Search

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 solid additive strategy represents a simple yet effective approach to achieving high‐efficiency organic solar cells (OSCs) by enhancing the morphology of the active layer. In this study, a highly volatile solid additive, 2,4,6‐trichloro‐1,3,5‐triazine (TCT), is employed to modulate the morphology. Unlike other solid additives previously reported, TCT exhibits remarkable intermolecular interactions with both polymer donor and acceptor, offering two distinct advantages. Firstly, TCT notably enhances the crystallinity and molecular order of the blend film, subtly optimizing the fiber network structure within, thereby facilitating carrier transport and significantly improving the mobility of the blend film. Secondly, TCT stabilizes the bi‐continuous fibrous morphology of the polymer donor and acceptor, mitigating the morphological evolution of the active layer and enhancing device stability. Consequently, the D18:L8‐BO:TCT device exhibits a higher power conversion efficiency of 19.50% compared to the D18:L8‐BO device (18.13%). Furthermore, after 960 h of storage, the OSC device treated with TCT retains 90% of its initial PCE, significantly outperforming the D18:L8‐BO device (73%). This study presents a promising avenue for achieving high‐performance OSCs through manipulating the active layer morphology with solid additives. [ABSTRACT FROM AUTHOR]

Organic photovoltaics (OPVs) have made significant strides with efficiencies now exceeding 20%, positioning them as potential competitors to inorganic solar technologies. One of the most critical challenges toward this goal is the severe open‐circuit voltage (Voc) loss caused by the nonradiative charge recombination (NRCR). Herein, this review comprehensively summarizes the NRCR mechanisms and suppression techniques of OPVs across various scales from molecule to device. Specifically, the origins of NRCR in a single molecule are first summarized, and molecular design principles toward high photoluminescence quantum yield are reviewed following the Marcus theory. Next, the effect of aggregation on NRCR is reviewed, as well as the molecular and processing strategies to modulate the film packing for NRCR suppression. Furthermore, the progresses in the avoidance of nonradiative loss pathways mediated by charge transfer states and triplet states in donor:acceptor bulk heterojunctions are tracked. Besides, the interfacial optimization and device structure design to maximize the electroluminescent quantum efficiency are presented. Finally, several potential pathways toward curtailing NRCR for high‐performance OPVs are outlined. Therefore, this review shows an insightful perspective to understand and mitigate the NRCR at multi‐scales, and is poised to provide a clear roadmap for the next breakthrough of OPVs. [ABSTRACT FROM AUTHOR]

Context: Indandione-based materials are promising candidates for organic electronics, offering high electron mobility and tunable optoelectronic properties. In this study, we explore the optoelectronic and photovoltaic properties of indandione-based donor–acceptor (D-A) materials, specifically (R1) and (R2), by introducing malononitrile group acceptors into their molecular structure. These strong electron-withdrawing acceptors are designed to enhance charge transfer and overall material performance. The designed molecules (DM1–DM4) exhibit a low optical band gap of approximately 1.77 eV, significantly lower than the reference materials (R1 and R2) at around 2.24 eV in a solvent environment. Among the designed molecules, DM4 stands out with superior photovoltaic parameters, including a narrow optical band gap (1.77 eV), higher electron affinity (3.49 eV), an extended excited state lifetime (10.0 ns) owing to its low electron and hole reorganization energies (λe ~ 0.13 eV and λh ~ 0.24 eV), and improved short-circuit current density (Jsc) of ~ 15.73 mA/cm2. Notably, DM4 achieves a power conversion efficiency (PCE) of ~ 18.5%, making it an excellent candidate for device applications. Method: A comprehensive computational investigation was carried out on indandione-based D-A materials with malononitrile group acceptors (DM1–DM4) using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, as implemented in Gaussian 16 software. We examined the electronic and optical properties of the proposed molecules through frontier molecular orbital (FMO) analysis, UV–Vis absorption spectra, density of states (DOS), exciton binding energy (Eb), and transition density matrix (TDM) analysis, utilizing GaussView 6.0 and Multiwfn 3.8 software. The photovoltaic parameters and power conversion efficiency (PCE) were evaluated using the Scharber and Alharbi models. [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]

Copyright of Journal of Donghua University (Natural Science Edition) is the property of Journal of Donghua University (Natural Science) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structural revolutions of non‐fullerene acceptors (NFAs) have driven continuous efficiency breakthroughs in organic solar cells (OSCs). Rational regulation of NFA structures toward efficient exciton dissociation and mitigated non‐radiative recombination is pivotal for OSCs. The incorporation of asymmetric side chains on NFAs can often achieve these goals by inducing a desirable aggregate state. However, it lacks the studies to directly correlate the side‐chain symmetry of NFAs with the exciton delocalization and triplet dynamics in OSCs. Herein, The influence of structural symmetry on the aggregate properties is systematically investigated and exciton/charge dynamics based on two developed biaxial‐conjugated NFAs with varied side‐chain symmetry. The symmetric NFA having diverse molecular packing orientations can form multiple charge transfer channels in its blend with polymer donor, which cannot be found in that comprising the asymmetric ones. Moreover, a slower rate and lower ratio of the spin‐triplet state are formed in the blend of symmetric NFA, resulting in a much lower non‐radiative voltage loss in corresponding OSCs. This study reveals the distinct advantages of symmetric NFAs in both aggregate properties and exciton/charge dynamics over those of asymmetric ones, paving the way for developing high‐performance OSCs using easier‐to‐prepare, low‐cost symmetric materials. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The industrialization of organic solar cells (OSCs) faces challenges due to complex synthesis routes and high costs of organic photovoltaic materials. To address this, we designed and synthesized a series of polythiophene‐based donor materials, PTVT‐T‐xCl (20%Cl, 50%Cl and 100%Cl), by introducing different degrees of chlorine substitution within their conjugated skeletons. The incorporation of chlorine atoms does not change the planar conformation of the conjugated main chain of the control polymer, PTVT‐T, but effectively reduces their HOMO energy levels (≤ –5.3 eV) and alters the crystallinity of the polymers. In addition, when preparing OSC by blending with non‐fused electron acceptor A4T‐16, the non‐radiative energy loss of the three photovoltaic devices gradually decreased with the increase of chlorine content (0.343, 0.278 and 0.189 eV, respectively). Notably, PTVT‐T‐20%Cl exhibited a more moderate nanoscale phase separation with the acceptor, leading to efficient exciton dissociation, lower bimolecular recombination, and thus a favorable current in the OSCs. Consequently, the photovoltaic device based on PTVT‐T‐20%Cl:A4T‐16 achieved a remarkable photovoltaic efficiency of 11.8%. In addition, the PTVT‐T‐xCl series polymers show much lower material‐only‐cost (MOC) values than the other reported photoactive material systems. This work provides the way for the development of low‐cost photovoltaic materials and the industrial application of OSC, overcoming previous limitations posed by high energy losses in polythiophene‐based donors. [ABSTRACT FROM AUTHOR]

Polymeric hole transport materials (HTMs) have emerged because of their potential to produce dopant‐free, efficient, and stable perovskite solar cells (PSCs). Therefore, we engineered 10 novel donor materials (SMH1–SMH10) containing phenanthrocarbazole‐based polymeric structures for organic and PSCs. These molecules underwent bridging‐core modifications using different spacers, such as furan (N1), pyrrole (N2), benzene (N3), pyrazine (N4), dioxane (N5), isoxazole (N6), isoindole (N7), indolizine (N8), double bond (N9), and pyrimidine (N10), in comparison to reference molecule R. The study examined the structure–property relationship and the impact of these modifications on the optical, photovoltaic, photophysical, and optoelectronic characteristics of the newly designed SMH1–SMH10 series. Density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT) calculations were conducted to analyze frontier molecular orbitals, density of states, reorganization energies, open‐circuit voltage, transition density matrix, and charge transfer processes. Results show that the newly designed molecules (SMH1–SMH10) exhibited superior optoelectronics characteristics compared to the R molecule. Among these, SMH4 is the most promising candidate, with a small band gap (2.79 eV), low electron and hole mobility (λe 0.0028 eV, λh 0.0020 eV), lower binding energy (Eb 0.58 eV), high λmax values (656.42 nm in gas, 573.34 nm in chlorobenzene), and a high Voc of 1.30 V. Therefore, this study demonstrated that bridging‐core modifications offer a simple and effective strategy for designing desirable characteristics molecules for photovoltaic applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the continuous development of photovoltaic materials, organic solar cells (OSCs) have made remarkable advancements, surpassing a power conversion efficiency (PCE) of 20%. However, the PCEs of OSCs remain lower than that of inorganic solar cells due to significant energy losses, mainly stemming from the relatively large non‐radiative recombination losses (usually be expressed as ∆E3), resulting in low open‐circuit voltages. This can be achieved by reducing non‐radiative recombination, and hereby increasing the electroluminescence quantum efficiency (EQEEL) of the photo‐active layer. This review analyzes the significance of luminescence efficiency in achieving high‐performance OSCs by examining the reciprocal relationship between ∆E3 and EQEEL. High‐efficiency organic solar cells can also be used as effective organic light‐emitting diodes (OLEDs). The discussion provides insights into the influencing factors of EQEEL and the mechanisms for adjusting various parameters, which include enhancements in photoluminescence quantum yield and the proportion of radiative excitons. The objective is to offer insights into the crucial role of luminescence performance in OSC development, guiding researchers toward developing novel photovoltaic materials or optimization strategies to enhance the luminescence performance of the active layer in OSCs, fostering the simultaneous advancement of OSCs and OLEDs. Key Scientists: [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the continuous development of photovoltaic materials, organic solar cells (OSCs) have made remarkable advancements, surpassing a power conversion efficiency (PCE) of 20%. However, the PCEs of OSCs remain lower than that of inorganic solar cells due to significant energy losses, mainly stemming from the relatively large non‐radiative recombination losses (usually be expressed as ∆E3), resulting in low open‐circuit voltages. This can be achieved by reducing non‐radiative recombination, and hereby increasing the electroluminescence quantum efficiency (EQEEL) of the photo‐active layer. This review analyzes the significance of luminescence efficiency in achieving high‐performance OSCs by examining the reciprocal relationship between ∆E3 and EQEEL. High‐efficiency organic solar cells can also be used as effective organic light‐emitting diodes (OLEDs). The discussion provides insights into the influencing factors of EQEEL and the mechanisms for adjusting various parameters, which include enhancements in photoluminescence quantum yield and the proportion of radiative excitons. The objective is to offer insights into the crucial role of luminescence performance in OSC development, guiding researchers toward developing novel photovoltaic materials or optimization strategies to enhance the luminescence performance of the active layer in OSCs, fostering the simultaneous advancement of OSCs and OLEDs. Key Scientists: [ABSTRACT FROM AUTHOR]

Abstract Our research focuses on enhancing the broadband absorption capability of organic solar cells (OSCs) by integrating plasmonic nanostructures made of Titanium nitride (TiN). Traditional OSCs face limitations in absorption efficiency due to their thickness, but incorporating plasmonic nanostructures can extend the path length of light within the active material, thereby improving optical efficiency. In our study, we explore the use of refractory plasmonics, a novel type of nanostructure, with TiN as an example of a refractory metal. TiN offers high-quality localized surface plasmon resonance in the visible spectrum and is cost-effective, readily available, and compatible with CMOS technology. We conducted detailed numerical simulations to optimize the design of nanostructured OSCs, considering various shapes and sizes of nanoparticles within the active layer (PM6Y6). Our investigation focused on different TiN plasmonic nanostructures such as nanospheres, nanocubes, and nanocylinders, analyzing their absorption spectra in a polymer environment. We assessed the impact of their incorporation on the absorbed power and short-circuit current (Jsc) of the organic solar cell.

Non‐fullerene acceptors (NFAs) have demonstrated a great potential for the transcendence of performance limits in organic photovoltaics. Despite the tremendous efforts, however, synthetic control of non‐ideal recombination losses on the photovoltage are still elusive and thus lag far behind the inorganic counterparts. Here, a rational design strategy of non‐fullerene acceptors is presented to overcome the limitations derived from the inherent excited state properties of organic molecules. Spectroscopic studies on a series of chemical analogs of ladder‐type fused acceptors reveal that the radiative efficiency of non‐fullerene acceptors is predominantly determined by the inherently strong electron‐vibration coupling of their bound excited states, rather than the redistribution of molecular orbitals itself. In this sense, regardless of intramolecular charge transfer characteristics, the incorporation of rigid, and planar moiety with wide π plane is found to promote the dominance of long‐lived and weakly‐bound excited states in the photophysical process, in which the mitigated non‐radiative decays of NFAs can be directly translated into that of charge‐transfer states. Furthermore, the incorporation of such chemical moiety can minimize the evolution of subgap broadening in the bulk heterojunction blends, lowering the contribution of non‐ideal radiative losses. As a result, the model systems demonstrate the non‐radiative loss down to 180–190 meV, without sacrificing photocurrent generations, reaching that of inorganic counterparts. [ABSTRACT FROM AUTHOR]

In recent years, self‐assembled monolayers (SAMs) have been proven to work efficiently as hole‐selective materials in both organic solar cells (OSCs) and perovskite solar cells. Although competitive performances are reported with these materials, a mechanistic understanding on device stability remains elusive. This study reveals that while various SAM molecules can increase the indium tin oxide (ITO) work function versus vacuum, they may not consistently result in monolayers that ensure simultaneous improvement in performance and operational stability of devices. Energetically, achieving alignment between the work function of the SAM‐modified electrode and the ionization energy (IE) of the donor is shown to be crucial for a low hole injection barrier, irrespective of the SAM's IE. Light‐induced degradation in the widely used SAM, (2‐(9H‐carbazol‐9‐yl)ethyl) phosphonic acid (2PACz), is identified through diverse aging tests and comprehensive chemical and electronic characterizations. This degradation involves SAM molecule decomposition and chemical reactions with the photoactive layer, contributing further to device degradation. Addressing these challenges, sputtered nickel oxide/SAM bilayers are proposed as hole‐selective contact with tailored interface energetics for both efficient and photostable OSCs, offering a promising alternative to commonly used hygroscopic PEDOT:PSS in OSCs. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) are considered a very promising technology to convert solar energy to electricity and a feasible option for the energy market because of the advantages of light weight, flexibility, and roll-to-roll manufacturing. They are mainly characterized by a bulk heterojunction structure where a polymer donor is blended with an electron acceptor. Their performance is highly affected by the design of donor–acceptor conjugated polymers and the choice of suitable acceptor. In particular, benzotriazole, a typical electron-deficient penta-heterocycle, has been combined with various donors to provide wide bandgap donor polymers, which have received a great deal of attention with the development of non-fullerene acceptors (NFAs) because of their suitable matching to provide devices with relevant power conversion efficiency (PCE). Moreover, different benzotriazole-based polymers are gaining more and more interest because they are considered promising acceptors in OSCs. Since the development of a suitable method to choose generally a donor/acceptor material is a challenging issue, this review is meant to be useful especially for organic chemical scientists to understand all the progress achieved with benzotriazole-based polymers used as donors with NFAs and as acceptors with different donors in OSCs, in particular referring to the PCE. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

Solution‐processible organic solar cells (OSCs) have gained much attention as one of the most promising options for sustainable energy. With rapidly increasing efficiency of OSCs, developing small molecular acceptors (SMAs) with simple molecular structures are critical for reducing the cost of photovoltaics. Herein, three new SMAs (BZ4F‐C2SEH, BZ4F‐2C2SEH, BZ4F‐SEH) are designed by the incorporation of ethyl(2‐ethylhexyl)sulfane or (2‐ethylhexyl)‐sulfane at the β‐position of thiophene. As a result, the BZ4F‐C2SEH‐based devices obtained an optimal PCE of 15.08% with a good balance between open‐circuit voltage (Voc = 0.87 V) and short‐circuit current density (Jsc = 23.27 mA cm−2) by blending with low‐cost polymer donor PTQ10. Besides, the BZ4F‐C2SEH based devices treated by thermal annealing (TA) and solvent annealing (SVA) deliver a satisfactory power conversion efficiency (PCE) of 16.18% with a Voc of 0.88 V, and a Jsc of 23.98 mA cm−2. This work highlights that attaching asymmetric alkylthio side chain at the β‐position of thiophene can be used as an effective molecular design strategy to trade off Voc and Jsc, thus improving the photovoltaic performance of OSCs. [ABSTRACT FROM AUTHOR]

The achievement of high performance in organic solar cells (OSCs) is highly dependent on efficient exciton dissociation. However, a comprehensive understanding of the exciton dissociation process under photoexcitation in OSCs remains elusive. Herein, a prototypical system of PM6:Y6 is adopted to explore the exciton dissociation process. An organic semiconductor PCz with distinctive photoexcitation signals from PM6 and Y6 is incorporated as the third component. Femtosecond transient absorption spectroscopy demonstrates clear cascade charge transfer processes in ternary PM6:PCz:Y6 system. These cascade channels contribute to enhancing the efficiency of exciton dissociation. Consequently, the nonradiative recombination energy loss is reduced, resulting in an improved power conversion efficiency (PCE) of OSCs. Furthermore, the reduction of energy loss is verified in different OSCs. When PCz is introduced into the D18:L8‐BO system, a low nonradiative recombination energy loss of 0.175 eV is demonstrated, contributing a PCE of over 19%. This work highlights that the insight of efficient exciton dissociation enables low nonradiative recombination losses for efficient OSCs. [ABSTRACT FROM AUTHOR]

Semitransparent organic solar cells show attractive potential in the application of building‐integrated photovoltaics, agrivoltaics, floating photovoltaics, and wearable electronics, as their multiple functionalities of electric power generation, photopermeability, and color tunability. Design and exploration of semitransparent organic solar cells with optimal and balanced efficiency and average visible light transmittance and simultaneously high stability are in great demand. In this work, based on a layer‐by‐layer‐processed active layer and an ultrathin metal electrode, inverted semitransparent organic solar cells (ITO/AZO/PM6/BTP‐eC9/MoO3/Au/Ag) were fabricated. Optimal and balanced efficiency and average visible light transmittance were demonstrated, and simultaneously promising thermal and light stability were achieved for the obtained devices. The power conversion efficiency of 13.78–12.29% and corresponding average visible light transmittance of 14.58–25.80% were recorded for the ST‐OSC devices with 25–15 nm thick Ag electrodes, respectively. Superior thermal and light stability with ~90% and ~85% of initial efficiency retained in 400 h under 85 °C thermal stress and AM1.5 solar illumination were demonstrated, respectively. [ABSTRACT FROM AUTHOR]

Organic photovoltaic (OPV) technology has recently achieved remarkable progress in academia, attaining power conversion efficiencies exceeding 19%, a breakthrough previously unimaginable. Despite these advancements, the translation of high‐efficiency OPV cells into the commercialization of OPV modules has been limited, impeding the market penetration of OPV technology. Upon careful examination, various challenges emerge, including disparities between laboratory research and industrial production in device architecture, influenced by considerations of cost and manufacturability. Additionally, the incorporation of high‐efficiency materials requires careful consideration not only of the compatibility between the photoactive layer and interface layers or transparent electrodes but also of the associated synthetic complexity of chemical structures and cost implications. While these issues are crucial, they may not be widely discussed in current mainstream research. In this article, the purpose is to identify bottlenecks from a material techniques perspective, with the aim of promoting increased resources in the research of pertinent module technologies. This effort is intended to propel OPV technology toward greater success and bring it into closer alignment with the goals of commercialization. [ABSTRACT FROM AUTHOR]

Recently, more and more researchers have committed to designing higher-performance materials to improve the power conversion efficiencies (PCEs) of OSCs. However, the inherent laws of synthesising high-quality organic materials are still ambiguous. It is important to explore the structural effect on the photoelectric properties of the synthesised organic. In 2023, the Zou group designed two electron donors, 2DTBDT and 2DTBDT-2T, which are respectively without and with bithiophene in the molecular skeleton. The introduction of bithiophene into 2DTBDT-2T made the PCE of 2DTBDT-2T:Y6 heterojunction triple the 2DTBDT counterpart. Based on this, we selected eco-friendly electron acceptors, CBM, FBR, O-IDFBR and O-IDTBR, to compose the heterojunction with 2DTBDT and 2DTBDT-2T. The ionisation energies (IEs) and absorption spectra of all independent molecules and the excitation energy transfer (EET) couplings of heterojunction are accurately investigated from many-body Green's function theory (MBGFT). We found that the electronic structure and excitation are sensitive to the resonance-antiresonance transitions and the electron–hole interactions. The thienyl group makes the molecule lower CT energy and the stronger EET coupling of heterojunctions, to promote the efficiency of relevant OSCs. The Dexter and overlap types couplings are very important to the study on the EET of organic heterojunctions. [ABSTRACT FROM AUTHOR]

The current density–voltage characteristic (J–V) is a critical tool for understanding the behavior of solar cells. This study presents an overview of the key aspects of J–V analysis and introduces a user‐friendly flowchart that facilitates the swift identification of the most probable limiting process in a solar cell, based mainly on the outcomes of light‐intensity‐dependent J–V measurements. The flowchart is developed through extensive drift‐diffusion simulations and a rigorous review of the literature, with a specific focus on perovskite and organic solar cells. Moreover, the flowchart proposes supplementary experiments that can be conducted to obtain a more precise prediction of the primary performance losses. It therefore serves as an optimal starting point to analyse performance losses of solar cells. [ABSTRACT FROM AUTHOR]

In recent years, the utilization of renewable energy sources has emerged as a prevalent trend, both globally among countries as well as within engineering applications. Solar energy has attracted significant interest from the research community, primarily for its exceptional ability to produce electric energy in an eco-friendly and sustainable way. The current work is dedicated to introducing a powerful and effective numerical framework for analyzing the fundamental mechanical behavior of multilayered solar cell structures, namely static, vibration, and buckling problems. The key formulations are developed from a five-variable generalized higher-order shear deformation model in conjunction with NURBS-based isogeometric analysis (IGA). We, in this research, examine two typical kinds of flexible solar cell structures: Organic Solar Cells (OSCs) and Perovskite Solar Cells (PSCs), belonging to the latest generation and offering various excellent advantages in terms of efficiency and production costs. For the first time, we conduct comprehensive parametric investigations to evaluate how various input parameters affect the static deflections, natural frequencies as well as critical buckling parameters of two multilayered solar cell models under different conditions. The novel findings presented in this article can be referred to as valuable reference results for future analyses of static, buckling and vibration problems. Furthermore, the insights obtained will be pivotal for guiding future analyses, designs, and fabrications of multilayered solar cell structures. [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.

The poly3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) hole transport layer (HTL) has always played a crucial role in achieving high-efficiency organic solar cells (OSCs) owing to its unique advantages of suitable energy levels and high optical transparency. However, the inherent insulation and easy aggregation property of PSS results in relatively low conductivity and high surface roughness of the PEDOT:PSS film, which is unfavorable for charge transport and the morphology of the top layer. To address these problems, we use PEDOT:PSS diluted in a series of alcoholic solvents and evaluate them on the PM6:Y6 system. Among these, the PM6:Y6 devices using PEDOT:PSS modified with ethanol as the HTL demonstrate the best vertical phase segregation and carrier extraction. In addition, the PEDOT:PSS film with added ethanol also has the smoothest surface compared to those diluted in the other alcoholic solvents. Finally, a high power conversion efficiency of 18.13% was obtained with the PM6:Y6 devices based on PEDOT:PSS modified by ethanol. This work provides a sufficient reference for the alcoholic modification of PEDOT:PSS and also proposes a feasible solution for high-efficiency OSCs. [ABSTRACT FROM AUTHOR]

Binary organic solar cells (OSCs) having a controllable phase‐separated morphology of active layers and simple solution manufacturing are desirable for organic photovoltaic adaptation. However, low hole mobility and an unbalanced hole‐ and electron transport reduce the power conversion efficiency (PCE) of the OSCs. Here, a highly efficient binary OSC with a poly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) buffer layer as a hole transport layer (HTL) via using a water‐soluble sulfonate to wrap the PEDOT:PSS core‐shell structures in solutions is reported. The PEDOT1:PSS2.80 buffer layers have good merits including i) a smooth, homogeneous, and hydrophilic surface for an intimate contact, ii) a high work function and raised surface potentials with much uniform distributions for an energy band alignment, and iii) a high optical transmittance in the broad spectral region from 400 to 1100 nm along with an improved electrical conductivity. Benefiting from a raised hole mobility and a better charge‐mobility balance, the solution‐processed binary OSCs yielded a high PCE of 18.62%. 18.62% is one of the highest values among these binary OSCs based on the PEDOT:PSS HTLs and PM6:L8‐BO active layers. The PEDOT1:PSS2.80 buffer layers are superior to the pristine PEDOT1:PSS2.60 buffer layers in terms of raising the OSC efficiency. [ABSTRACT FROM AUTHOR]

Designing new acceptors is critical for intrinsically stretchable organic solar cells (IS‐OSCs) with high efficiency and mechanical robustness. However, nearly all stretchable polymer acceptors exhibit limited efficiency and high‐performance small molecular acceptors are very brittle. In this regard, we select thienylene‐alkane‐thienylene (TAT) as the conjugate‐break linker and synthesize four dimerized acceptors by the regulation of connecting sites and halogen substitutions. It is found that the connecting sites and halogen substitutions considerably impact the overall electronic structures, aggregation behaviors, and charge transport properties. Benefiting from the optimization of the molecular structure, the dimerized acceptor exhibits rational phase separation within the blend films, which significantly facilitates exciton dissociation while effectively suppressing charge recombination processes. Consequently, FDY‐m‐TAT‐based rigid OSCs render the highest power conversion efficiency (PCE) of 18.07 % among reported acceptors containing conjugate‐break linker. Most importantly, FDY‐m‐TAT‐based IS‐OSCs achieve high PCE (14.29 %) and remarkable stretchability (crack‐onset strain [COS]=18.23 %), significantly surpassing Y6‐based counterpart (PCE=12.80 % and COS=8.50 %). To sum up, these findings demonstrate that dimerized acceptors containing conjugate‐break linkers have immense potential in developing highly efficient and mechanically robust OSCs. [ABSTRACT FROM AUTHOR]

The conjugated small‐molecule materials of organic solar cells have always played a crucial role in light‐harvesting, charge transport, morphology optimization, and the attainment of efficient devices. The advancement of novel materials and the understanding of underlying molecular design rules serve as the driving force for furthering efficient and stable photovoltaic devices. Among a variety of design principles, the symmetry‐breaking strategy, which is well developed in 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d']‐s‐indaceno[1,2‐b:5,6‐b']dithiophene (ITIC)‐series acceptors, recently demonstrates great potential in small‐molecule acceptors and donors for realizing high power conversion efficiency. In this review, in order to give a deep insight on asymmetric strategy, the small‐molecule acceptors and donors are systematically summarized with asymmetric structure to elucidate structure‐performance relationship, molecular packing behaviors, and morphology evolution. Not only the delicate balance between open circuit voltage and short‐circuit current density, but also the reductions in charge recombination and non‐radiative recombination are considered to play the key points in improving the photovoltaic performance when the asymmetric molecule is used as host or guest materials. Finally, concise challenges and outlooks are provided for the future development and application of asymmetric molecules and symmetry‐breaking strategies. [ABSTRACT FROM AUTHOR]

New renewable energy sources, like solar cells, demonstrated to have environmental difficulties, pricing efficiency and other problems. In this study, the hole–electron theory has been applied by DFT and TD-DFT modeling to simulate an organic solar cell (OSC) with the special capabilities. This designed OSC applies a π-donor-π-acceptor system. It was demonstrated that Heme molecule could be chosen as an acceptor agent in this system. The modeled system has been modified by an efficient acceptor with four C60 fullerenes. This modeled system is considerable as an important charge and electron transfer at visible wavelengths of approximately 574 nm. The investigations were conducted in the two ground and excited states. The results have given a comprehensive picture of how the discussed OSC acts. The electron-donating part of this OSC actually consists of two S-donors that are connected by pyrazino[2,1,6-de]quinolizine linker. The energies of the all LUMO orbitals from donor part, Heme molecule, C60 and Heme + C60 (acceptor part) are cascaded from top to bottom. [ABSTRACT FROM AUTHOR]

Additives are frequently employed in the active layer of organic solar cells (OSCs) to fine‐tune morphology and improve overall device performance. The use of additive in electron transporting layer (ETL) has garnered less attention. In this study, poly(2‐vinyl pyridine) (P2VP) based cost‐effective ETLs are developed for OSCs. Addition of CoCl2 to the P2VP affords ETLs with enhanced conductivity and optimized work function. OSCs employing this ETL demonstrate prolonged carrier lifetime, suppressed charge recombination, and achieve higher power conversion efficiencies (PCEc) than the commonly used ETLs such as PFNBr and Phen‐NaDPO. The cost of the P2VP‐Co is merely one‐twentieth of that associated with Phen‐NaDPO or PFNBr. Mechanism studies and density functional theory (DFT) calculations reveal that the partial metal salt coordination of P2VP leaves free pyridine rings for dipole interactions with the Ag electrode, and provides higher electrostatic potentials and larger dipole moments compared to the polymer alone, thereby increasing conductivity. The polymer and metal salt additive strategy demonstrates its effectiveness in boosting device performance, offering valuable possibility for designing novel electronic materials and expanding the applications of widely available polymers. [ABSTRACT FROM AUTHOR]

A series of small molecules, T-2FB-T-ORH, T-2FB-T-BORH, and T-2FB-T-HDRH, were synthesized to have a thiophene-flanked difluorobenzene (T-2FB-T) core and alkyl-substituted rhodanine (RH) end groups for their use as nonfullerene acceptors (NFAs) in organic solar cells (OSCs). Octyl, 2-butyloctyl (BO), and 2-hexyldecyl (HD) alkyl side chains were introduced into RHs to control the material's physical properties based on the length and size of the alkyl chains. The optical properties of the three NFAs were found to be almost the same, irrespective of the alkyl chain length, whereas the molecular crystallinity and material solubility significantly differed depending on the alkyl side chains. Owing to the sufficient solubility of T-2FB-T-HDRH, OSCs based on PTB7-Th and T-2FB-T-HDRH were fabricated. A power conversion efficiency of up to 4.49% was obtained by solvent vapor annealing (SVA). The AFM study revealed that improved charge mobility and a smooth and homogeneous film morphology without excessive aggregation could be obtained in the SVA-treated film. [ABSTRACT FROM AUTHOR]

This document summarizes the research conducted by Dr. Yang Qin and his team on the design and synthesis of Pt(II)-bisacetylide-containing molecules for use in organic solar cells (OSCs). The researchers propose a new structural design called "roller wheels" that enhances π-π interactions and potentially improves device performance. They successfully synthesize three different "roller wheel" compounds and demonstrate their potential for use in OSCs. The researchers also optimize the construction of bulk heterojunction devices using different solution concentrations, spin-casting conditions, annealing temperature, and duration. They achieve power conversion efficiencies of 5.9% and 3.9% with two of the compounds. The document provides a summary of the researchers' findings and the potential applications of their work. [Extracted from the article]

Spontaneous photo-charge (SP) generation within the non-fullerene (NFA) bulk helps avoid exciton (EX) related loss as compared to the traditional heterojunction route in organic solar cells (OSCs). Unfortunately, the promising SP utilization attracts little attention at this time due to the lack of knowledge on its specific contribution to the photovoltaic performance and rational optimization in high-efficiency devices. To fill the gap, the NFAs' SP characteristics are related with their photocurrent loss and power conversion efficiency (PCE) in state-of-the-art materials. Though higher SP population is good for efficient EX utilization, it simultaneously acts as an additional photo-charge recombination channel. The former can be further enhanced by increasing the NFAs' crystallinity with preferred lamellar growth, and the latter can be suppressed via electric doping. With the aid of the two-step optimization strategy, the total photocurrent loss is reduced from 14.4% to 4.8%, accompanying with PCE increment from 16.9% to 18.5%. The SP utilization strategy is finally applied in the semitransparent OSCs (ST-OSCs), due to its less heterojunction area sensitive photo-charge generation characteristic. A light utilization efficiency (LUE) is then increased from 3.21% to 3.77%. The findings highlight the pursue of efficient SP utilization as a new design philosophy in future OSCs' progresses. [ABSTRACT FROM AUTHOR]

Polythiophene (PTs) is a promising electron donor in organic solar cells (OSCs) due to its simple structure and excellent synthetic scalability. However, the high HOMO (highest occupied molecular orbital) energy level of PTs and the unfavorable active layer morphology limit the performance improvement of PTs-based OSC device. Herein, in order to solve the disadvantage of high HOMO energy level of PTs, a highly planar polymer donor poly(thiazole-ethylene) derivatives(PTzV-T) was designed and synthesized by introducing an ester-functional thiazole-vinyl structure as electronwithdrawing unit into the reported poly(thiophene vinylene) derivative (PTVT-T). The aggregation behavior and energy structure were characterized by ultraviolet-visible (UV-Vis) absorption spectroscopy, electrochemical cyclic voltammetry and two-dimensional grazing incidence wide-angle X-ray scattering. Results show that the polymer PTzV-T has a low HOMO energy level (−5.88 eV) and solid planarity, and shows different preaggregation behaviors and temperature dependence in chloroform, chlorobenzene and o-xylene solvents. The films prepared with these three solvents also show different crystal packing modes and crystallinity [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although fullerene derivatives such as [6,6]‐phenyl‐C61/C71‐butyric acid methyl ester (PC61BM/PC71BM) have dominated the the photoactive acceptor materials in bulk heterojunction organic solar cells (OSCs) for decades, they have several drawbacks such as weak absorption, limited structural tunability, prone to aggregation, and high costs of production. Constructing non‐fullerene small molecules with three‐dimensional (3D) molecular geometry is one of the strategies to replace fullerenes in OSCs. In this study, a 3D molecule, contorted hexa‐cata‐hexabenzocoronene tetra perylenediimide (HBC‐4‐PDI), was designed and synthesized. HBC‐4‐PDI shows a wide and strong light absorption in the whole UV‐vis region as well as suitable energy levels as an acceptor for OSCs. More importantly, the 3D construction effectively reduced the self‐aggregation of c‐HBC, leading to an appropriate scale phase separation of the blend film morphology in OSCs. A preliminary power conversion efficiency of 2.70 % with a champion open‐circuit voltage of 1.06 V was obtained in OSCs with HBC‐4‐PDI as the acceptor, which was the highest among the previously reported OSCs based on c‐HBC derivatives. The results indicated that HBC‐4‐PDI may serve as a good non‐fullerene acceptor for OSCs. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have drawn considerable attention in the last decade due to the great potential of light weight, flexibility, and low-cost solution processing. Particularly, Y-series non-fullerene acceptors (NFAs) including small molecular acceptors (SMAs) and polymerized small molecular acceptors (PSMAs) have become research hot spots due to their excellent power conversion efficiency. Side chain engineering is crucial to adjust the solubility and crystallinity of NFAs, which will significantly affect the morphology of active layers and the efficiency of OSCs. However, the understanding of side chain engineering on NFAs is still limited and lacks a systematic review. This review aims to provide a brief summary of the recent developments in side chain engineering of NFAs, with a special focus on the design and application of Y-series SMAs and PSMAs for high-efficiency non-fullerene organic solar cells (NF-OSCs). In addition, the review also points out challenges and provides useful guidance regarding side chain regulation for Y-series NFAs. [ABSTRACT FROM AUTHOR]

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.

In this paper, a novel structure of multilayer organic photovoltaic cell has been designed and simulated. The integration of Poly(3-hexylthiophene-2,5-diyl) (P3HT) buffer layer and Poly(9,9-bis(3’-(N,N-dimethyl) N- ethylammoinium propyl-2,7-fluorene)-alt-2,7-(9,9 dioctyl fluorene)) dibromide (PFN:BR) electron transport layer (ETL) in the proposed solar cell has improved the performance significantly. The various performance measuring parameters like power conversion efficiency (PCE), short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), quantum efficiency (QE) have improved significantly. Furthermore, the effect of different layer thickness, the density of traps $N_{t}$ and temperature on the proposed solar cell has been studied and the optimum value has been obtained. It has been observed that after optimizing the different parameters of the proposed structure, the performance measuring parameters shows an improvement of 14%, 33.3%, 200% and 300% in Voc FF, Jsc and PCE respectively over the reported organic solar cells. Further, a QE of about 90% is achieved in the proposed structure.

Graphene and related materials have been employed in several applications till date due to the unique set of properties. Research in the area of organic solar cells and smart windows are important to meet the increasing global energy demands and to realize the future goal of zero energy buildings. Here, we present a summary of the important research progress in application of graphene and related materials in organic solar cells and smart windows. This review starts by introducing the need of photovoltaic technology including organic solar cells and smart windows. The remaining sections are broadly divided into two sections – the first one briefly introduces organic cells and their different types, and the next section focuses on the different chromogenic technologies used in smart windows. After a brief overview of graphene, the application of graphene and related materials in organic cells and smart windows are presented. In the end, some of the major challenges and possible research directions are also outlined. Hopefully, this review will shed light on the recent trends and directions to achieve enhancement in performance of organic solar cells and smart windows with integration of graphene and provide overview for researchers about this novel field. [ABSTRACT FROM AUTHOR]

In order to identify high‐performance non‐fused ring electron acceptors for bulk heterojunction (BHJ) solar cells, six structurally diverse molecules are designed and categorized into two series. The first series is anchored by R1 as the reference molecule, featured fixed BDT, IC‐2F end groups and modified π bridges. The second series is anchored by R2 as the reference molecule, incorporated a terminal IC‐2F and a central core modified with EDOT bridge. The electronic structure and photoelectric properties of all acceptor molecules were investigated using density functional theory (DFT) and time‐dependent density functional theory (TD‐DFT). Charge transfer matrix (CTM), Density of states (DOS) and Reorganization energy (RE) etc. were analyzed to provide fundamental knowledge on charge transport and electronic excitation. Among the studied molecules, W2 exhibited a smaller energy gap (1.74 eV) compared to the other molecules, effectively transferring its electron from HOMO to LUMO. At the same time, the W2 molecule has excellent Voc and FF. Furthermore, W2 displayed the largest λmax redshift compared to R1. Although W3 had a smaller value of λh, the comprehensive photovoltaic parameters of W2 were more excellent. The research results not only demonstrated the feasibility of introducing different alkoxy groups to alter the structure of the π bridge and central core is a feasible method for constructing high‐performance NFREAs, but also highlighted that BDT cores combined with EDOT bridges are among the most promising small molecule acceptors (SMAs) that could be considered as reasonable candidates for synthesis and incorporation into organic solar cells. The results of this study are expected to provide seminal ideas for the design of high‐performance non‐fullerene acceptors. [ABSTRACT FROM AUTHOR]

Charge extraction layers play a crucial role in developing the performance of the inverted organic solar cells. Using a transparent metal oxide with appropriate work function to the photoactive layer can significantly decrease interface recombination and enhance charge transport mechanism. Therefore, electron selective films that consist of aluminium-doped titanium dioxide (TiO2:Al) with different concentrations of Al (0.4, 0.8, and 1.2)wt % were prepared using sol-gel technique. The inverted organic solar cells PCPDTBT: PCBM with Al doped TiO2 as electron extraction layer were fabricated. It is well known that Al doping concentration potentially affects the physical characteristics of the TiO2 by controlling the optical, morphological, and structural properties. The effect of Al incorporation on the optical and morphological properties of the prepared films were analysed using UV-Vis spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The current-voltage (J-V) curves of the PCPDTBT: PCBM organic solar cells show that the TiO2:Al layer with 0.8% Al wt%, has the highest power conversion efficiency which is 3.02%. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the tactful material design, skillful device engineering, and in‐depth understanding of morphology optimization, organic solar cells (OSCs) have achieved considerable success. Therefore, OSCs have reached high power conversion efficiencies (PCEs) exceeding 19%. Especially, continuously emerging new materials have been considered as one of the key factors to improve the PCEs of OSCs. Among molecular design strategies, side‐chain engineering is an easy and commonly‐used means which can optimize the solubility, alter intermolecular stacking arrangement, fine‐tune the open circuit voltage (VOC), thus ultimately improve the performance. As hybrid side chains, silane and siloxane side chains have considerable effects, not only in increasing the carrier mobility and tuning the energy level, but also in affecting the crystallinity and molecular orientation. In this review, the latest developments in photovoltaic materials based on silane and siloxane side chains are presented to illustrate the structure‐property relationships. The review comprehensively includes silane‐side based polymer/small molecule donors; siloxane‐side based polymer/small molecule donors, and polymer/small molecule acceptors. Then the similarities and differences between these two side chains are demonstrated. Finally, the possible applications and future prospects of silane and siloxane side chains are presented. [ABSTRACT FROM AUTHOR]

Herein, a time‐resolved electrical measurement is developed to observe the transient impedance of organic photovoltaics (OPV) and traced the initial photocarrier generation dynamics with the time region from 10 ns to 190 μs. A light‐triggered time‐domain reflectometry is adopted to observe the initial carrier dynamics in OPV by synchronizing rectangular light pulses from LED with a transient impedance probe pulse. Both the rising and recovery processes of OPV are observed in detail. The time evolution of the photocarrier distribution is calculated based on the diffusion–recombination scheme and is discussed in the initial process of photocarrier generation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: With the tactful material design, skillful device engineering, and in‐depth understanding of morphology optimization, organic solar cells (OSCs) have achieved considerable success. Therefore, OSCs have reached high power conversion efficiencies (PCEs) exceeding 19%. Especially, continuously emerging new materials have been considered as one of the key factors to improve the PCEs of OSCs. Among molecular design strategies, side‐chain engineering is an easy and commonly‐used means which can optimize the solubility, alter intermolecular stacking arrangement, fine‐tune the open circuit voltage (VOC), thus ultimately improve the performance. As hybrid side chains, silane and siloxane side chains have considerable effects, not only in increasing the carrier mobility and tuning the energy level, but also in affecting the crystallinity and molecular orientation. In this review, the latest developments in photovoltaic materials based on silane and siloxane side chains are presented to illustrate the structure‐property relationships. The review comprehensively includes silane‐side based polymer/small molecule donors; siloxane‐side based polymer/small molecule donors, and polymer/small molecule acceptors. Then the similarities and differences between these two side chains are demonstrated. Finally, the possible applications and future prospects of silane and siloxane side chains are presented. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have attracted extensive attention from both academia and industry in recent years due to their remarkable improvement in power conversion efficiency (PCE). However, the Golden Triangle (the balance of efficiency‐stability‐cost) required for large‐scale industrialization of OSCs still remains a great challenge. Here, a new nonfused‐ring electron acceptor (NFREA) BF and its polymerized counterpart PBF were designed and synthesized, and their photovoltaic performance, storage stability and material cost were systematically investigated. When blended with a widely‐used polymer donor PBDB‐T, the PBF‐based all‐polymer solar cell (all‐PSC) displayed a record high PCE of 12.61% for polymerized NFREAs (PNFREAs) with an excellent stability (95.2% of initial PCE after 800 h storage), superior to the BF counterpart. Impressively, PBF‐based all‐PSC possesses the highest industrial figure‐of‐merit (i‐FOM) value of 0.309 based on an efficiency‐stability‐cost evaluation, in comparison to several representative OSC systems (such as PM6:Y6 and PBDB‐T:PZ1). This work provides an insight into the balance of efficiency, stability, and cost, and also indicates that the PNFREAs are promising materials toward the commercial application of OSCs. [ABSTRACT FROM AUTHOR]

In organic solar cells, the singlet and triplet excitons dissociate into free charge carriers with different mechanisms due to their opposite spin state. Therefore, the ratio of the singlet and triplet excitons directly affects the photocurrent. Many methods were used to optimize the performance of the low-efficiency solar cell by improving the ratio of triplet excitons, which shows a long diffusion length. Here we observed that in high-efficiency systems, the proportion of singlet excitons under linearly polarized light excitation is higher than that of circularly polarized light. Since the singlet charge transfer state has lower binding energy than the triplet state, it makes a significant contribution to the charge carrier generation and enhancement of the photocurrent. Further, the positive magnetic field effect reflects that singlet excitons dissociation plays a major role in the photocurrent, which is opposite to the case of low-efficiency devices where triplet excitons dominate the photocurrent.