ABSTRACT
In recent decades, the demand for clean and renewable energy has grown increasingly urgent due to the irreversible alteration of the global climate change. As a result, organic solar cells (OSCs) have emerged as a promising alternative to address this issue. In this review, we summarize the recent progress in the molecular design strategies of benzodithiophene (BDT)-based polymer and small molecule donor materials since their birth, focusing on the development of main-chain engineering, side-chain engineering and other unique molecular design paths. Up to now, the state-of-the-art power conversion efficiency (PCE) of binary OSCs prepared by BDT-based donor materials has approached 20%. This work discusses the potential relationship between the molecular changes of donor materials and photoelectric performance in corresponding OSC devices in detail, thereby presenting a rational molecular design guidance for stable and efficient donor materials in future.
ABSTRACT
Neuroinflammation, marked by the release of pro-inflammatory cytokines and resulting neuronal death, is a multifaceted process extending beyond traditional inflammatory pathways. Microglia, primary cells in the inflammatory response, rapidly activate during neuroinflammation and produce pro-inflammatory and cytotoxic factors that affect neuronal function. Recent evidence highlights the significant role of abnormal lipid droplet (LD) deposition in the pathogenesis of neuroinflammation. While microglia are known to influence LD aggregation during neuroinflammation, the regulatory mechanism within neurons is not well understood. Our study demonstrates that lipopolysaccharide (LPS)-activated microglia induce the accumulation of LD in neurons, identifying microglial-derived lactic acid as a key mediator in this process. Excessive lipid accumulation threatens neuronal function, a phenomenon reversed by eliminating microglia. These findings, corroborated in both in vitro and in vivo settings and supported by RNA sequencing, deepen our understanding of neuronal lipid metabolism and suggest potential targets for therapeutic strategies against acute neuroinflammation.
ABSTRACT
Flexible perovskite solar cells (f-PSCs) have emerged as potential candidates for specific mechanical applications owing to their high foldability, efficiency, and portability. However, the power conversion efficiency (PCE) of f-PSC remains limited by the inferior contact between perovskite and flexible buried substrate. Here, an asymmetric π-extended self-assembled monolayer (SAM) (4-(9H-dibenzo[a,c]carbazol-9-yl)butyl)phosphonic acid (A-4PADCB) is reported as a buried substrate for efficient inverted f-PSCs. Employing this design strategy, A-4PADCB exhibits a significant orientation angle away from the surface normal, homogenizing the distribution of contact potentials. This enhancement improves the SAM/perovskite interface quality, controlling the growth of favorable perovskite films with low defect density and slight tensile stress. Integration of A-4PADCB into small-area f-PSCs and large-area flexible perovskite solar modules with an aperture area of 20.84 cm2 achieves impressive PCEs of up to 25.05% and 20.64% (certified 19.51%), respectively. Moreover, these optimized A-4PADCB-based f-PSCs possess enhanced light, thermal, and mechanical stability. This research paves a promising avenue toward the design of SAM-buried substrates with a large orientation angle, regulating perovskite growth, and promoting the commercialization of large-area flexible perovskite photovoltaics.
ABSTRACT
Herein, we propose a regional functionalization molecular design strategy that enables independent control of distinct pivotal parameters through different molecule segments. Three novel multiple resonances thermally activated delayed fluorescence (MR-TADF) emitters A-BN, DA-BN, and A-DBN, have been successfully synthesized by integrating highly rigid and three-dimensional adamantane-containing spirofluorene units into the MR framework. These molecules form two distinctive functional parts: partâ 1 comprises a boron-nitrogen (BN)-MR framework with adjacent benzene and fluorene units forming a central luminescent core characterized by an exceptionally rigid planar geometry, allowing for narrow FWHM values; partâ 2 includes peripheral mesitylene, benzene, and adamantyl groups, creating a unique three-dimensional "umbrella-like" conformation to mitigate intermolecular interactions and suppress exciton annihilation. The resulting A-BN, DA-BN, and A-DBN exhibit remarkably narrow FWHM values ranging from 18 to 14â nm and near-unity photoluminescence quantum yields. Particularly, OLEDs based on DA-BN and A-DBN demonstrate outstanding efficiencies of 35.0 % and 34.3 %, with FWHM values as low as 22â nm and 25â nm, respectively, effectively accomplishing the integration of high color purity and high device performance.
ABSTRACT
To effectively compete with the quenching process in long-wavelength regions like deep red (DR) and near-infrared (NIR), rapid radiative decay is urgently needed to address the challenges posed by the "energy gap law". Herein, we confirmed that it is crucial for hot exciton emitters to attain a narrow energy gap (ΔES1-T2) between the lowest singlet excited (S1) state and second triplet excited (T2) state, while ensuring that T2 slightly exceeds S1 in the energy level. Two proofs-of-concept of hot exciton DR emitters, namely αT-IPD and ßT-IPD, were successfully designed and synthesized by coupling electron-acceptors N,N-diphenylnaphthalen-2-amine (αTPA) and N,N-diphenylnaphthalen-1-amine (ßTPA) with an electron-withdrawing unit 5-(4-(tert-butyl) phenyl)-5H-pyrazino[2,3-b]indole-2,3-dicarbonitrile (IPD). Both emitters exhibited a narrow ΔES1-T2, with T2 being slightly higher than S1. Additionally, both emitters showed significantly large ΔET2-T1. Moreover, due to their aggregation-induced emission characteristics, J-aggregated packing modes, moderate strength intermolecular CNâ¯H-C and C-Hâ¯π interactions, and unique, comparatively large center-to-center distances among trimers in the crystalline state, both αT-IPD and ßT-IPD emitters exhibited remarkable photoluminescence quantum yields of 68.5% and 73.5%, respectively, in non-doped films. Remarkably, the corresponding non-doped DR-OLED based on ßT-IPD achieved a maximum external quantum efficiency of 15.5% at an emission peak wavelength of 667 nm, representing the highest reported value for hot exciton DR-OLEDs.
ABSTRACT
Organic solar cells, as a cutting-edge sustainable renewable energy technology, possess a myriad of potential applications, while the bottleneck problem of less than 20% efficiency limits the further development. Simultaneously achieving an ordered molecular arrangement, appropriate crystalline domain size, and reduced nonradiative recombination poses a significant challenge and is pivotal for overcoming efficiency limitations. This study employs a dual strategy involving the development of a novel acceptor and ternary blending to address this challenge. A novel non-fullerene acceptor, SMA, characterized by a highly ordered arrangement and high lowest unoccupied molecular orbital energy level, is synthesized. By incorporating SMA as a guest acceptor in the PM6:BTP-eC9 system, it is observed that SMA staggered the liquid-solid transition of donor and acceptor, facilitating acceptor crystallization and ordering while maintaining a suitable domain size. Furthermore, SMA optimized the vertical morphology and reduced bimolecular recombination. As a result, the ternary device achieved a champion efficiency of 20.22%, accompanied by increased voltage, short-circuit current density, and fill factor. Notably, a stabilized efficiency of 18.42% is attained for flexible devices. This study underscores the significant potential of a synergistic approach integrating acceptor material innovation and ternary blending techniques for optimizing bulk heterojunction morphology and photovoltaic performance.
ABSTRACT
Nonradiative recombination losses occurring at the interface pose a significant obstacle to achieve high-efficiency perovskite solar cells (PSCs), particularly in inverted PSCs. Passivating surface defects using molecules with different functional groups represents one of the key strategies for enhancing PSCs efficiency. However, a lack of insight into the passivation orientation of molecules on the surface is a challenge for rational molecular design. In this study, aminothiol hydrochlorides with different alkyl chains but identical electron-donating (-SH) and electron-withdrawing (-NH3 +) groups were employed to investigate the interplay between molecular structure, orientation, and interaction on perovskite surface. The 2-Aminoethane-1-thiol hydrochloride with shorter alkyl chains exhibited a preference of parallel orientations, which facilitating stronger interactions with the surface defects through strong coordination and hydrogen bonding. The resultant perovskite films following defect passivation demonstrate reduced ion migration, inhibition of nonradiative recombination, and more n-type characteristics for efficient electron transfer. Consequently, an impressive power conversion efficiency of 25 % was achieved, maintaining 95 % of its initial efficiency after 500â hours of continuous maximum power point tracking.
ABSTRACT
In the fabrication of inverted perovskite solar cells (PSCs), the wettability, adsorbability, and compactness of self-assembled monolayers (SAMs) on conductive substrates have critical impacts on the quality of the perovskite films and the defects at the buried perovskite-substrate interface, which control the efficiency and stability of the devices. Herein, three bisphosphonate-anchored indolocarbazole (IDCz)-derived SAMs, IDCz-1, IDCz-2, and IDCz-3, are designed and synthesized by modulating the position of the two nitrogen atoms of the IDCz unit to improve the molecular dipole moments and strengthen the π-π interactions. Regulating the work functions (WF) of FTO electrodes through molecular dipole moments and energy levels, the perovskite band bends upwards with a small offset for ITO/IDCz-3/perovskite, thereby promoting hole extraction and blocking electrons. As a result, the inverted PSC employing IDCz-3 as hole-collecting layer exhibits a champion PCE of 25.15%, which is a record efficiency for the multipodal SAMs-based PSCs. Moreover, the unencapsulated device with IDCz-3 can be stored for at least 1800 h with little degradation in performance.
ABSTRACT
Stretchable organic photovoltaics (OPVs) have attracted significant attention as promising power sources for wearable electronic systems owing to their superior robustness under repetitive tensile strains and their good compatibility. However, reconciling a high power-conversion efficiency and a reasonable flexibility is a tremendous challenge. In addition, the development of stretchable OPVs must be accelerated to satisfy the increasing requirements of niche markets for mechanical robustness. Stretchable OPV devices can be classified as either structurally or intrinsically stretchable. This work reviews recent advances in stretchable OPVs, including the design of mechanically robust transparent electrodes, photovoltaic materials, and devices. Initially, an overview of the characteristics and recent research progress in the areas of structurally and intrinsically stretchable OPVs is provided. Subsequently, research into flexible and stretchable transparent electrodes that directly affect the performances of stretchable OPVs is summarized and analyzed. Overall, this review aims to provide an in-depth understanding of the intrinsic properties of highly efficient and deformable active materials, while also emphasizing advanced strategies for simultaneously improving the photovoltaic performance and mechanical flexibility of the active layer, including material design, multi-component settings, and structural optimization.
ABSTRACT
Multi-component copolymerized donors (MCDs) have gained significant interest and have been rapidly developed in flexible organic solar cells (f-OSCs) in recent years. However, ensuring the power conversion efficiency (PCE) of f-OSCs while retaining ideal mechanical properties remains an enormous challenge. The fracture strain (FS) value of typical high-efficiency blend films is generally less than 8 %, which is far from the application standards of wearable photovoltaic devices. Therefore, we developed a series of novel MCDs after meticulous molecular design. Among them, the consistent MCD backbone and end-capped functional group formed a highly conjugated molecular plane, and the solubilization and mechanical properties were effectively optimized by modifying the proportion of solubilized alkyl chains. Consequently, due to the formation of entangled structures with a frozen blend film morphology considerably improved the high ductility of the active layer, P10.8/P20.2-TCl exhibited efficient PCE in rigid (18.53 %) and flexible (17.03 %) OSCs, along with excellent FS values (16.59 %) in pristine films, meanwhile, the outstanding FS values of 25.18 % and 12.3 % were achieved by P10.6/P20.4-TCl -based pristine and blend films, respectively, which were one of the highest records achieved by end-capped MCD-based binary OSCs, demonstrating promising application to synchronize the realization of high-efficiency and mechanically ductile flexible OSCs.
ABSTRACT
Despite rapid advancements in the photovoltaic efficiencies of perovskite solar cells (PSCs), their operational stability remains a significant challenge for commercialization. This instability mainly arises from light-induced halide ion migration and subsequent oxidation into iodine (I2). The situation is exacerbated when considering the heat effects at elevated temperatures, leading to the volatilization of I2 and resulting in irreversible device degradation. Mercaptoethylammonium iodide (ESAI) is thus incorporated into perovskite as an additive to inhibit the oxidation of iodide anion (I-) and the light-induced degradation pathway of FAPbI3âFAI+PbI2. Additionally, the formation of a thiol-disulfide/I--I2 redox pair within the perovskite film provides a dynamic mechanism for the continuous reduction of I2 under light and thermal stresses, facilitating the healing of iodine-induced degradations. This approach significantly enhances the operational stability of PSCs. Under the ISOS-L-3 testing protocol (maximum power point (MPP) tracking in an environment with relative humidity of ≈50% at ≈65 °C), the treated PSCs maintain 97% of their original power conversion efficieney (PCE) after 300 h of aging. In contrast, control devices exhibit almost complete degradation, primarily due to rapid thermal-induced I2 volatilization. These results demonstrate a promising strategy to overcome critical stability challenges in PSCs, particularly in scenarios involving thermal effects.
ABSTRACT
This study presents experimental evidence of the dependence of non-radiative recombination processes on the electron-phonon coupling of perovskite in perovskite solar cells (PSCs). Via A-site cation engineering, a weaker electron-phonon coupling in perovskite has been achieved by introducing the structurally soft cyclohexane methylamine (CMA+) cation, which could serve as a damper to alleviate the mechanical stress caused by lattice oscillations, compared to the rigid phenethyl methylamine (PEA+) analog. It demonstrates a significantly lower non-radiative recombination rate, even though the two types of bulky cations have similar chemical passivation effects on perovskite, which might be explained by the suppressed carrier capture process and improved lattice geometry relaxation. The resulting PSCs achieve an exceptional power conversion efficiency (PCE) of 25.5% with a record-high open-circuit voltage (VOC) of 1.20 V for narrow bandgap perovskite (FAPbI3). The established correlations between electron-phonon coupling and non-radiative decay provide design and screening criteria for more effective passivators for highly efficient PSCs approaching the Shockley-Queisser limit.
ABSTRACT
The ternary strategy, in which one guest component is introduced into one host binary system, is considered to be one of the most effective ways to realize high-efficiency organic solar cells (OSCs). To date, there is no efficient method to predict the effectiveness of guest components in ternary OSCs. Herein, three guest compositions (i.e., ANF-1, ANF-2 and ANF-3) with different electrostatic potential (ESP) are designed and synthesized by modulating the electron-withdrawing ability of the terminal groups through density functional theory simulations. The effects of the introduction of guest component into the host system (D18:N3) on the photovoltaic properties are investigated. The theoretical and experimental studies provide a key rule for guest acceptor in ternary OSCs to improve the open-circuit voltage, that is, the larger ESP difference between the guest and host acceptor, the stronger the intermolecular interactions and the higher the miscibility, which improves the luminescent efficiency of the blend film and the electroluminescence quantum yield (EQEEL) of the device by reducing the aggregation-caused-quenching, thereby effectively decreasing the non-radiative voltage loss of ternary OSCs. This work will greatly contribute to the development of highly efficient guest components, thereby promoting the rapid breakthrough of the 20% efficiency bottleneck for single-junction OSCs.
ABSTRACT
The hole-transporting material (HTM), poly (3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), is the most widely used material in the realization of high-efficiency organic solar cells (OSCs). However, the stability of PEDOT : PSS-based OSCs is quite poor, arising from its strong acidity and hygroscopicity. In addition, PEDOT : PSS has an absorption in the infrared region and high highest occupied molecular orbital (HOMO) energy level, thus limiting the enhancement of short-circuit current density (Jsc) and open-circuit voltage (Voc), respectively. Herein, two asymmetric self-assembled molecules (SAMs), namely BrCz and BrBACz, were designed and synthesized as HTM in binary OSCs based on the well-known system of PM6 : Y6, PM6 : eC9, PM6 : L8-BO, and D18 : eC9. Compared with BrCz, BrBACz shows larger dipole moment, deeper work function and lower surface energy. Moreover, BrBACz not only enhances photon harvesting in the active layer, but also minimizes voltage losses as well as improves interface charge extraction/ transport. Consequently, the PM6 : eC9-based binary OSC using BrBACz as HTM exhibits a champion efficiency of 19.70 % with a remarkable Jsc of 29.20â mA cm-2 and a Voc of 0.856â V, which is a record efficiency for binary OSCs so far. In addition, the unencapsulated device maintains 95.0 % of its original efficiency after 1,000â hours of storage at air ambient, indicating excellent long-term stability.
ABSTRACT
Microbial biotransformation is a recommended and reliable method in face of formidable tetracycline (TC) with broad-spectrum antibacterial activity. Herein, comprehensive characteristics of a newfound strain and its molecular mechanism in process of TC bioremediation were involved in this study. Specifically, Serratia marcescens MSM2304 isolated from pig manure sludge grew well in presence of TC and achieved optimal removal efficiency of 61% under conditions of initial TC concentration of 10 mg/L, pH of 7.0, cell inoculation amount of 5%, and tryptone of 10 g/L as additional carbon. The pathways of biotransformation include EPS biosorption, cell surface biosorption and biodegradation, which enzymatic processes of biodegradation were occurred through TC adsorbed by biofilms was firstly broken down by extracellular enzymes and part of TC migrated towards biofilm interior and degraded by intracellular enzymes. Wherein extracellular polysaccharides in extracellular polymeric substances (EPS) from biofilm of strain MSM2304 mainly performed extracellular adsorption, and changes in position and intensity of CO, =CH and C-O-C/C-O of EPS possible further implied TC adsorption by it. Biodegradation accounting for 79.07% played a key role in TC biotransformation and could be fitted well by first-order model that manifesting rapid and thorough removal. Potential biodegradation pathway including demethylation, dihydroxylation, oxygenation, and ring opening possibly involved in TC disposal process of MSM2304, TC-degrading metabolites exhibited lower toxicity to indicator bacteria relative to parent TC. Whole genome sequencing as underlying molecular evidence revealed that TC resistance genes, dehydrogenases-encoding genes, monooxygenase-encoding genes, and methyltransferase-encoding genes of strain MSM2304 were positively related to TC biodegradation. Collectively, these results favored a theoretical evaluation for Serratia marcescens MSM2304 as a promising TC-control agent in environmental bioremediation processes.
Subject(s)
Serratia marcescens , Tetracycline , Animals , Swine , Serratia marcescens/genetics , Anti-Bacterial Agents/analysis , Biotransformation , GenomicsABSTRACT
Organic solar cells (OSCs) with high performance were prepared using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and [2-(3,6-dibromo-9H-carbazol-9-yl)ethyl]phosphonic acid (Br-2PACz) double-layer films as the anode interface. By spin-coating a layer of Br-2PACz on PEDOT:PSS to form a PEDOT:PSS/Br-2PACz dual-anode interface, both the Jsc and FF of the device can be increased simultaneously, resulting in a high Jsc of 27.84 mA cm-2 and a high FF of 78.18%. The promising result indicates that the PEDOT:PSS/Br-2PACz dual-anode interface is an effective way to improve the performance of OSCs. The improvement of device performance is mainly attributed to (1) improved interface conductivity; (2) increased hole mobility and more balanced carrier transport efficiency; and (3) optimized morphology, which well explains the increase of Jsc and FF of the device. In addition, the OSC based on the PEDOT:PSS/Br-2PACz dual-anode interface exhibits exceptional stability, as it can maintain 94.7% of its initial efficiency even after 500 h of storage in a nitrogen environment. This work provides a promising strategy for improving the efficiency and stability of OSCs by dual-anode interface modulation.
ABSTRACT
The main obstacles to promoting the commercialization of perovskite solar cells (PSCs) include their record power conversion efficiency (PCE), which still remains below the Shockley-Queisser limit, and poor long-term stability, attributable to crystallographic defects in perovskite films and open-circuit voltage (Voc) loss in devices. In this study, potassium (4-tert-butoxycarbonylpiperazin-1-yl) methyl trifluoroborate (PTFBK) was employed as a multifunctional additive to target and modulate bulk perovskite defects and carrier dynamics of PSCs. Apart from simultaneously passivating anionic and cationic defects, PTFBK could also optimize the energy-level alignment of devices and weaken the interaction between carriers and longitudinal optical phonons, resulting in a carrier lifetime of greater than 3â µs. Furthermore, it inhibited non-radiative recombination and improved the crystallization capacity in the target perovskite film. Hence, the target rigid and flexible p-i-n PSCs yielded champion PCEs of 24.99 % and 23.48 %, respectively. More importantly, due to hydrogen bonding between formamidinium and fluorine, the target devices exhibited remarkable thermal, humidity, and operational tracking at maximum power point stabilities. The reduced Young's modulus and residual stress in the perovskite layer also provided excellent bending stability for flexible target devices.
ABSTRACT
Targeted treatment of the interface between electron transport layers (ETL) and perovskite layers is highly desirable for achieving passivating effects and suppressing carrier nonradiative recombination, leading to high performance and long-term stability in perovskite solar cells (PSCs). In this study, a series of non-fullerene acceptors (NFAs, Y-H, Y-F, and Y-Cl) are introduced to optimize the properties of the perovskite/ETL interface. This optimization involves passivating Pb2+ defects, releasing stress, and modulating carrier dynamics through interactions with the perovskite. Remarkably, after modifying with NFAs, the absorption range of perovskite films into the near-infrared region is extended. As expected, Y-F, with the largest electrostatic potential, facilitates the strongest interaction between the perovskite and its functional groups. Consequently, champion power conversion efficiencies of 21.17%, 22.21%, 23.25%, and 22.31% are achieved for control, Y-H-, Y-F-, and Y-Cl-based FA0.88Cs0.12PbI2.64Br0.36 (FACs) devices, respectively. This treatment also enhances the heat stability and air stability of the corresponding devices. Additionally, these modifier layers are applied to enhance the efficiency of Cs0.05(FA0.95MA0.05)0.95PbI2.64Br0.36 (FAMA) devices. Notably, a champion PCE exceeding 24% is achieved in the Y-F-based FAMA device. Therefore, this study provides a facile and effective approach to target the interface, thereby improving the efficiency and stability of PSCs.
ABSTRACT
Organic solar cells (OSCs) have attracted a great deal of attention in the field of clean solar energy due to their advantages of transparency, flexibility, low cost and light weight. Introducing them to the market enables seamless integration into buildings and windows, while also supporting wearable, portable electronics and internet-of-things (IoT) devices. With the development of photovoltaic materials and the optimization of fabrication technology, the power conversion efficiencies (PCEs) of OSCs have rapidly improved and now exceed 20%. However, there is a significant lack of focus on material stability and device lifetime, causing a severe hindrance to commercial applications. In this review, we carefully review important strategies employed to improve the stability of OSCs over the past three years from the perspectives of material design and device engineering. Furthermore, we analyze and discuss the current important progress in terms of air, light, thermal and mechanical stability. Finally, we propose the future research directions to overcome the challenges in achieving highly stable OSCs. We expect that this review will contribute to solving the stability problem of OSCs, eventually paving the way for commercial applications in the near future.
ABSTRACT
End-groups halogenation strategies, generally refers to fluorination and chlorination, have been confirmed as simple and efficient methods to regulate the photoelectric performance of non-fullerene acceptors (NFAs), but a controversy over which one is better has existed for a long time. Here, two novel NFAs, C9N3-4F and C9N3-4Cl, featured with different end-groups were successfully synthesized and blended with two renowned donors, D18 and PM6, featured with different electron-withdrawing units. Detailed theoretical calculations and morphology characterizations of the interface structures indicate NFAs based on different end-groups possess different binding energy and miscibility with donors, which shows an obvious influence on phase-separation morphology, charge transport behavior and device performance. After verified by other three pairs of reported NFAs, a universal conclusion obtained as the devices based on D18 with fluorination-end-groups-based NFAs and PM6 with chlorination-end-groups-based NFAs generally show excellent efficiencies, high fill factors and stability. Finally, the devices based on D18: C9N3-4F and PM6: C9N3-4Cl yield outstanding efficiency of 18.53 % and 18.00 %, respectively. Suitably selecting donor and regulating donor/acceptor interface can accurately present the photoelectric conversion ability of a novel NFAs, which points out the way for further molecular design and selection for high-performance and stable organic solar cells.