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An inverted ZnO/P3HT:PbS bulk-heterojunction hybrid solar cell with a CdSe quantum dot interface buffer layer
摘要： An inverted bulk-heterojunction (BHJ) hybrid solar cell having the structure ITO/ZnO/P3HT:PbS/Au was prepared under ambient conditions and the device performance was further enhanced by inserting an interface buffer layer of CdSe quantum dots (QDs) between the ZnO and the P3HT:PbS BHJ active layer. The device performance was optimized by controlling the size of the CdSe QDs and the buffer layer thickness. The buffer layer, with an optimum thickness and QD size, has been found to promote charge leading to an increased open-circuit voltage (VOC), extraction and reduces interface recombinations, short circuit current density (JSC), fill factor (FF) and power conversion efficiency (PCE). About 40% increase in PCE from 1.7% to 2.4% was achieved by the introduction of the CdSe QD buffer layer, whose major contribution comes from a 20% increase of VOC.
关键词： CdSe quantum dots,inverted bulk-heterojunction,interface buffer layer,hybrid solar cell,power conversion efficiency
更新于2025-09-23 15:21:01
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Understanding the effect of solvent additive in polymeric thin film: turning a bilayer in a bulk heterojunction like photovoltaic device
摘要： Here we report the effect of an additive solvent, the 1,8-diiodooctane (DIO) on the performance of a bilayer organic photovoltaic (OPV) device which active layer comprises the poly[2,7-(9,9-bis(2 ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PSiF-DBT) as the electron donor material and C60 as the electron acceptor material. We observed that when the donor layer was treated with 1% of DIO the power conversion efficiency (PCE) of the device increase 138.4% in relation to the device with a non-treated donor layer and 21.3% in relation to the device containing a donor layer submitted to a thermal annealed. The main effects that lead to this increase in PCE are the large interfacial area between donor and acceptor materials and the improved conductivity at low voltages. The increase in polymer surface roughness leads to a more effective PSiF-DBT/C60 interface for exciton dissociation. This effect, as well as the increase in the conductivity, raised the short circuit current density (JSC) to 13.89 mA/cm2 and PCE to 4.84%. Our conclusions are supported by morphological analysis, chemical cross-sectional evaluations with advanced microscopy techniques, charge mobility measurements as well as by theoretical simulations of the devices in which the changes on the donor/acceptor interfacial area were considered. The outcomes suggest that, solvent additives could be an alternative treatment to replace the thermal annealing which imposes further difficulties to perform the lab-to-manufacturing upscaling.
关键词： solvent additive,PSiF-DBT,exciton dissociation,1,8-diiodooctane,C60,organic photovoltaic,power conversion efficiency
更新于2025-09-23 15:21:01
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Single-Junction Organic Photovoltaic Cells with Approaching 18% Efficiency
摘要： Optimizing the molecular structures of organic photovoltaic (OPV) materials is one of the most effective methods to boost power conversion efficiencies (PCEs). For an excellent molecular system with a certain conjugated skeleton, fine tuning the alky chains is of considerable significance to fully explore its photovoltaic potential. In this work, the optimization of alkyl chains is performed on a chlorinated nonfullerene acceptor (NFA) named BTP-4Cl-BO (a Y6 derivative) and very impressive photovoltaic parameters in OPV cells are obtained. To get more ordered intermolecular packing, the n-undecyl is shortened at the edge of BTP-eC11 to n-nonyl and n-heptyl. As a result, the NFAs of BTP-eC9 and BTP-eC7 are synthesized. The BTP-eC7 shows relatively poor solubility and thus limits its application in device fabrication. Fortunately, the BTP-eC9 possesses good solubility and, at the same time, enhanced electron transport property than BTP-eC11. Significantly, due to the simultaneously enhanced short-circuit current density and fill factor, the BTP-eC9-based single-junction OPV cells record a maximum PCE of 17.8% and get a certified value of 17.3%. These results demonstrate that minimizing the alkyl chains to get suitable solubility and enhanced intermolecular packing has a great potential in further improving its photovoltaic performance.
关键词： nonfullerene acceptors,organic photovoltaic cells,molecular modification,power conversion efficiency
更新于2025-09-23 15:21:01
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Tweaking the physics of interfaces between monolayers of buckled cadmium sulfide for a superhigh piezoelectricity, excitonic solar cell efficiency and thermoelectricity
摘要： Interfaces of heterostructures are routinely studied for different applications. Interestingly, monolayers of the same material when interfaced in an unconventional manner can bring about novel properties. For instance, CdS monolayers, stacked in a particular order, are found to show unprecedented potential in the conversion of nanomechanical energy, solar energy and waste heat into electricity, which has been systematically investigated in this work, using DFT based approaches. Moreover, stable ultrathin structures showing strong capabilities for all kinds of energy conversion are scarce. The emergence of a very high out-of-plane piezoelectricity, |d33| ~ 56 pm/V, induced by the inversion symmetry broken in the buckled structure helps to supersede the previously reported bulk wurzite GaN, AlN and Janus multilayer structures of Mo and W based dichalcogenides. The piezoelectric coefficients have been found to be largely dependent on the relative stacking between the two layers. CdS bilayer is a direct band gap semiconductor with its band edges straddling the water redox potential, thereby making it thermodynamically favorable for photocatalytic applications. Strain engineering facilitates its transition from type-I to type-II semiconductor in CdS bilayer stacked over monolayer boron phosphide, and the theoretically calculated power conversion efficiency (PCE) in the 2D excitonic solar cell exceeds 27% for a fill factor of 0.8, which is much higher than that in ZnO/CdS/CuInGaSe solar cell (20% efficiency). Thermoelectric properties have been investigated using semi classical Boltzmann transport equations for electrons and phonons within the constant relaxation time approximation coupled to deformation potential theory, which reveal ultralow thermal conductivity (~ 0.78 Wm-1K-1) at room temperature due to the presence of heavy element Cd, strong anharmonicity (high mode Gruneisen parameter at long wavelength, phonon lifetime < 5 ps), low phonon group velocity (4 km/s) and low Debye temperature (260 K). Such a low thermal conductivity is lower than that of dumbbell silicene (2.86 Wm-1K-1), SnS2 (6.41 Wm-1K-1) and SnSe2 (3.82 Wm-1K-1), SnP3 (4.97 Wm-1K-1). CdS bilayer shows a thermoelectric figure of merit (ZT) ~ 0.8 for p-type and ~ 0.7 for n-type doping at room temperature. Its ultrahigh carrier mobility (μe ~2270 cm2V-1s-1) is higher than that of single layer MoS2 and comparable to that in InSe. The versatile properties of CdS bilayer together with its all-round stability supported by ab initio molecular dynamics simulation, phonon dispersion and satisfaction of Born-Huang stability criteria highlight its outstanding potential for applications in device fabrication and applications in next generation nanoelectronics and energy harvesting.
关键词： Power conversion efficiency,Excitonic solar cell,Piezoelectricity,Photocatalysis,Solar energy,Semiconductor,Thermoelectricity,Carrier mobility
更新于2025-09-23 15:21:01
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Silicon nanocrystal hybrid photovoltaic devices for indoor light energy harvesting
摘要： Silicon nanocrystals (SiNCs) featuring size-dependent novel optical and electrical properties have been widely employed for various functional devices. We have demonstrated SiNC-based hybrid photovoltaics (SiNC-HPVs) and proposed several approaches for performance promotion. Recently, owing to the superiorities such as low power operation, high portability, and designability, organic photovoltaics (OPVs) have been extensively studied for their potential indoor applications as power sources. SiNCs exhibit strong light absorption below 450 nm, which is capable of sufficient photocurrent generation under UV irradiation. Therefore, SiNC-HPVs are expected to be preferably used for energy harvesting systems in indoor applications because an indoor light source consists of a shorter wavelength component below 500 nm than solar light. We successfully demonstrated SiNC-HPVs with a PCE as high as 9.7%, corresponding to the output power density of 34.0 mW cm?2 under standard indoor light irradiation (1000 lx). In addition, we have found that SiNC defects working as electron traps influence the electrical properties of SiNCs substantially, a thermal annealing process was conducted towards the suppression of defects and the improvement of the SiNC-HPVs performance.
关键词： Silicon nanocrystals,Power conversion efficiency,Indoor light energy harvesting,Thermal annealing,Hybrid photovoltaics
更新于2025-09-23 15:21:01
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Improving the performance of Cu2ZnSnS4 thin film solar cell by engineering the ITO film thickness
摘要： In this work, the effects of tin doped indium oxide (ITO) thin films with different thicknesses (50 nm–476 nm) on the optoelectronic performance were investigated. Meanwhile, the sputtered ITO layers were annealed at 180°C for 60min under air atmosphere. The result indicated that the electro-optical properties of ITO films with the thickness (383 nm) were optimum, and the corresponding resistivity and average reflectance in the spectrum range (350–860 nm) were 4.73 × 10?4 Ω cm and lower than 20%, respectively. Finally, impacts of ITO layers with various thicknesses on the performance of CZTS solar cells were also studied. The open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and power conversion efficiency (PCE) of CZTS solar cells had been increased significantly from 576 mV to 636 mV, from 15.8 mA/cm2 to 20.2 mA/cm2, from 31.2% to 43.4% and from 3.04% to 5.56%, respectively, and eventually the highest PCE of CZTS solar cell based on 383 nm ITO window layer thickness was 5.56%.
关键词： Power conversion efficiency,ITO films,Reflectance,Optoelectronic performance
更新于2025-09-23 15:21:01
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Structure-Property Correlation Study for Organic Photovoltaic Polymer Materials Using Data Science Approach
摘要： A study workflow that utilizes several data science methods to apply on polymer materials databases is introduced to reveal correlations among their properties, structural information, or molecular descriptors. The data science methods used in this pipeline include unsupervised machine learning (ML) method self-organizing mapping (SOM) and polymer molecular descriptor generator, both of which have been tailored to fit the polymer materials study. To demonstrate how this pipeline can be applied in this context, we used it on an organic photovoltaic (OPV) donor polymer database to investigate which properties or structural factors positively correlate with the power conversion efficiency (PCE) of OPV materials. This led us to discover that among the studied 8 properties and 11 molecular descriptors, only the photon energy loss (Eloss) and the number of fluorine atoms (nF) show strong positive correlations with PCE values, which is consistent with other verified studies. We also discovered that research trends can also be statistically visualized using our method. In our case study, we found that most of the studied OPV donor materials in the database have branched side chains and typically 7 to 12 non-Hydrogen atoms, and high PCE materials usually have 6 to 9 aromatics rings as well. These results proved that the data science pipeline proposed in this study provides a fast and effective way to obtain research insights for polymer materials.
关键词： self-organizing mapping,data science,molecular descriptors,polymer materials,organic photovoltaic,power conversion efficiency
更新于2025-09-23 15:21:01
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Carbazole Green and Blue-BODIPY Dyads and Triads as Donors for Bulk Heterojunction Organic Solar Cells
摘要： Two BODIPY derivatives with one (B2) and two (B3) carbazole moieties were designed, synthesized and applied as electron-donor materials in organic photovoltaic cells (OPV). The optical and electrochemical properties were systematically investigated. These BODIPY dyes exhibit excellent solubility in organic solvents and present high molar extinction coefficients (1.37–1.48 x 105 M-1 cm-1) in solutions with absorption maxima at 586 nm for mono-styryl group and at 672 nm for di-styryl groups. The introduction of the styryl moieties result in a large bathochromic shift and a significant decrease in the HOMO-LUMO energy-gaps. The BODIPY dyes show relatively low HOMO energies ranging from -4.99 to -5.16 eV as determined from cyclic voltammetry measurements. Cyclic voltammetry measurements and theoretical calculations demonstrate that the frontier molecular orbital levels of these compounds match with PC71BM as the acceptors, supporting their application as donor materials in solution-processed small molecule bulk heterojunction (BHJ) organic solar cells. After the optimization of the active layer, B2:PC71BM and B3:PC71BM based organic solar cells showed the overall power conversion efficiency of 6.41% and 7.47%, respectively. The higher PCE of B3 based OSC is ascribed to the more balanced charge transport and exciton dissociation, better crystalline and molecular packing.
关键词： bulk heterojunction,Green and blue-BODIPY,electrochemistry,power conversion efficiency
更新于2025-09-23 15:21:01
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Readily Accessible Benzo[d]thiazole Polymers for Nonfullerene Solar Cells with >16% Efficiency and Potential Pitfalls
摘要： Here we report facile, high-yield synthetic access to the difluoro BTA building block, 4,7-bis(5-bromo-4-(2-hexyl-decyl)-thiophen-2-yl)-5,6-difluoro-2-(pentadecan-7-yl)-benzo[d]thiazole (BTAT-2f) for use in Donor (D)-Acceptor 1(A1)-D-Acceptor 2(A2) polymers [D = bithiophene, A1 = BTA-2f, A2 = benzothiadiazole (BT) derivative] for organic solar cells (OSCs). Fine tuning of polymer optical and electronic properties is achieved by incrementally varying the A2 fluorination level. Bulk-heterojunction (BHJ) PBTATBT-4f:Y6 solar cells deliver a noteworthy power conversion (PCE) efficiency of 16.08 % (Voc =0.81 V, Jsc =27.25 mAcm-2, FF =72.70 %) without processing additives. In contrast, PBTATBT-2f:Y6 exhibits an irregular morphology and low PCE, ascribable to co-crystal formation-induced recombination, which is unprecedented for non-fullerene (NFA) OSCs. This result should be of guiding significance for future NFA design.
关键词： Benzo[d]thiazole Polymers,Power Conversion Efficiency,Organic Solar Cells,Co-crystal Formation,Nonfullerene Solar Cells
更新于2025-09-23 15:21:01
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A Review: Crystal Growth for High-Performance All-inorganic Perovskite Solar Cells
摘要： Recently, halide perovskites have become one of the most promising materials for solar cells owing to their outstanding photoelectric performance. Among them, metal halide all-inorganic perovskites (CsPbX3; where X denotes a halogen) show superior thermal and light stability. In particular, the power conversion efficiency (PCE) of perovskite solar cells (pero-SCs) based on a CsPbX3 active layer has shown a steady increase from 2.7% to 19.03% with the improvement of the CsPbX3 crystal quality. In this review, we summarize methodologies that have been employed for controlling the growth of all-inorganic perovskite films so far, including precursor solution deposition, substrate modification, composition doping, and surface engineering. Furthermore, we discuss the effect of perovskite crystal characteristics on defects and perovskite film morphology, both of which are closely related to device performance. Finally, conclusions and perspectives are presented along with useful guidelines for developing all-inorganic pero-SCs with high PCE and robust stability.
关键词： light stability,halide perovskites,precursor solution deposition,all-inorganic perovskites,surface engineering,substrate modification,thermal stability,power conversion efficiency,CsPbX3,composition doping,solar cells,crystal growth
更新于2025-09-23 15:21:01