and non‐conductive and are widely used to improve the polymer solubility in organic solutions. Herein, a buffer chain model is proposed to describe link between conjugated backbone and side chains for understanding the relationship of crystallization competition of conductive conjugated backbones and non‐conductive side chains. A longer buffer chain is beneficial for alleviating such crystallization competition and further promoting the spontaneous packing of conjugated backbones, resulting in enhanced charge transport properties. Our results provide a novel concept for designing conjugated polymers towards ordered organization and enhanced electronic properties and highlight the importance of balancing the competitive interactions between different parts of conjugated polymers. [ABSTRACT FROM AUTHOR]

Sub‐monolayer networks of the electron‐transporting semiconducting polymer poly([N,N'‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)−2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)) (P(NDI2OD‐T2)) are realized through judicious choice of spin‐coating solvent and control of solution concentration. These sub‐monolayer networks provide a platform to study the effects of surface coverage, network connectivity, and orientational order on charge transport. It is found that charge transport through semiconducting polymer networks depends not only on the coverage/concentration of the material but also on the nature of the conduction paths themselves. Down to 40% surface coverage, current measured in a field‐effect architecture decreases in line with the decrease in surface coverage, but drops precipitously below a surface coverage of 40%. Below 40% surface coverage, there is a marked decrease in network connectivity (quantified through the branching point density) and a decrease in orientational order. Furthermore, an increase in the density of dangling branches (dead ends) is also seen with decreasing surface coverage. Additional supporting data in the form of grazing incidence wide‐angle X‐ray scattering (GIWAXS), optical spectroscopy, and charge modulation spectroscopy are presented, which help to establish that long‐range interconnectivity rather than local morphology dominates charge transport in P(NDI2OD‐T2) sub‐monolayers as well as thin films. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Investigating the quantum interference effect in single molecules is essential to comprehensively understand the underlying mechanism of single‐molecule charge transport. In this study, we employed the mother molecule m‐OPE and introduced a series of side groups with various electronic effects at the 2‐position of the central phenyl ring, creating four daughter m‐OPE derivatives. The single molecular conductivities of these molecule wires were measured using the scanning tunneling microscope breaking junction technique. Our findings demonstrate that the substitutions regularly modulate the destructive quantum interference occurring within the m‐OPE molecules. By combining optical and electrochemical investigations, along with density functional theory computations, we discover that the conductivity of the molecules corresponds to the electron‐donating/withdrawing ability of the substituents. Specifically, by adjusting the electron structures of the molecular backbone, we can systematically tailor the destructive quantum interference in the m‐OPE molecules. [ABSTRACT FROM AUTHOR]