- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effects of fluorination and thermal annealing on charge recombination processes in polymer bulk-heterojunction solar cells
摘要： We investigate the effect of fluorination on the photovoltaic properties of an alternating conjugated polymer composed of 4,8-di-2-thienylbenzo[1,2-b:4,5-b0]dithiophene and 4,7-bis([2,20-bithiophen]-5-yl)-benzo-2-1-3-thiadiazole (4TBT) units in bulk-heterojunction solar cells. The unsubstituted and fluorinated polymers afford very similar open-circuit voltages and fill factor values, but the fluorinated polymer performed better due to enhanced aggregation which provides a higher photocurrent. The photovoltaic performance of both materials improved upon thermal annealing at 150–200 °C as a result of a significantly increased fill factor and open-circuit voltage, counteracted by a slight loss in photocurrent. Detailed studies of the morphology, light intensity dependence, external quantum efficiency and electroluminescence allowed the exploration of the effects of fluorination and thermal annealing on the charge recombination and the nature of the donor–acceptor interfacial charge transfer states in these films.
关键词： polymer bulk-heterojunction solar cells,thermal annealing,charge recombination,fluorination,photovoltaic properties
更新于2025-10-22 19:40:53
-
Quantum chemical investigation of modified coumarin-based organic efficient sensitizers for optoelectronic applications
摘要： One of the most major features in the improvement of dye-sensitized solar cells (DSSCs) is the survey and plan of high-efficiency and low-cost dyes. In this paper, a new series of metal-free coumarin-based (NKX-2311) dye molecules, namely (D1–D4) are investigated for use in DSSC applications. The dye molecules contain three parts, electron-donor (D) connected by the π-conjugated linker as a spacer and electron-acceptor (A)/anchoring group. Molecular structure, electronic absorption spectra and photovoltaic (PV) parameters of the D1–D4 dyes have been performed by using density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches are employed. The effects of chemical modification on the spectra and PV properties of the coumarin-modified organic dyes have been revealed. The performance of three functionals (B3LYP, CAM-B3LYP and ωB97XD) has been evaluated to get an experimental absorption wavelength of NKX-2311. From the functionals, B3LYP method was better matched with the absorption wavelength of NKX-2311. Therefore, D1–D4 dye molecules excited state calculations of the absorption spectra have been investigated by using B3LYP functional with 6-31G(d) basis set. The results show that D1, D3 dyes are smaller energy gap and absorption spectra are systematically red-shifts. The theoretical results have a display that the lowest occupied molecular orbitals (LUMOs) and highest occupied molecular orbitals (HOMOs) of the D1–D4 dyes can be confirming positive response on the electron injection and dye regeneration process. The NLO property of the D1–D4 dyes can be derived as polarizability and first-order hyperpolarizability. The calculated values of D1 and D3 dyes are the best applicants for NLO performance. The conclusion of this study will deliver a useful reference to the future proposal and beneficial to get DSSCs with superior power conversion efficiency (PCE).
关键词： TD-DFT,coumarin-based dyes,DSSCs,NLO properties,DFT,photovoltaic properties
更新于2025-09-23 15:21:01
-
Enhancement in Photovoltaic Properties of <i>N</i> , <i>N</i> a??diethylaniline based Donor Materials by Bridging Core Modifications for Efficient Solar Cells
摘要： The increasing demand of energy expedited the development of efficient photovoltaic materials.Herein, five push-pull donor materials (D1-D5) having N,N-diethylaniline as donor moiety and rhodanine-3-acetic as acceptor group are designed to be used as donor molecules in organic solar cells (OSCs). The bridging core modification of recently synthesized MR3 molecule (reference R) has been made with different π-spacers namely thiazole (B1), thieno[3,2-b]thiophene (B2), thiazolo[5,4-d] thiazole (B3), 2-(thiophen-2-yl)thiophene (B4) and 5-(thiazol-5yl)thiazole (B5). The structure–property relationship is studied and influence of bridging core modifications on photovoltaic, photophysical and electronic properties of D1-D5 are calculated and compared with reference R.The DFT and TDDFT calculations have been performed for the estimation of frontier molecular orbital (FMO) analysis, density of states (DOS) graphs, reorganization energies of electron and hole, open circuit voltage, photophysical characteristics, transition density matrix (TDM) surfaces and charge transfer analysis.Designed molecules exhibit better and comparable optoelectronic properties than synthesized reference molecules. Among all investigated molecules, D5 is proven as best candidate for OSCs application due to its promising photovoltaic properties including lowest band gap (2.24 eV), small electron mobility (λe = 0.0056 eV), small hole mobility (λh = 0.0046 eV), low binding energy (Eb = 0.21 eV), highest λmax values 610.76 nm (in gas) 670.22 nm (in acetonitrile) and high open circuit voltage (Voc = 1.17 V) with respect to HOMOdonor–LUMOPC61BM. This theoretical framework demonstrates that bridging core modification is a simple and effective alternative strategy to achieve the desirable optoelectronic properties. Furthermore, conceptualized molecules are superior and thus are recommended to experimentalist for out-looking future developments of highly efficient solar cells.
关键词： Rhodanine-3-acetic acid,Solar cells,Photovoltaic properties,Bridging core modifications,Density functional theory (DFT),N,N-diethylaniline
更新于2025-09-23 15:21:01
-
Effects of annealing temperature on photovoltaic properties of lead-free (CH<sub>3</sub>NH<sub>3</sub>)<sub>3</sub>Bi<sub>2</sub>I<sub>9</sub> solar cells
摘要： Effects of annealing temperature on photovoltaic properties of lead-free (CH3NH3)3Bi2I9 solar cells were investigated. The (CH3NH3)3Bi2I9 photovoltaic cells were fabricated by a hot air blow-assisted spin-coating method. The spin-coated (CH3NH3)3Bi2I9 photoactive layers were annealed at temperatures of 100–150 °C. Current density–voltage characteristics of the (CH3NH3)3Bi2I9 photovoltaic cells showed that conversion efficiency increased with increasing annealing temperature. Microstructures and optical properties of the (CH3NH3)3Bi2I9 photoactive layers were also investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and ultraviolet–visible–near infrared spectroscopy. The investigation revealed that the changes in lattice constants, crystallite size, surface morphology, and iodide/bismuth ratio of the (CH3NH3)3Bi2I9 were attributed to the annealing temperature, resulting in the changes in the photovoltaic properties of the (CH3NH3)3Bi2I9 solar cells.
关键词： Solar cells,(CH3NH3)3Bi2I9,Annealing temperature,Photovoltaic properties
更新于2025-09-23 15:21:01
-
Designing indenothiophene-based acceptor materials with efficient photovoltaic parameters for fullerene-free organic solar cells
摘要： Non-fullerene small molecular acceptors (NFSMAs) exhibit promising photovoltaic performance which promoted the rapid progress of organic solar cells (OSCs). In this study, an attempt is done to explore indenothiophene-based high-performance small molecular electron acceptors for organic solar cells. We have designed five acceptor molecules (M1–M5) with strong donor moiety indenothiophene linked to five different end-capped group acceptor moieties: diflouro-2-methylene-3-oxo-2,3-dihydroindene-1-ylidene)malononitrile (A1), 1-(dicyanomethylene)-2-methylene-3-oxo-2,3-dihydro-1H-indene-5,6-dicarbonitrile (A2), methyl-6-cyano-3-(dicyanomethylene)-2-methylene-1-oxo-2,3-dihydro-1H-indene-5-carboylate (A3), 2-(6-cyano-5-fluoro-2-methylene-3-oxo-2,3 dihydro-1H-indene-1-ylidene)malononitrile (A4), and (Z)-methyl 3-(benzo [c][1,2,5]thiadiazol-4-yl)-2-cyanoacrylate (A5) respectively. The structure–property relationship was studied and effects of structural modification on the optoelectronic properties of these acceptors (M1–M5) were determined systematically by comparing it with reference molecule R, which is recently reported as excellent non-fullerene-based small acceptor molecule. Among all designed molecules, M5 is proven as a suitable candidate for organic solar cell applications due to better photovoltaic properties including narrow HOMO-LUMO energy gap (2.11 eV), smallest electron mobility (λe = 0.0038 eV), highest λmax values (702.82 nm in gas) and (663.09 nm in chloroform solvent) and highest open-circuit voltage (Voc = 1.49 V) with respect to HOMOPTB7-Th–LUMOacceptor. Our results indicate that introducing more end-capped electron-accepting units is a simple and effective alternative strategy for the design of promising NFSMAs. This theoretical framework also proves that the conceptualized NFSMAs are superior and thus are recommended for the future construction of high-performance organic solar cell devices.
关键词： Photovoltaic properties,Indenothiophene,Density functional theory (DFT),Non-fullerene acceptor materials,Organic solar cells (OSCs)
更新于2025-09-23 15:21:01
-
Superior ferroelectric photovoltaic properties in Fe -modified (Pb,La) (Zr,Ti)O3 thin film by improving the remnant polarization and reducing the band gap
摘要： In order to develop ferroelectric photovoltaic devices with high power conversion e?ciency, ferroelectric materials must have simultaneously large remnant polarization and narrow band gap so as to e?ciently separate photo-generated carriers and absorb more sunlight. Based on this idea, in this report, we introduce Fe3+ into Pb0·93La0·07(Zr0·6Ti0.4)0.9825O3 ferroelectric thin ?lm to increase the remnant polarization and decrease the band gap of the thin ?lm. In doing so, we prepare Fe3+ doping Pb0·93La0·07(Zr0·6Ti0.4)0.9825O3 thin-?lm based photovoltaic devices. The experimental results indicate that with increasing the Fe3+ amount, the remnant polarization of the ?lm ?rst improves to the maximum value of 50 μC/cm2 at the 4.8 mol% Fe3+ content and then reduces gradually, while the band gap continuously decreases. In addition, at a negative poling voltage, the device exhibits larger short-circuit current and open-circuit voltage in comparison with those obtained at the positive poling voltage, which is attributed to the depolarization electric ?eld originating from the remnant polarization of ferroelectric thin ?lms in the same direction as the built-in electric ?eld caused by the Schottky barrier. In this report, the most superior photovoltaic performances with the open-circuit voltage of as large as ?0.55 V and short-circuit current of as high as 0.4 μA/cm2 are obtained in the device with 4.8 mol% Fe3+ amount and at ?5 V poling voltage. This is on account of the improved sunlight absorbing properties and photo-generated carriers separation ability of the device. This work provides a novel idea for designing and preparing ferroelectric photovoltaic devices with high power conversion e?ciency.
关键词： Fe3+ doping,Photovoltaic properties,Band gap,Remnant polarization,Ferroelectric thin ?lm
更新于2025-09-23 15:21:01
-
Design and Synthesis of the Da????a??A-Structured Coadsorbents with the Phenanthraquinone Core and Its Application in Dye-Sensitized Solar Cells
摘要： Highly efficient different co-adsorbents using phenanthraquinone coupled with benzene/naphthalene as donor (D), benzene act as π-spacer (π) and variation in acceptor (A) like aromatic/aliphatic OH, COOH, triazole based derivatives were synthesized. These eight D-π-A based co-absorbents are effectively examined for their application in dye-sensitized solar cell (DSSC). The presence of hetero atoms and dense conjugated system paved a way for the hole mobility and in the rise of organic photovoltaic properties. Both the electrochemical and photovoltaic data gradually supported the studies by using I-/I3 - redox shuttle based electrolyte. Results from impedance, FTIR, UV, binding energy and HOMO-LUMO band gap calculations from density functional theory (DFT) were analysed to figure out the mechanistic way of our device. The TiO2 working electrode with N719 dye and synthesized CA-2 with iodolyte Z-50 as electrolyte has the highest PCE as 6.33% under an illumination of 100mW/cm2.
关键词： Photovoltaic properties,Co-adsorbents,Phenanthraquinone,D-π-A structure,Dye-sensitized solar cells
更新于2025-09-23 15:19:57
-
Predicting Device Parameters for Dye-Sensitized Solar Cells from Electronic Structure Calculations to Reproduce Experiment
摘要： Given that improvements to power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs) have slowed in recent years, a means to accurately predict device parameters yielded by trial dyes in silico, without having to synthesize them, would be extremely valuable to speed up the design process. Currently, the best performing methods of calculating device parameters rely on a set of experimentally determined kinetic coefficients. In practice, it is very difficult to measure these kinetic parameters accurately, limiting the overall accuracy of such predictive methods. This work proposes a model to obtain key parameters such as JSC, VOC and PCE using only results from density functional theory (DFT) and time-dependent DFT calculations, noting that rates of electron transfer steps are ultimately linked to the electronic structure of the dye…TiO2 working electrode. Six organic DSSC dyes from dissimilar chemical classes (L0, L1, L2, WS-2, WS-92 and C281) were chosen to demonstrate the power of this approach. Their a priori known experimentally determined device performance metrics served to validate our predictions. The greatest absolute error in our predicted PCE values was 0.36% relative to experiment, whilst the greatest fractional error was 0.042. This indicates the proposed model offers a dramatic improvement on previous predictive methods for DSSC device parameters, both in accuracy and consistency. Moreover, the spirit of designing such a predictive model has great potential to be applied to other photovoltaic applications, further enabling the design of novel, highly efficient photoactive materials.
关键词： performance prediction,energy-conversion efficiency,dye-sensitized solar cells,photovoltaic properties,density functional theory
更新于2025-09-23 15:19:57
-
A Comparative Study on the Photovoltaic Properties of ZnX (X=S, Se, Te) QD/CNT Inorganic/Organic Hybrid Nanocomposites
摘要： Designing the efficient inorganic/organic hybrid light harvesting systems through understanding of charge generation, separation and recombination dynamics is an important pathway for improvement of power conversion efficiency (PCE) of photovoltaic cell. Using density functional method, we explored the photovoltaic performance of recently synthesized ZnX (X=S, Se, Te) QD/carbon nanotube (CNT) nanocomposites. Interestingly, ZnX QD/CNT nanocomposites exhibit type-II band alignment, where hole and electron charge carriers are localized on ZnX QD and CNT, respectively. However, the energy difference between highest occupied molecular orbital of ZnXQD and conduction band minimum of CNT is very small (0.09-0.26 eV), implying huge possibilities of electron-hole recombination at ZnX:CNT interface. To overcome such unpleasant situation, we focus on chemical modification of CNT. The CNT is hydrogenated by attachment of atomic hydrogen and next the hydrogenated CNT is functionalized by electron withdrawing group (-CN) in part. We found that ZnX QD and CN functionalized hydrogenated CNT nanocomposites exhibit intended type-II band alignment and achieve high PCEs in the range of 6.73-8.38%, making them exceptionally competitive with other previously reported hybrid solar cells.
关键词： inorganic/organic hybrid nanocomposites,power conversion efficiency,ZnX QD/CNT,type-II band alignment,photovoltaic properties
更新于2025-09-23 15:19:57
-
Theoretical study on photoelectric properties of lead-free mixed inorganic perovskite RbGe1-xSnxI3
摘要： The recent discoveries of lead-free halide perovskites have come into notice as promising photovoltaic materials due to their high solar-to-electrical efficiency conversion. However, these perovskites suffer from large effective masses, wide band gap and affected photovoltaic performance. It is well known that it is an effective means to overcome the above shortcomings by changing the metallic ion concentration and position for the inorganic perovskite. Herein, we study the geometrical, electronic, and optical properties of RbGe1-xSnxI3 with various compositions of metal atoms by performing the Density Functional Theory (DFT). Besides, we systematically investigate how the doping positions of stannum (Sn) atoms affect the electronic structure by taking mixed metal RbGe0.50Sn0.50I3 compound as an example. The results show that RbGe1-xSnxI3 exhibits the semiconducting property with the tunable direct band gaps by changing its proportions. Compared to other two doping positions in the perovskite RbGe0.50Sn0.50I3, the configuration with Sn atom at equator plane has better mobility of electron and optical absorption properties. Our works demonstrate that the modification of metal concentration and position will modulate the optoelectronic performance and photovoltaic properties of mixed metal perovskites.
关键词： RbGe1-xSnxI3,photovoltaic properties,Sn-doped,doping positions
更新于2025-09-23 15:19:57