Efficient Organic Photovoltaics Research Articles

Optimization of Polymers for Organic Solar Cells: Effects of Alkyl, Fluorinated and Thiophenated Chains.

This paper explores optimization strategies for polymeric materials in organic solar cells (OSCs) with the focus on varying alkyl side chain, addition of fluorine atom, and thiophenated derivatives onto polymer. As such, it outlines the significance of renewable energy sources and the potential of photovoltaic technologies, particularly organic photovoltaics (OPVs). Objectives include factors affecting power conversion efficiency (PCE), open-circuit voltage (Voc), aggregation tendencies, and optoelectronic properties in OPVs. The scope encompasses the impact of alkyl as well as the comparison between fluorinated and chlorinated polymers and the role of thiophene units to obtain an efficient organic solar cell. The review examines how alkyl chain structures influence thin film morphology, packing, and device performance, comparing linear and branched configurations. It also explores the role of halogenated polymers in modifying electronic properties and stability, focusing on the comparative performance between fluorinated and chlorinated polymers. The importance of thiophene units in polymer design for OPVs is discussed, along with performance comparisons based on different architectures. The paper summarizes key findings regarding the impact of various side chain modifications for OPVs device performance and outlines future research directions to enhance efficiency, stability, and scalability. It suggests exploring novel material design to further optimize OSCs.

Coplanar Dimeric Acceptors with Bathochromic Absorption and Torsion-Free Backbones through Precise Fluorination Enabling Efficient Organic Photovoltaics with 18.63% Efficiency.

Giant dimeric acceptors (GDAs), a sub-type of acceptor materials for organic solar cells (OSCs), have garnered much attention due to the synergistic advantages of their monomeric and polymeric acceptors, forming a well-defined molecular structure with a giant molecular weight for high efficiency and stability. In this study, for the first time, two new GDAs, DYF-V and DY2F-V are designed and synthesized for OSC operation, by connecting one vinylene linker with the mono-/di-fluorinated end group on two Y-series monomers, respectively. After fluorination, both DYF-V and DY2F-V exhibit bathochromic absorption and denser packing modes due to the stronger intramolecular charge transfer effect and torsion-free backbones. Through precise fluorination, the DYF-V-based devices exhibit the highest performance of 18.63% among the GDA-based OSCs, outperforming its non-fluorinated counterpart, DY-V-based ones (16.53%). Theoretical and morphological results demonstrate that proper fluorination in DYF-V-based devices strengthens intra/intermolecular interactions for enhanced crystallinity, superior phase segregation, and less energy disorder, which is beneficial for fast exciton dissociation, rapid carrier transport, and suppressed charge recombination. The work demonstrates that proper fluorination on GDAs with rigid coplanar backbones is effective for broader photon harvesting, stronger packing, and robust stability in GDA-based OSCs.

Donor-Interacting Arylated Carbazole Self-Assembled Monolayer Enables Highly Efficient and Stable Organic Photovoltaics.

Carbazole-derived self-assembled monolayers (SAMs) are promising materials for hole-extraction layer (HEL) in conventional organic photovoltaics (OPVs). Here, a SAM Cbz-2Ph derived from 3,6-diphenylcarbazole is demonstrated. The large molecular dipole moment of Cbz-2Ph allows the modulation of electrode work function to facilitate hole extraction and maximize photovoltage, thus improving the OPV performance. Additionally, the flanking aryls of Cbz-2Ph help establish CH-π interactions for forming a dense and well-organized SAM HEL and exhibit stronger van der Waals interactions with the donor PM6 than acceptor BTP-eC9. The stronger SAM-donor interactions modulate the PM6 distribution in PM6:BTP-eC9 bulk-heterojunction film, leading to PM6 enrichment near HEL to facilitate efficient hole extraction to the ITO anode in conventional p-i-n OPVs. Consequently, binary PM6:BTP-eC9-based devices incorporating the Cbz-2Ph HEL demonstrate an impressive efficiency of 19.18%. These cells also showcase excellent operational stability, with a T80 lifetime of ≈1260 h at the maximum power point, over 10 times longer than those using the traditional PEDOT:PSS HEL (T80 ≈96h). Furthermore, the universal applicability of Cbz-2Ph as a HEL is evident through its successful implementation in PM6:BTP-eC9:L8-BO-F-based ternary devices and PM6:BTP-eC9-based printed OPV devices, achieving a PCE of 19.30% and 16.96%, respectively.

Resolving the molecular diffusion model based on butterfly-shaped non-fused ring electron acceptors for efficient ternary organic photovoltaics with improved stability

By developing butterfly-shaped non-fused ring electron acceptors, X7-D and X8-D, the molecular diffusion model was resolved, guiding organic photovoltaics toward higher efficiency and better stability.

Hole-Transport-Layer-Free Organic Solar Cells with Enhanced Efficiency Upon Halogenated Solvent Treatment.

Typical PEDOT:PSS hole-transporting layers frequently present some issues, including mismatched energy levels, high acidity, severe hygroscopicity, etc., all of which significantly weaken device performance. Herein, an approach of halogenated solvent treatment to modulate the physical properties of indium tin oxide (ITO) substrates is employed. Four halogenated-ITO anodes (named ITO-F, ITO-Cl, ITO-Br and ITO-I) are achieved by ITO substrates immersed in hydrogen peroxide co-solvents mixed with 1,2-difluorobenzene, 1,2-dichlorobenzene, 1,2-dibromobenzene and 1,2-diiodobenzene, respectively, and upon UV illumination. The work functions of the ITO-F/Cl/Br/I anodes increase from 4.63eV for ITO to 5.30, 5.32, 5.24, and 5.28eV, respectively, which are close to 5.22eV for ITO/PEDOT:PSS. Additionally, the investigated PM6:L8-BO:BTP-eC9 devices based on various anodes showed power conversion efficiencies (PCEs) of 17.81% for ITO-F, 19.48% for ITO-Cl, 17.05% for ITO-Br, 17.34% for ITO-I and 18.70% for ITO/PEDOT:PSS, respectively. In particular, a comprehensive experimental analysis is conducted to establish connections between theoretical calculations, blend morphology and physical dynamics, and further elucidate the factors that cause differences in device efficiencies. This work manifests the advantages of the proposed halogenated ITO for realizing highly efficient organic photovoltaics.

Investigating Dopant Effects in ZnO as an Electron Transport Layer for Enhanced Efficiency in Organic Photovoltaics

AbstractThe power conversion efficiencies of organic solar cells greatly depend on the device architecture and choice of charge transporting materials. Improved power conversion efficiency (PCE) for inverted organic solar cells is observed when using Sn‐doped ZnO as the electron transporting layer. By doping the elements with different numbers of valence electrons (Al3+ and Sn4+ ions) into the ZnO matrix, device conversion efficiencies of 8.69% and 9.21%, respectively, are achieved. Conductive atomic force microscopy (CAFM) observations reveal that the Sn‐doped ZnO film exhibits better conductivity due to its larger number of carrier charges. X‐ray photoemission spectroscopy (XPS) indicates larger oxygen vacancies (OV) in Sn‐doped ZnO. Electrochemical characterization exhibits that there is a reduction in series resistance and charge transfer (CT) resistance for SZO, indicating the optimal charge transport capability of the electron transport layer (ETL). Ultrafast time‐resolved studies further show that, in comparison with Al‐doped ZnO and un‐doped ZnO, the elevated carrier concentration in Sn‐doped ZnO plays a significant role in augmenting the photocurrent. Thus, it is determined how dopants in ETL influence CT mechanisms, enhancing the photovoltaic conversion efficiency, thus contributing to the development of cost‐effective and efficient photovoltaic technologies.

Tailoring Optoelectronic Properties of A-D–A Type Nonfullerene Acceptors with Fused Aromatic Thiophene-Furan Bridges for Efficient Organic Photovoltaics

We report the molecular engineering of new small molecule-based medium band gap nonfullerene acceptors containing a strong electron acceptor backbone of DPP attached to the [Formula: see text]-spacer-based furan linker. We systematically designed five new designed molecules (H1−H5) and studied their structural, optical, photovoltaic and optoelectronic characteristics. We employed advanced quantum chemical approaches to characterize these molecules (H1–H5) and synthetic reference molecule R. The designed molecules exhibit improved light absorption and narrower energy bandgaps in contrast to R. Moreover, a lower excitation energy of these molecules (H1−H5) enables easier excitation and phase separation in the excited states. Analysis of the geometric and physiochemical properties provides evidence of the enhanced photovoltaic and optoelectronic characteristics of these molecules in comparison to the R molecule and other molecules with similar structures that have been previously reported. Among all these designed series, H3 stands out with a minimal 1.99 eV band gap, excellent hole ([Formula: see text] 0.0079 eV) and electron ([Formula: see text] 0.0076 eV) mobility, low binding energy ([Formula: see text] 0.42 eV) and highly red-shifted absorption characteristics. Furthermore, these molecules also displayed good electron and hole mobilities, indicating their tremendous potential in producing high-efficiency organic solar cells. Therefore, this study showcases the molecular modeling and effectiveness of these DPP and furan-containing molecules and their promising potential for organic photovoltaics.

19.5% Inverted organic photovoltaic with record long-lifetime via multifunctional interface engineering featuring radical scavenger

Advances in improving the operational lifetime of highly efficient organic photovoltaic (OPV) and understanding photo-degradation mechanisms in molecular level are currently limited, especially on the promising inverted OPV, posing critical challenges to commercialization. Here, we demonstrate a radical scavenger (3-(3,5-Di-tert-butyl-4-hydroxyphenyl)propionic acid) capped ZnO (BHT@ZnO) nanoparticles as the electron transport layer providing effective surface oxygen vacancy passivation and reactive radical capture capability. Encouragingly, this BHT@ZnO-based empowered device achieves a record inverted OPV efficiency of 19.47% (Certificated efficiency: 18.97%). The devices demonstrate light soaking-free behavior, long-term stability under ISOS-D-1 (94.2% PCE retention after 8904 h in ambient) and ISOS-L-1 testing protocol (81.5% PCE retention after 7724 h in MPP). More importantly, we elucidate detailed degradation mechanism in OPV involving selectively catalytic degradation of donor and acceptor by superoxide and hydroxyl radicals, respectively, as well as the degradation pathway of polymer donor upon radiation exposure. Performance enhancement and mechanism comprehension provide strong support for the development of OPV technology.

Upper Layer-Modulated Pseudo Planar Heterojunction with Metal Complex Acceptor for Efficient and Stable Organic Photovoltaics.

Modulating self-aggregation and charge transport in the upper acceptor layer of the pseudo planar heterojunction (PPHJ) is crucial for enhancing dielectric constant and suppressing trap density, leading to efficient and stable organic photovoltaics (OPVs). In this work, a metal complex acceptor (MCA), PtAC-Cl, is selectively incorporated into the upper host Y6 layer of PPHJ to regulate morphology and fill trap states. There exists a strong chemical interaction between PtAC-Cl and Y6, which can promote electron transfer. PtAC-Cl can regulate the self-aggregation and extend the exciton diffusion length of Y6, resulting in enhanced charge transport and reduced energetic disorder. Consequently, upper layer-modulated PPHJ devices with PtAC-Cl achieved a significant power conversion efficiency of 18.16%. The universality of PtAC-Cl is also demonstrated in PM6/eC9 and PM6/L8-BO systems, achieving the highest PCEs of 18.79 and 19.30%, respectively. All the improved PCEs are mainly attributed to the enhanced fill factor (FF) and short circuit current (Jsc) compared with the controls. Additionally, PtAC-Cl significantly improves the thermal stability and photostability of the devices, with a T80 lifetime of ≈ 401 h under continuous illumination with simulated 1-Sun light and 1265 h under continuous heating at 70°C. Overall, this work introduces the concept of MCA and proposes a practical and efficient method to enhance the efficiency and stability of OPVs through selective upper-layer modulation in PPHJ with MCA.

Balanced Miscibility and Crystallinity by 2D Acceptors Enabled Halogen-Free Solvent-Processed Organic Solar Cells to Achieve 19.28% Efficiency.

Two highly crystalline 2D acceptors, ATIC-C11 and ATIC-BO, with acenaphthene-expanded quinoxaline central cores, have been demonstrated with very different characteristics in ternary organic solar cells (OSCs). The difference in side chains induces their distinctive molecular packing mode and unique crystal structure, in which ATIC-C11 displays a 3D structure with an elliptical framework, and ATIC-BO gives a rectangular framework. Their high crystallinity contributes to organized molecular packing in ternary devices, thus low energetic disorder and suppressed energy loss. Through the analysis of morphology and carrier kinetics, it is found that ATIC-BO's strong self-aggregation and immiscibility induce large aggregates and severely impede charge transfer (CT) and dissociation. Conversely, ATIC-C11's suitable crystallinity and compatibility positively regulate the crystalline kinetics during film formation, thus forming much-ordered molecular packing and favorable phase separation size in blend films. As a result, ATIC-C11-based ternary devices achieve a high efficiency of 19.28% with potential in scalability and stability, which is the top-ranking efficiency among nonhalogenated solvent-processed OSCs. This work not only displays highly efficient and stable halogen-free solvent-processed organic photovoltaics (OPVs), but also offers a new thought for material design and selection rule on the third component in highly efficient ternary OSCs.

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7 .

Given homomorphic fluorine (F), chlorine (Cl) and bromine (Br) atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and locations on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH-F, CH-C and CH-B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re-permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH-B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH-B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH-B affords the first class binary OSC efficiency of 19.78 %, moreover, the highest efficiency of 18.35 % thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record-breaking OSCs.

Rebuilding Peripheral F, Cl, Br Footprints on Acceptors Enables Binary Organic Photovoltaic Efficiency Exceeding 19.7 %

AbstractGiven homomorphic fluorine (F), chlorine (Cl) and bromine (Br) atoms are featured with gradually enlarged polarizability/atomic radius but decreased electronegativity, the rational screen of halogen species and locations on small molecular acceptors (SMAs) is quite essential for acquiring desirable molecular packing to boost efficiency of organic solar cells (OSCs). Herein, three isomeric SMAs (CH−F, CH−C and CH−B) are constructed by delicately rebuilding peripheral F, Cl, Br footprints on both central and end units. Such a re‐permutation of peripheral halogens could not only maintain the structural symmetry of SMAs to the maximum, but also acquire extra asymmetric benefits of enhanced dipole moment and intramolecular charge transfer, etc. Moreover, central brominating enhances molecular crystallinity of CH−B without introducing undesirable steric hindrance on end groups, thus rendering a better balance between high crystallization and domain size control in PM6:CH−B blend. Further benefitting from the large dielectric constant, small exciton binding energy, optimized molecular packing and great electron transfer integral, CH−B affords the first class binary OSC efficiency of 19.78 %, moreover, the highest efficiency of 18.35 % thus far when increasing active layer thickness to ~300 nm. Our successful screening in rebuilding peripheral halogen footprints provides the valuable insight into further rational design of SMAs for record‐breaking OSCs.

Fine-Tuning Conformation of PEDOT Chains Enables Simultaneously Enhanced Conductivity, Work Function, Transmittance, and Waterproofness in PEDOT:PSS Interlayer for Highly Efficient and Stable Organic Photovoltaics.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely utilized as the hole transport layer (HTL) inorganic photovoltaics (OPVs) because of its low-temperature solution processing peculiarity, high optical transmittance, and excellent mechanical flexibility. However, the core-shell structure of PSS coated PEDOT results in relatively low conductivity, work function, transmittance and waterproofness of PEDOT:PSS interlayer, limiting the photovoltaic performance and stability of OPVs. Here, the conformation of PEDOT chains are regulated from helical benzoyl to linear quinone structure via incorporation of 2D Cd0.85PS3Li0.15H0.15dopant into the conventional PEDOT:PSS interlayer, promoting an interpenetrating network structure in PEDOT:PSS interlayer and forming an efficient hole transport channel from active layer to ITO electrode. Such features significantly improve the electrical conductivity, work function, and transmittance of PEDOT:PSS interlayer. In consequence, the maximum power conversion efficiency (PCE) of D18:L8-BO, PBDB-T:ITIC, as well as PTzBI-dF:L8-BO based OPVs ameliorated from 18.37%, 8.94%, and 15.80% to 19.26%, 10.00%, and 16.83%, respectively. The application of Cd0.85PS3Li0.15H0.15 doping PEDOT:PSS strategy demonstrates great potential for the development of strongly conductive, large-work-function, highly transparent, and excellent-waterproof PEDOT:PSS interlayer toward highly efficient and stable OPVs.

A butterfly-shaped acceptor with rigid skeleton and unique assembly enables both efficient organic photovoltaics and high-speed organic photodetectors.

It remains challenging to design efficient bifunctional semiconductor materials in organic photovoltaic and photodetector devices. Here, we report a butterfly-shaped molecule, named WD-6, which exhibits low energy disorder and small reorganization energy due to its enhanced molecular rigidity and unique assembly with strong intermolecular interaction. The binary photovoltaic device based on PM6:WD-6 achieved an efficiency of 18.41%. Notably, an efficiency of 19.42% was achieved for the ternary device based on PM6:BTP-eC9:WD-6. Moreover, the photodetection device based on WD-6 demonstrated an ultrafast response speed (205ns response time at λ of 820nm) and a high cutoff frequency of -3dB (2.45MHz), surpassing the values of most commercial Si photodiodes. Based on these findings, we showcased an application of the WD-6-based photodetection device in high-speed optical communication. These results offer valuable insights into the design of organic semiconductor materials capable of simultaneously exhibiting high photovoltaic and photodetective performance.

Optimizing Exciton Diffusion and Carrier Transport for Enhanced Efficiency in Q‐PHJ and BHJ Organic Solar Cells

AbstractExciton diffusion and carrier transport are two critical factors that determine the efficiency of organic photovoltaics (OPVs). However, the relationship between these two factors has not been extensively studied. Designing non‐fullerene acceptors (NFAs) with efficient diffusion coefficients and high electronic transmittance is a key area of focus. In this study, materials for bulk‐heterojunction (BHJ) and quasiplanar‐heterojunction (Q‐PHJ) devices are synthesized to validate the desired differences in crystallinity. The single crystal of BOBO4Cl‐βδ demonstrated the most compact packing structure, with an improved planar configuration and closer π···π distances, resulting in higher electron mobility and superior exciton diffusion coefficient. Consequently, BOBO4Cl‐βδ‐based devices achieved a power conversion efficiency (PCE) of 17.38% in Q‐PHJ, compared to a lower PCE of 14.75% in BHJ devices. Furthermore, incorporating BOBO4Cl‐βδ into the D18/L8‐BO Q‐PHJ system increased the PCE from 17.98% to 18.81%, one of the highest values recorded for Q‐PHJ devices. This improvement is attributed to strong crystallinity of BOBO4Cl‐βδ, which enhances the packing arrangement and improves the exciton diffusion coefficient. Our work highlights the importance of molecular design with tunable exciton diffusion and carrier transport for BHJ and Q‐PHJ OPV architectures and reveals the relationship between them, which contributes to the achievement of high‐performance NFAs.

Tailoring Light-Harvesting in Zn-Porphyrin and Carbon Fullerene based Donor-Acceptor Complex through Ethynyl-Extended Donor π-Conjugation.

Organic photovoltaic efficiency though currently limited for practical applications, can be improved by means of various molecular-level modifications. Herein the role of extended donor -conjugation through ethynyl-bridged meso-phenyl/pyridyl on the photoinduced charge-transfer kinetics is studied in noncovalently bound Zn-Porphyrin and carbon-fullerene based donor-acceptor complex using time-dependent optimally tuned range-separated hybrid combined with the kinetic rate theory in polar solvent. Noncovalent dispersive interaction is identified to primarily govern the complex stability. Ethynyl-extended -conjugation results in red-shifted donor-localized Q-band with substantially increased dipole oscillator strength and smaller exciton binding energy, suggesting greater light-harvesting efficiency. However, the low-lying charge-transfer state below to the Q-band is relatively less affected by the ethynyl-extended -conjugation, yielding reduced driving forces for the charge-transfer. Detailed kinetics analysis reveals similar order of charge-transfer rate constants (~1012 s-1) for all donor-acceptor composites studied. Importantly, enhanced light-absorption, smaller exciton binding energy and similar charge-transfer rates together with reduced charge-recombination make these complexes suitable for efficient photoinduced charge-separation. These findings will be helpful to molecularly design the advanced organic donor-acceptor blends for energy efficient photovoltaic applications.

Improving Efficiency of Organic Photovoltaics by Manipulating Critical Concentration of Polymer in Bulk‐Heterojunction Solution

AbstractIn the advancement of organic photovoltaics (OPV) toward scale‐up production, how to mitigate the batch instability of electron‐donating polymers originated from varied molecular weights remains a great challenge. By taking into consideration the relationship between the molecular weight of electron‐donating polymers and the relevant critical concentration (c*) of the solution, herein it is demonstrated that the aggregation behavior of the electron‐donating polymers can be tailored through manipulating c* of the polymer solution. It is interesting to note that the excessive aggregation in low‐molecular‐weight fractions can be circumvented while the favorable mixing ratio can be identified. By preparing the binary bulk heterojunction film under c*‐defined conditions for mixed‐molecular‐weight polymers, a notable power conversion efficiency of 19.1% for binary devices is achieved. Of particular importance is that a linear interrelation can be established between the c* for the maximum PCE and c* for the low‐molecular‐weight fraction aggregation, validating those straightforward spectra measurements can accurately and rationally guide the molecular weight mixing of photovoltaic donor polymers, thereby fully harnessing the potent driving force and affinity inherent to the low‐molecular‐weight fractions. These findings offer a straightforward and logical framework for addressing batch variability in the large‐scale production of high‐performance OPV devices.

Air processed, high open‐circuit voltage indoor organic photovoltaic cells based on side chain modified N‐annulated perylene diimides

AbstractTo achieve high‐performance indoor organic photovoltaics (OPVs), it is important to match the photoactive layer optical absorption with the light‐source emission. This can be accomplished by developing organic photoactive materials that can efficiently absorb visible light and thus minimize energy losses. While indoor OPVs have achieved efficiencies above 33% under low light intensities, the power output is limited by low open circuit voltages (VOC), often well below 1 V. In this study, we present a series of visible‐light absorbing (energy gap >1.90 eV) non‐fullerene acceptors (NFAs) based on perylene diimide dimers, which have been systematically modified with side chains of varying polarity and steric bulk (trimethyl benzyl, ethyl adamantane, trialkoxyl phenyl, and oligo ethylene glycol). Our results show that the incorporation of sterically bulky side chains such as ethyl adamantane and trimethyl benzyl, blended with the common widegap polymer PTQ10, provides photoactive layers with absorption greater than 2.0 eV, and consequently, VOCs higher than 1.2 V are achieved under AM 1.5 G illumination. Importantly, we found that the NFA with ethyl adamantane based side chains (tPDI2N‐ethyl adamantane, compound 4) exhibited the best performance, with minimized energy loss. As a result, devices using PTQ10:tPDI2N‐ethyl adamantane photoactive layers demonstrated excellent indoor efficiencies of over 16% and 18 μW cm−2 power output under a 2700 K LED lamp at 300 lux, and showed better repeatability compared to other systems. The PTQ10:tPDI2N‐ethyl adamantane based devices maintained a high VOC (>1.0 V) across a wide range of indoor lighting conditions, including 2700 K and 6500 K LED lamps. Overall, this work provides a sidechain engineering method to create NFAs for efficient indoor OPV devices.

Spray-Coated Transition Metal Dichalcogenides as Hole Transport Layers in Inverted NFA-Based Organic Photovoltaics with Enhanced Stability under Solar and Artificial Light

In this study, we explored the potential of exfoliated transition metal dichalcogenides (TMDs) as innovative spray-coated hole transport layers (HTLs) in organic photovoltaics (OPVs), addressing the need for efficient and stable materials in solar cell technology. This research was motivated by the need for alternative HTLs that can offer enhanced performance under varying lighting conditions, particularly in indoor environments. Employing UV-visible absorption and Raman spectroscopy, we characterized the optical properties of MoS2, MoSe2, WS2, and WSe2, confirming their distinct excitonic transitions and direct bandgap features. The nanocrystalline nature of these TMDs, revealed through XRD patterns and crystallite size estimation using the Scherrer method, significantly contributes to their enhanced physical properties and operational efficiency as HTLs in OPVs. These TMDs were then integrated into OPV devices and evaluated under standard solar and indoor lighting conditions, to assess their effectiveness as HTLs. The results demonstrated that MoS2, in particular, displayed remarkable performance, rivalling traditional HTL materials like MoO3. It maintained high power conversion efficiency across a spectrum of light intensities, illustrating its versatility for both outdoor and indoor applications. Additionally, MoS2 showed superior stability over extended periods, suggesting its potential for long-term usage in OPVs. This study contributes significantly to the field of photovoltaic materials, presenting TMDs, especially MoS2, as promising candidates for efficient and stable OPVs in diverse lighting conditions, thereby broadening the scope of solar cell applications.

Non‐fullerene acceptors with heteroatom substitution on the core moiety for efficient organic photovoltaics

Non‐fullerene acceptors with heteroatom substitution on the core moiety for efficient organic photovoltaics