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The cathode interface layers (CILs) play a crucial role in enhancing the performance of organic solar cells (OSCs). However, challenges arise due to the high work function of CIL and inadequate contact with the active layer, leading to high interface trap recombination and poor charge extraction. In this study, a novel approach is proposed to improve charge injection and extraction in CILs by incorporating polyphenols, trihydroxybenzoic acid (TBA). Focusing on the CIL PDINN, its work function is successfully reduced from 4.14 eV to 3.80 eV and obtained charge collection efficiency of 91.23% through TBA regulation. These enhancements can be ascribed to improved contact between the active layer and the CILs, and enhanced the formation of a fine fiber phase width and inhibited interface recombination. As a result, the power conversion efficiency (PCE) of the binary OSCs comprising PM6: BTP‐ec9 exhibits an increase from 18.2% to 19.3%, placing it among the one of the highest PCE values. Moreover, this approach demonstrated notable applicability for another CILs, as well as various OSCs systems. Overall, this research underscores the importance of regulating and modifying CILs to fully exploit their potential in OSCs devices, while laying the groundwork for optimizing their efficiency and stability. [ABSTRACT FROM AUTHOR]

Asymmetric perylene diimide (PDI)-based dimeric electron acceptors have received relatively little attention. Herein, two asymmetric fused PDI dimers, namely PDI-TPDI and PDI-SePDI, linked through one single bond (σ bond), were synthesized by S/Se-annulation at the outside bay position. Both of them exhibited outstanding thermal-stability with a 5% decomposition temperature of higher than 400 °C and good photostability. After replacing S-annulation with Se-annulation, a blue-shifted absorption peak, weakened aggregation, deepened ELUMO, but almost unchanged molecular twisting angle between two aromatic rings were observed. Accordingly, the Se-annulated PDI-SePDI-based device achieved a 56.64% elevated PCE as high as 5.31% with a slightly decreased VOC of 0.70 V, a 55.91% increased JSC of 14.64 mA cm−2, a 3.45% enhanced FF of 51.84%, and the S-annulated PDI-TPDI-based device obtained the PCE of 3.39%. The PCE enhancement was mainly due to the enhanced exciton dissociation, suppressed charge recombination, and increased charge mobility, benefiting from the beneficial microstructural morphology as the result of larger heteroatom Se-annulation. This work revealed the regulating mechanism of Se-annulation of PDI at the outside position on molecular distortion, morphology and photovoltaic performance. [ABSTRACT FROM AUTHOR]

Chlorination is considered an appealing strategy aimed at improving the optoelectronic properties, reducing aggregation and thus enhancing device performance due to a low synthetic cost, a large C–Cl dipole moment and high π-electron delocalization originating from an empty 3d orbital. To broaden the structural multiplicity of chlorinated conjugated polymers (CPs), herein, three monochlorinated benzothiadiazole-based medium bandgap (MBG) polymer donors, PClBDT-ClBT, PClBDT-TClBT, and PClBDT-DTClBT, were developed by varying the octylthiophene π bridge number between chlorinated benzo[1,2-b:4,5-b′]dithiophene (ClBDT) and 5-chlorobenzo[c][1,2,5]thiadiazole (ClBT). Increasing the octylthiophene π bridge number led to a blue-shifted maximum absorption peak, a reduced bandgap, a slightly elevated absorption coefficient, raised EHOMO, weakened molecular aggregation and a dominant face-on molecular orientation. As expected, importing an octylthiophene π bridge impaired the VOC but gave rise to a suitable microstructural morphology, appropriate miscibility and an improved photophysical process. Therefore, the PClBDT-ClBT-based device exhibited a low PCE of only 1.42%, limited by low JSC and FF. Meanwhile, the PClBDT-TClBT-based device afforded a VOC of 0.87 V, a JSC of 22.45 mA cm−2, and a FF of 59.21% when paired with Y6, collectively contributing to the outstanding PCE as high as 11.52%. However, the PClBDT-DTClBT-based device gave a decreased VOC of 0.81 V and a JSC of 18.57 mA cm−2, but a higher FF of 62.99%, resulting in a decreased PCE of 9.48%. To the best of our knowledge, 11.52% efficiency is the highest PCE recorded among those of the chlorinated BT-based CPs in binary organic solar cells so far. Our findings facilitate a better understanding of the structure–property–performance relationship for precisely tuning the conjugated π bridge which could effectively affect the energy level, microstructure, photophysical procedure, and thus boost the photovoltaic performance. [ABSTRACT FROM AUTHOR]

2D hybrid perovskites have emerged as a promising alternative material to address the environmental stability and the ion‐migration of the 3D perovskites for direct X‐ray detector applications. Nevertheless, the X‐ray detection performance of the 2D hybrid perovskites still lags because of its low X‐ray attenuation ability and limited solubility for thick film deposition. Here, a high‐performance X‐ray detector in Dion‐Jacobson 2D hybrid perovskite, 2(aminomethyl) pyridinium lead bromide (2AMPPbBr4), is studied. 2AMPPbBr4 exhibits an ultra‐short interlayer distance of 3.43 Å, leading to high X‐ray attenuation ability. Furthermore, DFT results indicate that 2AMPPbBr4 exhibits type II band alignment between 2AMP2+ ligand and the [PbI6]4− layers, facilitating effective spatial separation of photo‐generated carriers. The X‐ray detector made of 2AMPPbBr4 with an average thickness of 200 µm is realized via an improved drop‐casting method. An improved X‐ray sensitivity of 3933.88 µC Gy−1 cm−2 and a low detection limit of 4.17 nGy s−1 is achieved. This work paves the way for high‐performance X‐ray detectors based on the emerging 2D perovskite materials. [ABSTRACT FROM AUTHOR]

Halogenation of Y‐series small‐molecule acceptors (Y‐SMAs) is identified as an effective strategy to optimize photoelectric properties for achieving improved power‐conversion‐efficiencies (PCEs) in binary organic solar cells (OSCs). However, the effect of different halogenation in the 2D‐structured large π‐fused core of guest Y‐SMAs on ternary OSCs has not yet been systematically studied. Herein, four 2D‐conjugated Y‐SMAs (X‐QTP‐4F, including halogen‐free H‐QTP‐4F, chlorinated Cl‐QTP‐4F, brominated Br‐QTP‐4F, and iodinated I‐QTP‐4F) by attaching different halogens into 2D‐conjugation extended dibenzo[f,h]quinoxaline core are developed. Among these X‐QTP‐4F, Cl‐QTP‐4F has a higher absorption coefficient, optimized molecular crystallinity and packing, suitable cascade energy levels, and complementary absorption with PM6:L8‐BO host. Moreover, among ternary PM6:L8‐BO:X‐QTP‐4F blends, PM6:L8‐BO:Cl‐QTP‐4F obtains a more uniform and size‐suitable fibrillary network morphology, improved molecular crystallinity and packing, as well as optimized vertical phase distribution, thus boosting charge generation, transport, extraction, and suppressing energy loss of OSCs. Consequently, the PM6:L8‐BO:Cl‐QTP‐4F‐based OSCs achieve a 19.0% efficiency, which is among the state‐of‐the‐art OSCs based on 2D‐conjugated Y‐SMAs and superior to these devices based on PM6:L8‐BO host (17.70%) and with guests of H‐QTP‐4F (18.23%), Br‐QTP‐4F (18.39%), and I‐QTP‐4F (17.62%). The work indicates that halogenation in 2D‐structured dibenzo[f,h]quinoxaline core of Y‐SMAs guests is a promising strategy to gain efficient ternary OSCs. [ABSTRACT FROM AUTHOR]

Nonlinear optical limiting (OL) properties of carboxyl-functionalized Ti3C2 nanosheets (COOH-MXene) were studied using the nanosecond laser Z-scan technology. COOH-MXene showed excellent broadband OL properties with OL thresholds of 0.34 J/cm2 at 532 nm and 0.58 J/cm2 at 1064 nm, and the OL mechanism was mainly attributed to the reverse saturable absorption effect. Femtosecond time-resolved transient absorption measurements were used to clarify the ultrafast carrier dynamics in the OL process, and the results revealed that excited states absorption (ESA) in MXene was enhanced by introducing more carboxyl group terminations. When COOH-MXene was irradiated by laser pulses, excited electrons in the conduction band of MXene could transfer to the carboxyl groups and induce the ESA in the surface functional groups, resulting in the excellent OL property of COOH-MXene. [ABSTRACT FROM AUTHOR]

L-Glutathione reduced (GSH) is a small molecule peptide found in large quantities in living organisms, particularly in animal liver cells. Its unique structure gives it great potential to act as an environmentally friendly and efficient corrosion inhibitor. The inhibition properties of GSH for mild steel in simulated concrete pore solutions (SCPS) containing chlorine was investigated by electrochemical tests and SEM-EDS surface analysis. According to the experimental results, GSH mainly blocked the cathodic corrosion reaction and has a corrosion inhibition efficiency of up to 92.3% at room temperature, enhancing the corrosion resistance of mild steel. The isothermal adsorption results indicate that the adsorption behavior of GSH on the surface follows the Langmuir isothermal adsorption model. Both quantum chemical calculations (QC) and molecular dynamics simulations (MD) show that GSH can be effectively adsorbed onto mild steel substrates, thus protecting the surface from erosion. Finally, the results of the above experiments and theoretical calculations are combined to elucidate the inhibitive mechanism: GSH molecules binds to the iron surface via the sulfur, nitrogen and oxygen atoms in the molecule, thus adsorbing to the iron surface in a tiled manner and forming a protective film to prevent the corrosive material from contacting the iron surface. [ABSTRACT FROM AUTHOR]

Controlled sequential crystallization of donors and acceptors is a critical factor for achieving enhanced phase separation and efficient charge transfer performance in polymer solar cells (PSCs). In this study, a comprehensive investigation of a structurally simple solvent additive, 1‐fluoro‐2‐iodobenzene (OFIB) is conducted, which efficiently controls the morphology of the active layer, resulting in fibrous assembly and significantly enhancing the power conversion efficiency from 16.34% to 18.38% based on the PM6:L8‐BO system. Density functional theory, molecular dynamics simulations, and grazing incidence small‐ and wide‐angle X‐ray scattering techniques reveal that the addition of OFIB to the processed blend aligns the orientation of the acceptor molecules, thereby enhancing the overall π–π stacking in the active layer. OFIB establishes nearly equal‐strength π–π interactions with the conjugated frameworks of both the donor and acceptor materials, benefiting from the multiple electron conjugation between its iodine atom and the conjugated framework in the active layer. Femtosecond‐timescale photophysical studies demonstrate that the OFIB‐optimized active layer shows reduced exciton losses at the donor–acceptor interface. This study offers a new perspective on the mechanism underlying the function of solvent additives and presents a comprehensive research methodology that will guide the development of next‐generation non‐fullerene acceptors for efficient PSCs. [ABSTRACT FROM AUTHOR]

The nonlinear optical limiting (OL) property of tin phthalocyanine porous organic frameworks (Sn-Pc-POFs) dispersion in the nanosecond regime was studied, which showed excellent dispersibility and stability as well as a low OL threshold. To clarify the nonlinear optical response mechanisms in the material, the energy level structure of Sn-Pc-POFs was simulated using the density functional theory calculation, and the photoinduced carrier dynamics was studied using femtosecond time-resolved transient absorption spectroscopy. The results indicated that the large absorption cross section and long lifetime of the excited state were responsible for the excellent OL property of the material. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) process fascinating solution‐printing capability to achieve low‐cost and large‐scale manufacture. However, the rapid power conversion efficiency (PCE) decay with active layer thickness enlargement inhibits the implement of OSCs' potential advantages. To overcome the bottlenecks of PCE decay in thick active layer OSCs, the electrical doping with componential selectivity in bulk heterojunction (BHJ) film is achieved by introducing a solid solvation additive. Benefiting from the higher exciton splitting efficiency together with the longer drift (Ldr) and diffusion (Ldiff) lengths, an OSC with 100 nm BHJ film demonstrates a PCE increment from 16.44% to 18.24% with prolonged dark and illuminated storage stabilities. Applying the solid solvation assisted (SSA) doping method in the OSCs with 500 nm active layer, the PCE significantly increases by 31.9%, from the original value of 11.79% to 15.55%. It further improves to 15.84% in a ternary blend thick‐film device, which is the record value to the best of our knowledge. Besides, the SSA doping narrows the PCE gap between the 0.04 and 1 cm2 devices. All improvements demonstrate the great potential of SSA doping for OSC commercial manufacture, since it optimizes the photovoltaic performance under all practical conditions of long‐term, thick‐film, and large‐area. [ABSTRACT FROM AUTHOR]

Recently, perylene diimide (PDI)-based all-polymer solar cells (All-PSCs) have gained increasing attention due to molecular structural diversity, facile chemical modification, and mechanical and morphological stability. However, acceptor–acceptor (A–A)-structured PDI-based polymeric acceptors (PAs) exhibit inferior photovoltaic performance to donor–acceptor type and/or fused-PDI-based ones. Herein, two A–A type thermo- and photo-stable PAs, namely, PPDI-DTBT and PPDI-DTFBT, by choosing a long 2-octyldodecyl-substituted PDI unit and 4,7-dithienylbenzo[c][1,2,5]thiadiazole (DTBT) and/or partially fluorinated 4,7-dithienyl-5-fluorobenzo[c][1,2,5]thiadiazole (DTFBT) subunits to construct a polymer backbone, were developed. Both of them possess a complementary absorption profile and a similar ELUMO to donor PTB7-Th. Not only a slightly descended LUMO energy level, better molecular planarity and aggregation, and reduced exciton binding energy (Eb), but also enhanced exciton dissociation efficiency, more closed and ordered stacking, higher and balanced charge mobility and a desired microstructural morphology structure were achieved in partially fluorinated PPDI-DTFBT. Moreover, femtosecond transient absorption (fs-TA) spectra suggested faster and more efficient exciton dissociation and transfer characteristics in the PTB7-Th:PPDI-DTFBT system. These changes enabled the PPDI-DTFBT-based device to acquire a PCE of 6.04%, which was 51.76% higher than that (3.98%) of its counterpart. This increase was mainly profited from 32.70% increased JSC from 11.10 to 14.73 mA cm−2 and 13.92% enhanced FF from 46.54% to 53.02%. The current results demonstrate that precisely incorporating fluorine into an A–A type PDI-based polymer backbone can synergistically adjust the molecular aggregation and improve the photophysical process, with the aim of gaining an inspirational device efficiency in all-PSCs. [ABSTRACT FROM AUTHOR]