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A bromine and chlorine concurrently functionalized end group for benzo[1,2-b:4,5-b']diselenophene-based nonfluorinated acceptors: new hybrid strategy to balance the crystallinity and miscibility of blend films enabling highly efficient polymer solar cells
摘要： A bromine and chlorine concurrently functionalized end group for nonfluorinated benzo[1,2-b:4,5-b']diselenophene-based acceptors: new hybrid strategy to balance the crystallinity and miscibility of blend films enabling highly efficient polymer solar cells. Dihalogenated 1,1-dicyanomethylene-3-indanone (IC) plays a key role in top-performing fused-ring electron acceptors (FREAs)-based polymer solar cells (PSCs). Here, we firstly synthesized a hybrid dihalogenated IC (IC-BrCl), which simultaneously grafted one Br atom and one Cl atom onto the same IC skeleton. Three nonfluorinated FREAs (BDSe-4Cl, BDSe-2(BrCl) and BDSe-4Br) are synthesized by employing benzo[1,2-b:4,5-b′]diselenophene-based core unit and dichlorinated IC, hybrid dihalogenated IC (IC-BrCl), and dibrominated IC for highly efficient PSCs, respectively. These three acceptors exhibit very similar absorption spectra with 1.39 eV of optical band gap, but slightly different in the HOMO/LUMO energy levels in thin films. The crystallinity of acceptors was progressively enhanced and miscibility with PM7 was gradually reduced with the increase of Br atoms. The BDSe-2(BrCl):PM7 blend films exhibited the strongest face-on crystallization orientation, the most proper phase separation feature, the highest and most balanced carrier mobility and the weakest charge recombination owing to the excellent balance of miscibility and crystallinity of blend film. Notably, BDSe-2(BrCl):PM7-based PSCs demonstrated an outstanding PCE of 14.5% with an impressive FF of 76.5%, which substantially outperformed its counterparts (13.8% for BDSe-4Cl, 13.2% for BDSe-4Br, respectively) and is the highest value in hybrid IC-based FREAs for binary PSCs. Our results demonstrated that hybrid dihalogenated IC with one Br atom and one Cl atom provide a promising strategy to tune crystallinity and miscibility of FREAs for boosting the FF and PCE of PSCs.
关键词： crystallinity,nonfluorinated acceptors,polymer solar cells,miscibility,hybrid dihalogenated IC
更新于2025-09-16 10:30:52
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Enhanced carrier mobility and power conversion efficiency of organic solar cells by adding 2D Bi<sub>2</sub>OS<sub>2</sub>
摘要： Although polymer solar cells (PSCs) have many advantages, they have obtained great progress in the two decades, the low charge carrier mobility still restricts performance progress of PSCs. Two-dimensional (2D) Bi-based semiconductor nanomaterial (Bi2OS2) can be a potential material for improving the charge carrier mobility in the active layer of PSCs, because it exhibits a high carrier mobility, suitable band gap, wide absorption range, and good stability. In this work, we synthesize the 2D Bi2OS2 nanomaterial and incorporate it into active layer of PSCs as a third component for the first time. By introduction 1 wt% 2D Bi2OS2 nanomaterial into the PSCs, the power conversion efficiency (PCE) of PSCs can be obviously improved by more than 17% comparison with binary PSCs (from 10.51% to 12.31%). The enhancement of PCE is mainly due to the improving of charge transport, surface morphology, and crystallization of active layer. It is worth noting that the 2D Bi2OS2 play the role of the heterogeneous nucleation in the active layer, resulting in the enhanced crystallization of PBDB-T and ITIC. These results not only provide a way to improve the performance of PSCs, but also show that the 2D Bi2OS2 nanomaterial has great potential application in the PSCs.
关键词： crystallinity,2D Bi2OS2 nanomaterial,Polymer solar cells,charge carrier transport
更新于2025-09-16 10:30:52
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Importance of interfacial crystallinity to reduce open-circuit voltage loss in organic solar cells
摘要： Reducing the energy loss in output voltage is critically important for further enhancing the ef?ciency of organic solar cells (OSCs). Here, we report that OSCs with high mobility and highly crystalline donor (D) and acceptor (A) materials were able to reduce an open-circuit voltage (VOC) loss. The crystallinity of the acceptor layer could be altered by appropriate selection of the three molecules with different alkyl side chain lengths. The VOC was found to increase as the crystallinity of the acceptor layer increased. The origin of the high VOC was that the highly crystalline D/A interface reduced the energy loss in the output voltage by realizing ideal band-to-band recombination. Especially, the high crystallinity of the several molecular layers (less than 6 nm) in the vicinity of the D/A interface was important for realizing the high VOC. Our results demonstrate that the careful design of the D/A interface enables high power conversion ef?ciencies to be achieved in OSCs by reducing open-circuit voltage loss.
关键词： power conversion efficiency,interfacial crystallinity,open-circuit voltage loss,organic solar cells,donor/acceptor interface
更新于2025-09-16 10:30:52
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Transmission Electron Microscopy-Based Statistical Analysis of Commercially Available Graphene Oxide Quantum Dots
摘要： Thanks to their excellent thermal and optical properties, graphene oxide quantum dots (GOQD) have been extensively explored for several applications, such as composite material, optoelectronic devices, solar cells, and ?uorescence materials, among others. Consequently, GOQDs are commercially available suspended in a solution. However, the density, size, and crystallinity of commercially available GOQDs can di?er a lot from one manufacturer to another, which rarely provide exhaustive information about them. Furthermore, a recent report has questioned the quality of graphene-based materials produced by liquid phase exfoliation. Here a statistical analysis of the quality of commercially available GOQDs, using transmission electron microscope (TEM), is presented. This technique enables to observe the internal structure, thickness, lattice structure, orientation, and local defects of the samples at atomic scale. High resolution TEM images reveal that the thickness of the GOQDs is not homogenous from center to edges within one single domain. The edges show hexagonal lattice (monolayer) while the central location shows to be rhomboidal structure (multilayer). This work provides clear statistical information about the quality of the commercially available GOQDs.
关键词： quantum dots,transmission electron microscopy,crystallinity,graphene oxide,graphene
更新于2025-09-16 10:30:52
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13.34% Efficiency Nonfullerene All-Small-Molecule Organic Solar Cells Enabled by Modulating Crystallinity of Donors via a Fluorination Strategy
摘要： Nonfullerene all-small-molecule organic solar cells (NFSM-OSCs) have shown a promising potential towards the commercialization of OSCs, owing to their unique advantages of high purity, easy synthesis and good reproducibility. However, great challenges in the modulation of phase separation morphology have limited their future development. Herein, two novel small molecular donors of BTEC-1F and BTEC-2F, derived from the small molecule DCAO3TBDTT, were designed and synthesized. While using Y6 as the acceptor, the devices based on non-fluorinated DCAO3TBDTT showed an open circuit voltage (Voc) of 0.804 V and a power conversion efficiency (PCE) of 10.64%. Mono-fluorinated BTEC-1F showed an increased Voc of 0.870 V and a PCE of 11.33%. More impressively, the fill factor (FF) of di-fluorinated BTEC-2F based NFSM-OSC was largely improved to 72.35% resulting in an impressive PCE of 13.34%, which was much higher than that of BTEC-1F (61.35%) and DCAO3TBDTT (60.95%). To the best of our knowledge, this is the highest reported PCE to date for NFSM-OSCs. BTEC-2F depicted a more compact molecular stacking and a lower crystallinity as revealed from characterization studies, which was beneficial for enhancing phase separation and carrier transport. Those results demonstrated an effective strategy to improve the performance of NFSM-OSCs via fluorination of small molecular donors and modulation of crystallinity deviation between donors and acceptors.
关键词： morphology,all-small-molecule organic solar cells,crystallinity,fluorination,orientation modulation
更新于2025-09-12 10:27:22
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13.34% Efficiency Nonfullerene All‐Small‐Molecule Organic Solar Cells Enabled by Modulating Crystallinity of Donors via a Fluorination Strategy
摘要： Nonfullerene all-small-molecule organic solar cells (NFSM-OSCs) have shown a promising potential towards the commercialization of OSCs, owing to their unique advantages of high purity, easy synthesis and good reproducibility. However, great challenges in the modulation of phase separation morphology have limited their future development. Herein, two novel small molecular donors of BTEC-1F and BTEC-2F, derived from the small molecule DCAO3TBDTT, were designed and synthesized. While using Y6 as the acceptor, the devices based on non-fluorinated DCAO3TBDTT showed an open circuit voltage (Voc) of 0.804 V and a power conversion efficiency (PCE) of 10.64%. Mono-fluorinated BTEC-1F showed an increased Voc of 0.870 V and a PCE of 11.33%. More impressively, the fill factor (FF) of di-fluorinated BTEC-2F based NFSM-OSC was largely improved to 72.35% resulting in an impressive PCE of 13.34%, which was much higher than that of BTEC-1F (61.35%) and DCAO3TBDTT (60.95%). To the best of our knowledge, this is the highest reported PCE to date for NFSM-OSCs. BTEC-2F depicted a more compact molecular stacking and a lower crystallinity as revealed from characterization studies, which was beneficial for enhancing phase separation and carrier transport. Those results demonstrated an effective strategy to improve the performance of NFSM-OSCs via fluorination of small molecular donors and modulation of crystallinity deviation between donors and acceptors.
关键词： morphology,all-small-molecule organic solar cells,crystallinity,fluorination,orientation modulation
更新于2025-09-12 10:27:22
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Influence of the acceptor crystallinity on the open-circuit voltage in PTB7-Th: ITIC organic solar cells
摘要： The influence of the solution property on both the morphology and the device performance is discussed through various investigation methods based on ITO/ZnO/PTB7-Th: ITIC/MOO3/Ag Organic Solar Cells (OSCs). It is found that the solution component plays an important role in the morphology and the crystallinity of the active layers as confirmed by atomic force microscope (AFM) and grazing incident wide-angle X-ray scattering (GIWAXS), resulting in obviously difference in the open-circuit voltage (VOC) of the devices. The crystallinity of ITIC acceptor in the active layer is further found to correlate with the energy of charge transfer states (CTS) of the devices according to the Electroluminescence (EL) Spectrometry measurements. The CTS energy shift caused by the crystallinity variation is directly related to the enhanced VOC in this study.
关键词： open-circuit voltage,morphology,charge transfer states,crystallinity,organic solar cells
更新于2025-09-12 10:27:22
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Structural characterization of Argania spinosa Moroccan wooden artifacts during natural degradation progress using infrared spectroscopy (ATR-FTIR) and X-Ray diffraction (XRD)
摘要： The present work is focused on spectroscopic study of four samples of Argan wooden artifact pertaining to the 17th, 18th, 20th and 21st centuries. The objective is to characterize their unknown structures by the study of their non degraded parts and to investigate changes occurred in their degraded parts due to the natural degradation process. Attenuated total re?ectance Fourier transform infrared spectroscopy gauges the presence of many functional groups related to cellulose I and/or II (OH, C–O–C and –CH2), hemicelluloses (particularly C?O (cid:2)1), and lignin (OH phenolic, Car-O and C?Car) and provides qualitative information on the state of wood alteration by informing on the evolution of new former C?O bands. The degree of conversion to carbonyl group, especially quinone or p-quinone at 1650 cm (cid:2)1, is correlated to lignin degradation, while the absence of the C?O acetoxy absorption is ascribable to occurred deterioration in hemicelluloses, and (cid:2)1. X-ray diffraction determines the presence of two forms of cellulose; amorphous cellulose at 18.5(cid:3) 2θ and predominant crystalline cellulose Iβ at 2θ ? 22.6(cid:3) which characterized by an intense peak. The decrease of crystallinity index values con?rms the deterioration level and obvious changes in crystallinity level. However, the microcrystalline structure appears unaltered because no signi?cant changes were observed for calculated cristallite seize. The obtained results depend on the prolonged time of ageing, natural deterioration phenomena, and wood part (internal or external) that is exposed to degradation. The combination of these two methods is useful for an accurate estimation of the degradation level of argan wood.
关键词： Chemistry,Argan wood artifact,XRD,Analytical chemistry,Natural product chemistry,Materials Chemistry,Natural degradation,Archaeology,ATR-FTIR spectroscopy,Crystallinity,Lignocelluloses,Structural characterization,Materials Science,Organic chemistry
更新于2025-09-12 10:27:22
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Improved Efficiency in All-Small-Molecule Organic Solar Cells with Ternary Blend of Non-Fullerene Acceptor and Chlorinated and Non-Chlorinated Donors.
摘要： Ternary non-fullerene all-small-molecule organic solar cells (NFSM-OSCs) were developed by incorporating a non-fullerene acceptor (IDIC) and two structurally similar small molecular donors (SM and SM-Cl), where SM-Cl is a novel small molecular donor derived from the reported molecular donor SM. When doping 10% SM-Cl in SM:IDIC binary system, the power conversion efficiency (PCE) of ternary solar cell was dramatically increased from 9.39% to 10.29%. Characterization studies indicated that the two donors tend to form an alloy state, which effectively down-shifted the HOMO energy level of the donor, and thus promoting a higher open-circuit voltage. Interestingly, incorporating a third component (SM-Cl) with lower crystallinity was proven to facilitate the demixing between donors and acceptors, which was in contrary to the traditional findings of enhanced phase separation through incorporation of highly crystalline molecule. Although the morphological modulation had always been a bottleneck issue in NFSM-OSCs, the findings in this work indicated that the modulation on crystallinity deviation between donors and acceptors could be an effective method to further improve the performance of NFSM-OSCs, providing a new perspective on NFSM-OSCs.
关键词： alloy model,non-fullerene all-small-molecule solar cells,chlorinated molecular donor,ternary strategy,crystallinity modulation
更新于2025-09-12 10:27:22
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Influence of Poly(Vinylidene fluoride) on photovoltaic performance of interfacially engineered band gap modulated P3TAA-co-P3HT perovskite solar cell at ambient condition
摘要： Recently, mixing of foreign polymers with perovskite increases light absorption yielding a large increase of power conversion efficiency (PCE) and also increasing longevity of perovskite solar cells (PSCs). The previous studies are limited at dry or at very low humid conditions. Here, for practical use, we report a new series of poly(vinylidene fluoride) (PVDF)- perovskite (MAPbI3) hybrid solar cells made from different PVDF concentrations e.g. 0.0, 0.25, 0.5, 1.0, 2.5, 5.0 mg/ml, and are designated as H1, H2, H3, H4, H5, and H6, respectively. The average grain size, measured from SEM images of MAPbI3 (312±91 nm) has decreased with increasing PVDF concentration showing a minimum (215±43 nm) for H5 sample. UV-Vis absorption spectra show the highest absorption for H5 sample for all the wavelengths. The intensities and width of X-ray diffraction peaks increase in the hybrids (H3 and H5) from pristine perovskite indicating increase of crystallinity and crystalline size. We have used an interfacially engineered, band gap modulated poly(3-thiophene acetic acid)–co-poly(3-hexyl thiohene) P3TTA - co - P3HT, with 43 mol% P3TAA content as hole transporting material (HTM) and TiO2 as electron transporting material (ETM) to fabricate the cell. The PCE, measured on illumination with a light of one sun at ambient condition (humidity 75-85%, temperature 30 oC), is 12 % for H5 PSC, highest reported so far, and it is 20% higher from pristine PSC. The incident photon to current conversion efficiency (IPCE) data exhibit strong absorption in the broad range 300-800 nm showing a maximum IPCE value of 84 %. Impedance spectral data indicate that lifetime of photo-generated charges are highest (48.4 ms) explaining the highest PCE value for H5-PSC compared to other hybrids. The longevity of the H5-PSC is significantly (54%) higher than PSC made with pristine perovskite measured and stored under identical ambient condition.
关键词： perovskite solar cells,crystallinity,grain size,poly(vinylidene fluoride),power conversion efficiency,ambient condition
更新于2025-09-12 10:27:22