Colloidal perovskite nanocrystals, or quantum dots (QDs), have quickly emerged and exhibited unique opportunities for optoelectronic applications. This is due to their excellent optical and ...photovoltaic properties as well as composition tunability. Currently, there are only a limited number of publications correlating QD synthesis optimization with relevant device performance. Here, CsPbI3 QDs have been successfully synthesized and displayed improved optoelectrical properties by implementing an in situ ytterbium (Yb) doping strategy during synthesis. Systematic investigations were carried out to examine the effects of Yb-doping. Preliminary experimental results indicated that Yb3+ lanthanide cations could effectively reduce the number of defects and trap states caused by surface and lattice vacancies. This result contributes to an improvement in QD photoluminescence quantum yield (PLQY), material crystallinity, thermal stability and carrier transport. Consequently, the solar cells adopting optimally Yb-doped CsPbI3 QDs achieved the best power conversion efficiency (PCE) of 13.12% and displayed significantly improved storage stability under ambient conditions. These results indicate that in situ doping has great potential to improve the quality of the resultant perovskite QDs. This approach can provide a new path to a breakthrough in QD based solar cell technology.
Surface manipulation of quantum dots (QDs) has been extensively reported to be crucial to their performance when applied into optoelectronic devices, especially for photovoltaic devices. In this ...work, an efficient surface passivation method for emerging CsPbI3 perovskite QDs using a variety of inorganic cesium salts (cesium acetate (CsAc), cesium idodide (CsI), cesium carbonate (Cs2CO3), and cesium nitrate (CsNO3)) is reported. The Cs‐salts post‐treatment can not only fill the vacancy at the CsPbI3 perovskite surface but also improve electron coupling between CsPbI3 QDs. As a result, the free carrier lifetime, diffusion length, and mobility of QD film are simultaneously improved, which are beneficial for fabricating high‐quality conductive QD films for efficient solar cell devices. After optimizing the post‐treatment process, the short‐circuit current density and fill factor are significantly enhanced, delivering an impressive efficiency of 14.10% for CsPbI3 QD solar cells. In addition, the Cs‐salt‐treated CsPbI3 QD devices exhibit improved stability against moisture due to the improved surface environment of these QDs. These findings will provide insight into the design of high‐performance and low‐trap‐states perovskite QD films with desirable optoelectronic properties.
This work reports an efficient post‐treatment method for CsPbI3 perovskite quantum dots (QDs) using cesium cations, which can passivate the CsPbI3 surface and improve the electron coupling of QDs. Finally, the best CsPbI3 QD solar cell with an impressive efficiency of 14.10% is achieved by cesium acetate (CsAc) and exhibits improved stability against moisture.
In this work, the way in which ambient moisture impacts the photovoltaic performance of conventional PCBM and emerging polymer acceptor–based organic solar cells is examined. The device performance ...of two representative p‐type polymers, PBDB‐T and PTzBI, blended with either PCBM or polymeric acceptor N2200, is systemically investigated. In both cases, all‐polymer photovoltaic devices processed from high‐humidity ambient conditions exhibit significantly enhanced moisture‐tolerance compared to their polymer–PCBM counterparts. The impact of moisture on the blend film morphology and electronic properties of the electron acceptor (N2200 vs PCBM), which results in different recombination kinetics and electron transporting properties, are further compared. The impact of more comprehensive ambient conditions (moisture, oxygen, and thermal stress) on the long‐term stability of the unencapsulated devices is also investigated. All‐polymer solar cells show stable performance for long periods of storage time under ambient conditions. The authors believe that these findings demonstrate that all‐polymer solar cells can achieve high device performance with ambient processing and show excellent long‐term stability against oxygen and moisture, which situate them in an advantageous position for practical large‐scale production of organic solar cells.
Herein, significantly improved ambient operational stability, including air processability and long‐term stability in polymer‐polymer solar cells relative to polymer‐PCBM devices is demonstrated. It is shown that all‐polymer blends exhibit excellent stability, with an efficiency approaching 9% despite being processed under high‐humidity conditions. Additionally, the all‐polymer cell shows improved stability under thermal stress and ambient conditions without encapsulation.
Aluminum (Al) toxicity is perceived as a potential threat to the integrity of forest ecosystems. The detrimental effects of acidic deposition on trees are caused by mobilization of Al in soils. To ...better understand how roots adapt to acidic deposition releasing toxic Al including the endogenous hormones {{abscisic acid (ABA), gibberellic acid (GA
3
), indole-3-acetic acid (IAA) and zeatin riboside (ZR)}}, chemistry {{Ca/Al ratio, and base saturation (BS)}}, and growth rate, with the 100-day-old Masson pine (
Pinus massoniana
Lamb.) seedlings as research target, we studied the responses of the hormones to rhizospheric Al concentrations and their relationships between pine growth rates and Ca/Al ratios in the simulated soil solutions and forested soils differing in BS. In a hydroponic culture, after the seedlings were exposed to the simulated soil solutions containing 0 (control), 50, 100, 150, 200 µM Al at pH 4.0, ABA formed in the roots increased significantly with the time and intensity of Al exposure. ABA concentrations were positively correlated with rhizospheric Al concentrations (r = 0.92), whereas the opposite trend was seen for GA
3
(r = −0.77). Simultaneously, IAA and ZR did not change with the increasing Al concentrations. Increasing of either Al concentration or exposure time caused an inhibition of root elongation and seedling growth. Moreover, in a field soil culture, the seedlings were grown for 60 days (d) in either A horizon soils with a BS above 17% or B horizon soils with a BS below 7%. Evident regional variation of ABA concentrations was observed in the pine roots, which declined in the order: Jin Yun Shan > Nan Shan > Tie Shan Ping, as well as B horizon soil > A horizon soil. Also, ABA concentrations were negatively correlated with soil Ca/Al ratios (r = −0.67). The opposite trends were simultaneously observed for GA
3
, IAA and ZR (r = 0.45, 0.25 and 0.18, respectively). Based on the laboratory and field results, under the influence of acid deposition, ABA, and GA
3
may play an important synergic role in regulating Al resistance of Masson pine as an Al-stress signal.
Graphic abstract
Prior to entering the water body, microplastics (MPs) are mostly collected at the sewage treatment plant and the biological treatment unit is the sewage treatment facility's central processing unit. ...This review aims to present a comprehensive analysis of the detrimental impacts of MPs on the biological treatment unit of a sewage treatment plant and it covers how MPs harm the effluent quality of biological treatment processes. The structure of microbial communities is altered by MPs presence and additive release, which reduces functional microbial activity. Extracellular polymers, oxidative stress, and enzyme activity are explored as micro views on the harmful mechanism of MPs on microorganisms, examining the toxicity of additives released by MPs and the harm caused to microorganisms by harmful compounds that have been adsorbed in the aqueous environment. This article offers a theoretical framework for a thorough understanding of the potential problems posed by MPs in sewage treatment plants and suggests countermeasures to mitigate those risks to the aquatic environment.
Current efforts on lead sulfide quantum dot (PbS QD) solar cells are mostly paid to the device architecture engineering and postsynthetic surface modification, while very rare work regarding the ...optimization of PbS synthesis is reported. Here, PbS QDs are successfully synthesized using PbO and PbAc2 · 3H2O as the lead sources. QD solar cells based on PbAc‐PbS have demonstrated a high power conversion efficiency (PCE) of 10.82% (and independently certificated values of 10.62%), which is significantly higher than the PCE of 9.39% for PbO‐PbS QD based ones. For the first time, systematic investigations are carried out on the effect of lead precursor engineering on the device performance. It is revealed that acetate can act as an efficient capping ligands together with oleic acid, providing better surface coverage and replace some of the harmful hydroxyl (OH) ligands during the synthesis. Then the acetate on the surface can be exchanged by iodide and lead to desired passivation. This work demonstrates that the precursor engineering has great potential in performance improvement. It is also pointed out that the initial synthesis is an often neglected but critical stage and has abundant room for optimization to further improve the quality of the resultant QDs, leading to breakthrough efficiency.
Light is shed on the effects of lead precursors on the performance of lead sulfide quantum dot (PbS QD) solar cells. The efficiency of PbS QDs synthesized from PbAc is significantly higher than that from PbO and the mechanism underneath is investigated. A new avenue is opened to improve the performance of PbS QD photovoltaic devices by lead precursor engineering.
Pinus massoniana Lamb. is one of the most sensitive species to acid deposition among forest woody plants, but differences in acid resistance among pine families still exist. It is of great ...significance to study the differences in acid resistance of Masson pine families and to analyze the physiological regulation mechanism of their acid resistance. In this study, the 100-day-old seedlings of 16 Masson pine families were treated with the simulated acid rain (SAR) at different pH levels (5.6, 4.5, 3.5 and 2.5) for 100 days to investigate the plant morphology, chlorophyll content, and root physiological responses. Results showed that pine family No. 35 maintained the good morphology, high chlorophyll content and organic acids secretion, and low plasma membrane permeability exposed to SAR, while family No. 79 presented the opposite. SAR not only increased the root plasma membrane permeability, but also induced an exudation of organic acids from the pine roots, and the test parameters changed sharply when the SAR pH was lower than 4.5. The results indicated that Masson pine could resist to acidic environment (pH 4.5-5.6), and family No. 35 had the acid resistance while the family No. 79 was sensitive to acid stress. The acid resistance diversity of different pine families had close relation with the root physiological processes, including the root plasma membrane permeability and organic acids secretion. For the future research, the natural genetic variation of Masson pine in response to acid stress and its acid resistance mechanism should be further studied.
Lead sulphide (PbS) nanocrystals (NCs) are promising materials for low-cost, high-performance optoelectronic devices. So far, PbS NCs have to be first synthesized with long-alkyl chain organic ...surface ligands and then be ligand-exchanged with shorter ligands (two-steps) to enable charge transport. However, the initial synthesis of insulated PbS NCs show no necessity and the ligand-exchange process is tedious and extravagant. Herein, we have developed a direct one-step, scalable synthetic method for iodide capped PbS (PbS-I) NC inks. The estimated cost for PbS-I NC inks is decreased to less than 6 $·g
, compared with 16 $·g
for conventional methods. Furthermore, based on these PbS-I NCs, photodetector devices show a high detectivity of 1.4 × 10
Jones and solar cells show an air-stable power conversion efficiency (PCE) up to 10%. This scalable and low-cost direct preparation of high-quality PbS-I NC inks may pave a path for the future commercialization of NC based optoelectronics.
Surface passivation is essential to realize high photovoltaic performance for solar cells based on PbS quantum dots (QDs). The recently developed solution-phase ligand-exchange strategy can greatly ...simplify the device fabrication process compared with the traditional layer by layer method. However, the surface hydroxyl ligand (OH) on the PbS QD surface, a main source of trap states, cannot be avoided in the solution-phase ligand-exchange process and has not been paid attention yet. Meanwhile, the unsatisfactory colloidal stability of current PbS QD ink is also a barrier for its industrial application and waiting for solutions. Here, we demonstrate a multiple-passivation strategy by solution-phase ligand engineering in lead halide exchanged QD ink. It was found that our facile approach can efficiently reduce the trap states of PbS QD ink by suppressing the amount of surface hydroxyl groups. Moreover, ligand engineering can also increase the interaction between QDs and solvent, which endows the QD ink with remarkably improved colloidal stability. As a result, a significant improvement of PCE from 9.99% to 11.18% and device stability were realized. Our results present a new passivation method for solution-phase ligand exchanged QD ink and the improved colloidal stability may help to boost the industrial application of PbS QD based solar cells.
A multiple-passivation strategy by solution-phase ligand engineering in lead halide exchanged QDs ink is presented, which result in remarkably improved colloidal stability of QDs ink and enhanced device performance.
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•Magnetic cellulose powders were derived from agricultural waste Juncus effusus fiber.•Magnetic cellulose powers were used for purification of dye-contaminated ethanol-water ...mixture.•99.9 % of adsorption efficiency should be corrected as Excellent adsorption efficiency.
Eco-friendly ethanol (EtOH)-water (H2O) mixture has demonstrated huge potential in the textile industry. However, the uncontrolled discharge of dye-contaminated EtOH-H2O mixture to the ecosystem has numerous adverse effects. Herein, a sustainable approach utilizing the agricultural waste biomass-Juncus effusus (JE) to synthesize magnetic cellulose JE powders (M-JEPs) has been proposed for purification of dye-contaminated EtOH-H2O mixture. Batch experiments and physical-chemical analyses were performed to explore the adsorption performance and mechanism. The as-prepared cellulose M-JEPs exhibited ultrafast adsorption performance, which can reach the adsorption equilibrium within 10 min. The adsorption isotherms and kinetics demonstrated that the adsorption fitted well with the Langmuir isotherm and pseudo-second-order kinetic models, exhibiting the maximum adsorption capacity towards C.I. Reactive Red 195 and C.I. Reactive Blue 222 of 58.21 mg/g and 86.06 mg/g at the temperature of 303K. These findings indicate the feasibility of using cellulose M-JEPs for rapid purification of the dye-contaminated EtOH-H2O mixture.
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