- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effects of non-halogenated solvent on the main properties of a solution-processed polymeric thin film for photovoltaic applications: a computational study
摘要： Organic photovoltaic (OPV) devices reached high solar conversion efficiencies but they are usually processed using halogenated toxic solvents. Hence, before OPV devices can be mass-produced by industrial processing, it would be desirable to replace those solvents with eco-friendly ones. Theoretical tools may be then a powerful ally in the search for those new solvents. In order to better understand the mechanisms behind the interaction between solvent and polymer, classical molecular dynamics (MD) calculations was used to produce a thin film of poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl (PTB7-Th), processed using two different solvents. The PTB7-Th is widely applied as a donor material in OPVs. The first solvent is the ortho-dichlorobenzene (o-DCB), which is a highly toxic solvent widely used in lab-scale studies. The second solvent is the ortho-methylanisole (o-MA), which is an eco-friendly solvent for organic photovoltaic (OPV) manufacturing. Here we use a solvent evaporation protocol to simulate the formation of the PTB7-Th film. We demonstrate that our theoretical MD calculations were able to capture some differences in macroscopic properties of thin films formed by o-DCB or o-MA evaporation. We found that the interaction of the halogenated solvent with the polymer tends to break the bonds between the lateral thiophenediyl groups and the main chain. We show that those defects may create traps that can affect the charge transport and also can be responsible for a blue shift in the absorption spectrum. Using the Monte Carlo method, we also verified the influence of the resulting MD morphology on the mobility of holes. Our theoretical results showed a good agreement with the experimental measurements and both demonstrate that o-MA can be used to make polymer thin films without any loss of key properties for the device performance. The findings here highlights the importance of theoretical results as a guide to the morphological optimization of green processed polymeric films.
关键词： Solvent evaporation,PTB7-Th,Molecular dynamics,Organic photovoltaic,Halogenated solvents,Eco-friendly solvents,Hole mobility
更新于2025-09-23 15:19:57
-
Full Efficiency Recovery in Hole-Transporting Layer-Free Perovskite Solar Cells With Free-Standing Dry-Carbon Top-Contacts
摘要： Carbon-based top electrodes for hole-transporting-layer-free perovskite solar cells (PSCs) were made by hot press (HP) transfer of a free-standing carbon-aluminum foil at 100?C and at a pressure of 0.1 MPa on a methylammonium lead iodide (MAPbI3) layer. Under these conditions, the perovskite surface was preserved from interaction with the solvent. Over a timescale of 90 days, HP-PSCs were systematically compared to reference cells with carbon-based top electrodes deposited by doctor blading (DB). We found that all the photovoltaic parameters recorded in HP-PSCs during time under ambient conditions settled on values systematically higher than those measured in the reference DB-PSCs, with ef?ciency stabilized at around 6% within the ?rst few measurements. On the other hand, in DB-PSCs, a long-lasting (～14 days) degrading transient of the performances was observed, with a loss of ef?ciency from an initial ～8% to ～3%. Moreover, in HP-PSCs, a systematic day-by-day recovery of the ef?ciency after operation was observed (1～2%) by leaving the cell under open circuit, a nitrogen environment, and dark conditions. Noteworthily, a full recovery of all the parameters was observed at the end of the experiment, while DB-PSCs showed only a partial recovery under the same conditions. Hence, the complete release of solvent from the carbon contact, before an interface is established with the perovskite layer, offers a de?nite advantage through the long period of operation in preventing irreversible degradation. Our ?ndings indeed highlight the crucial role of the interfaces and their feasible preservation under nitrogen atmosphere.
关键词： durability,healing,self-curing,MAPbI3,solvent-free,stability,nitrogen
更新于2025-09-23 15:19:57
-
Non-halogenated solvent-processed ternary-blend solar cells via alkyl-side-chain engineering of a non-fullerene acceptor and its application in large-area devices
摘要： A novel asymmetric non-fullerene acceptor (T2-OEHRH) with a simple chemical structure is designed and synthesized. Compared with the symmetric T2-ORH, T2-OEHRH effectively suppresses excessive self-aggregation/crystallization and substantially improves the solubility without sacrificing photoelectrical properties. As a result, T2-OEHRH-based ternary-blend OSCs processed from a non-halogenated solvent exhibit impressive PCEs of 12.10% and 9.32% in small- and large-area devices, respectively.
关键词： non-fullerene acceptor,large-area solar cells,ternary-blend solar cells,non-halogenated solvent,asymmetric alkyl side-chain
更新于2025-09-23 15:19:57
-
Ultrafast spectroscopic investigation of the effect of solvent additives on charge photogeneration and recombination dynamics in non-fullerene organic photovoltaic blends
摘要： The PBDB-TF:IT-4F blend is a kind of state-of-the-art non-fullerene photovoltaic blend. Herein, the effects of 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) additives on the neat and blend film morphologies and the related ultrafast photophysical processes are studied. It is found that both DIO and CN can lead to an enhanced structural order in the in-plane direction and increased average lifetime of excitons in neat PBDB-TF films. The face-on orientation of PBDB-TF still exists in the DIO-processed PBDB-TF:IT-4F blend film, while in the case of the CN-processed blend film, molecular packing orientation is similar to that of the pristine blend film. The blend samples prepared with the two additives show increased initial exciton yields. Interestingly, in the blend samples prepared with the DIO additive, the recombination loss via the formation of polymer triplet excitons can be effectively suppressed, in comparison to the pristine and CN-processed samples. Both the DIO- and CN-processed devices show increased short-circuit current densities. The DIO-processed device is also found to have a superior fill factor due to suppressed recombination loss. The work provides a comprehensive insight into the ultrafast photophysical processes in varied blend morphologies induced by additives and their effect on the photovoltaic parameters of the devices.
关键词： charge photogeneration,ultrafast spectroscopy,recombination dynamics,solvent additives,non-fullerene photovoltaic blend
更新于2025-09-23 15:19:57
-
Solution-processed blue quantum-dot light-emitting diodes based on double hole transport layers: Charge injection balance, solvent erosion control and performance improvement
摘要： Solution processed quantum-dot based light emitting diodes (QLEDs) usually suffer from the issues of imbalanced carrier injection (especially for blue QLEDs) and solvent erosion, which prevents these devices from reaching high performance. Here we report a simple and effective method of promoting hole injection and mitigating solvent erosion simultaneously for fabricating high-performance blue QLEDs. Poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(p-butylphenyl))-diphenylamine)] (TFB)/Lithium bis(trifluoromethanesulfonimide) (Li-TFSI)-doped poly(9-vinlycarbazole) (PVK) bi-layers with smooth surfaces/interfaces, prepared via a solution-process by utilizing 1,4-dioxane as the solvent for PVK, were used as hole transport layers (HTLs) for improving the performance of blue QLEDs. The TFB/Li-doped PVK based QLED records 5829 cd/m2 of maximum brightness and 5.37% of peak EQE, which represents 1.1-fold increase in brightness and ~11.5-fold increase in EQE as compared with the devices based on TFB-only HTLs. The enhanced performance for these TFB/Li-doped PVK based QLEDs can be ascribed to more efficient hole injection offered by Li-doped bilayer HTLs with smooth surfaces/interfaces and stepwise energy level alignment. The CIE 1931 color coordinates (0.15, 0.03) for these TFB/Li-doped PVK based QLEDs are close to the National Television System Committee (NTSC) standard blue CIE coordinates, showing promise for use in next-generation full-color displays. This work provides a facile solution method of fabricating TFB/Li-doped PVK bi-layers with smooth surfaces/interfaces and proves the superiority of these TFB/Li-doped PVK bi-layered HTLs in hole transport and injection for high-performance blue QLEDs.
关键词： double hole transport layers,blue quantum-dot light-emitting diodes,charge injection；Lithium salt doped hole transport layer,solvent erosion,solution processability
更新于2025-09-23 15:19:57
-
Realizing 22.3% EQE and 7-Fold Lifetime Enhancement in QLED: via Blending Polymer TFB and Cross-linkable Small Molecule for Solvent-Resistant Hole Transport Layer
摘要： Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4'-(N-(4-butylphenyl))] (TFB) has been widely used as a hole transport layer (HTL) material in cadmium-based quantum dots light-emitting diodes (QLEDs) due to its high hole mobility. However, as the highest occupied molecular orbital (HOMO) energy level of TFB is -5.4 eV, the hole injection from TFB to quantum dots (QDs) layer is higher than 1.5 eV. Such high oxidation potential at the QD/HTL interface may seriously degrade the device lifetime. In addition, TFB is not resistant to most solvents, which limits its application in inkjet-printed QLEDs display. In this study, blended HTL consisting of TFB and cross-linkable small molecular 4,4 ′ -bis(3-vinyl-9H-carbazol-9-yl)1,1 ′ -biphenyl (CBP-V) was introduced into red QLEDs, because of the deep HOMO energy level of CBP-V (-6.2 eV). Compared with the TFB only devices, the external quantum efficiency (EQE) of devices with blended HTL improved from 15.9 % to 22.3 % without the increase of turn-on voltage for spin-coating fabricated device. Furthermore, the blended HTL prolonged the T90 and T70 lifetime from 5.4 h and 31.1 h to 39.4 h and 148.9 h, respectively. These enhancements in lifetime are attributed to the low hole-injection barrier at HTL/QD interface and high thermal stability of blended HTL after crosslinking. Moreover, the crosslinked blended HTL showed excellent solvent resistance after cross-linking and the EQE of the inkjet-printed red QLEDs reached 16.9 %.
关键词： charge balance,quantum dots light-emitting diodes,blended HTL,solvent resistance,inkjet printing
更新于2025-09-23 15:19:57
-
Separation and recovery of materials from the waste light emitting diode (LED) modules by solvent method
摘要： Nowadays, a large quantity of Light Emitting Diodes (LEDs) have been produced and updated with the development of optoelectronic industry. At the same time, many waste LEDs are discarded. However, there are many metals and non-metals in waste LEDs, which may cause secondary pollution and waste of resources if disposed improperly. In this study, solvent method was used to dissociate the waste LED modules and recycle resources. Firstly, the components of the waste LED modules were analyzed. The main component of the transparent plastic part, usually used as packaging materials, is cured epoxy resin, and the main component of the white plastic part as the skeleton of LED modules is a mixture of polyphenylene oxide (PPO) and polystyrene (PS). Then, eight organic solvents, [EMIM+]BF4? ion liquid and sodium hydroxide (NaOH) inorganic reagent were tried to separate a 40 × 40 mm2 waste LED module respectively. The results showed that only three organic solvents—dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl-sulfoxide (DMSO) could dissociate the waste LED module very well. The used DMF solution was purified by rotary evaporation, and the regenerative DMF solution could be reused because its property has not changed. The solid residue obtained after rotary evaporating DMF was identified as polystyrene (PS). It was inferred that the waste LED module was dissociated through the DMF dissolving the PS of white plastic. In addition, the effect of DMF, DMA and DMSO dissociating the waste LED modules with the change of temperature was discussed. It was found that the choice of suitable solvent is a key for this method, and the heating temperature was also a very important factor. Finally, it was measured that the cured epoxy resin and the white plastic of the waste LED module accounted for about 31.4% (w/w) and 37.7% (w/w) respectively, which can be recycled. In short, the method not only separated completely the waste LED module and its each part was recycled easily, but the solvents can be reused. This study suggests a new route to recycle LEDs due to its environmentally friendly process, which may exert a significantly beneficial impact on our environment.
关键词： Organic solvent,DMF,LED module
更新于2025-09-23 15:19:57
-
[Springer Theses] The Electronic Transitions of Molecular Oxygen || Solvent Effects on the O2(a1?g) → O2(b1$$\Sigma_{\text{g}}^{ + }$$) Transition
摘要： In this chapter, we have presented O2(a1Δg) → O2(b1Σ+g) absorption spectra and extinction coefficients for oxygen in 16 solvents. Through the Strickler-Berg equation, these data were converted into the corresponding O2(b1Σ+g) → O2(a1Δg) radiative rate constants to give the first comprehensive set of data on the probability of the O2(b1Σ+g) → O2(a1Δg) transition in solution. With these data in hand, energies and transition probabilities of all three electronic transitions in oxygen have been quantified in a wide range of solvents. We find that our data is consistent with the theoretical framework put forth by Minaev. Nevertheless, our data also suggest that the interaction between oxygen and the solvent takes place through different mechanisms that are simultaneously acting to perturb each of the electronic transitions in oxygen in different ways. In our mind, the system must now be subjected to more systematic and extensive theoretical investigations, in order to quantitatively rationalize these experimental observations.
关键词： Minaev’s theory,radiative rate constants,O2(a1Δg) → O2(b1Σ+g) transition,Strickler-Berg equation,solvent effects
更新于2025-09-23 15:19:57
-
Photocatalytic Dye and Cr(VI) Degradation Using a Metal-Free Polymeric g-C3N4 Synthesized from Solvent-Treated Urea
摘要： The development of visible-light-driven polymeric g-C3N4 is in response to an emerging demand for the photocatalytic dye degradation and reduction of hexavalent chromium ions. We report the synthesis of g-C3N4 from urea treated with various solvents such as methanol, ethanol, and ethylene glycol. The samples were characterized and the Williamson–Hall method was applied to investigate the lattice strain of the samples. The activity of the samples was evaluated by observing the degradation of methyl orange and K2Cr2O7 solution under light irradiation. Photocatalytic reaction kinetics were determined as pseudo-first-order and zero-order for the degradation of methyl orange and reduction of hexavalent chromium, respectively. Due to the inhibited charge separation resulting from the small lattice strain, reduced crystal imperfection, and sheet-like structure, g-C3N4 obtained from ethanol-treated urea exhibited the highest activity among the evaluated samples.
关键词： solvent-treated urea,Cr(VI) reduction,g-C3N4,photocatalytic degradation
更新于2025-09-19 17:15:36
-
First-principles investigation of the double ESIPT process in a thiophene-based dye
摘要： The unusual emission spectrum of 2,5-bis(benzoxazol-2-yl)thiophene-3,4-diol (BBTP) is investigated. The complexity of the emission spectrum of this dye is due to the presence of two excited-state intramolecular proton transfer (ESIPT) sites that give rise to three non-equivalent tautomers. The different maxima were experimentally attributed to the initial double enol form, the single ESIPT enol–keto tautomer, and the double ESIPT structure. Our simulations, based on Time Dependent Density Functional Theory (TD-DFT) and post Hartree–Fock methods [ADC(2) and CC2] coupled to different schemes to include the solvent polarisation response, are able to reproduce the key experimental outcomes. Moreover, we prove that for solving the inconsistencies present in earlier theoretical studies, a state-specific solvation approach is needed: one should go beyond the standard linear-response scheme in polarisable dielectric models. Finally, using a validated model, we explore the impact of substitution by donor and acceptor groups.
关键词： TD-DFT,emission spectrum,BBTP,CC2,tautomers,ADC(2),ESIPT,solvent models
更新于2025-09-19 17:15:36