The fast developing perovskite solar cells shows high efficiency and low cost.However,the stability problem restricts perovskite from commercial use.In this work,we have studied the effect of grain orientation on the ...The fast developing perovskite solar cells shows high efficiency and low cost.However,the stability problem restricts perovskite from commercial use.In this work,we have studied the effect of grain orientation on the morphological stability of perovskite thin films.By tuning the inorganic/organic ratio in the precursor solution,perovskite thin films with both high crystallinity and good morphological stability have been fabricated.The thermal stability of perovskite solar cells based on the optimized films has been tested.The device performance shows no degradation after annealing at 100℃ for 5h in air.This finding provides general guidelines for the development of thermally stable perovskite solar cells.展开更多
Tip splitting instability of cellular interface morphology in directional solidification is analyzed based on the bias field method proposed recently by Glicksman. The physical mechanism of tip instability is explaine...Tip splitting instability of cellular interface morphology in directional solidification is analyzed based on the bias field method proposed recently by Glicksman. The physical mechanism of tip instability is explained by analyzing the interface potential, the tangential energy flux, and the normal energy flux. A rigorous criterion for tip-splitting instability is established analytically, i.e., the ratio of the cellular tip radius to the cellular width α 〉3/2/π≈ 0.3899, which is in good agreement with simulation results. This study also reveals that the cellular tip splitting instability is attributable to weak Gibbs–Thomson energy acting on the interface.展开更多
This study investigated the conversion of monohydrocalcite (MHC) to anhydrous calcium carbonate. The primary material, MHC, was produced from waste brines containing Ca and Mg ions, reacted with sodium carbonate, whic...This study investigated the conversion of monohydrocalcite (MHC) to anhydrous calcium carbonate. The primary material, MHC, was produced from waste brines containing Ca and Mg ions, reacted with sodium carbonate, which may serve in the carbon capture and mineralisation approach. Two different approaches to the conversion were studied: 1) the conversion of MHC conversion to anhydrous calcium carbonates in air (under ambient conditions);2) the identification of conversion conditions which could be adapted for potential industrial application. The former focused on the effects of the synthesis system conditions of the primary material on the aragonite conversion process and the resulting aragonite morphology, whereas the latter covered the factors that accelerate conversion and influence the resulting morphology. The paper also discusses instances where MHC converts to the more stable polymorph, calcite. It was found that conditions leading to the polymorphic and morphological selection of converted minerals were temperature and humidity dependant.展开更多
Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular...Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular emitter with a flexible side chain always presents easily aggregation upon external treatment, and caused π-electronic coupling, which is undesirable for the efficiency and stability of deep-blue OLEDs. Herein, we proposed a side-chain coupling strategy to enhance the film morphological an emission stability of solution-processable small molecular deep-blue emitter. In contrary to “parent” MC8 TPA,the crosslinkable styryl and vinyl units were introduced as ended unit at the side-chain of Cm TPA and OEYTPA. Interestingly, Cm TPA and OEYTPA films present a relatively stable morphology and uniform deep-blue emission after thermal annealing(160 ℃) in the atmosphere, different to the discontinuous MC8 TPA annealed film. Besides, compared to the Cm TPA and OEYTPA ones, serious polaron formation in the MC8 TPA annealed film also negative to the deep-blue emission, according to transient absorption analysis. Therefore, both Cm TPA and OEYTPA annealed film obtained at 140 ℃ present an excellent deep-blue ASE behavior with a 445 nm, but absence for MC8 TPA ones, associated with the disruption of annealed films. Finally, enhancement of device performance based on Cm TPA and OEYTPA film(~40%)after thermal annealing with a similar performance curves also confirmed the assumption above. Therefore, these results also supported the effectiveness of our side-chain coupling strategy for optoelectronic applications.展开更多
In the design of conjugated molecules,modular production enables materials to easily realize structure modification and precisely tune their photoelectrical property.Construction of a novel and universal building bloc...In the design of conjugated molecules,modular production enables materials to easily realize structure modification and precisely tune their photoelectrical property.Construction of a novel and universal building block is crucial to design and manufacture high performance and stable conjugated molecules for optoelectronic application.Herein,we originally demonstrated a universal 4-qualifiable fluorene-based building block,which is a fundamental molecular segment to functionalize and obtain novel conjugated materials.Compared to the traditional modification at 9-site,additional 4-position functionalization provided an exciting blueprint to not only tune electronic structure and excited state via p-n molecular design engineering and space charge-transfer strategy,but also allow for optimizing intermolecular arrangement and obtaining solution-processing ability.The introduction of the 4-site substituent in fluorene based semiconductors may endow materials with unique properties.Finally,we successfully prepared two stable deep-blue light-emitting conjugated polymer,PODOPF and PODOF,by utilizing the 4-substituent fluorene based building block.It is believable that the performance,stability and processibility of reported outstanding fluorene-based conjugated molecules can be further optimized based on this universal building block.展开更多
基金Proiect supported by the Youth Innovation Promotion Association of CAS(No.2015167)
文摘The fast developing perovskite solar cells shows high efficiency and low cost.However,the stability problem restricts perovskite from commercial use.In this work,we have studied the effect of grain orientation on the morphological stability of perovskite thin films.By tuning the inorganic/organic ratio in the precursor solution,perovskite thin films with both high crystallinity and good morphological stability have been fabricated.The thermal stability of perovskite solar cells based on the optimized films has been tested.The device performance shows no degradation after annealing at 100℃ for 5h in air.This finding provides general guidelines for the development of thermally stable perovskite solar cells.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB610401)the National Natural Science Foundation of China(Grant No.51371151)the Free Research Fund of State Key Laboratory of Solidification Processing,China(Grant No.100-QP-2014)
文摘Tip splitting instability of cellular interface morphology in directional solidification is analyzed based on the bias field method proposed recently by Glicksman. The physical mechanism of tip instability is explained by analyzing the interface potential, the tangential energy flux, and the normal energy flux. A rigorous criterion for tip-splitting instability is established analytically, i.e., the ratio of the cellular tip radius to the cellular width α 〉3/2/π≈ 0.3899, which is in good agreement with simulation results. This study also reveals that the cellular tip splitting instability is attributable to weak Gibbs–Thomson energy acting on the interface.
文摘This study investigated the conversion of monohydrocalcite (MHC) to anhydrous calcium carbonate. The primary material, MHC, was produced from waste brines containing Ca and Mg ions, reacted with sodium carbonate, which may serve in the carbon capture and mineralisation approach. Two different approaches to the conversion were studied: 1) the conversion of MHC conversion to anhydrous calcium carbonates in air (under ambient conditions);2) the identification of conversion conditions which could be adapted for potential industrial application. The former focused on the effects of the synthesis system conditions of the primary material on the aragonite conversion process and the resulting aragonite morphology, whereas the latter covered the factors that accelerate conversion and influence the resulting morphology. The paper also discusses instances where MHC converts to the more stable polymorph, calcite. It was found that conditions leading to the polymorphic and morphological selection of converted minerals were temperature and humidity dependant.
基金supported by the National Natural Science Foundation of China (Nos.22075136,61874053)National Key Research and Development Program of China (No.2020YFA0709900)+5 种基金Natural Science Funds of the Education Committee of Jiangsu Province (No.18KJA430009)Natural Science Foundation of Jiangsu Province (No.BK20200700)“High-Level Talents in Six Industries” of Jiangsu Province (No.XYDXX-019)Chain Postdoctoral Science Foundation (No.2021M692623)the open research fund from State Key Laboratory of Supramolecular Structure and Materials (No.sklssm202108)Anhui Province Key Laboratory of Environmentfriendly Polymer Materials and Anhui Province Key Laboratory of Optoelectronic Materials Science and Technology。
文摘Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular emitter with a flexible side chain always presents easily aggregation upon external treatment, and caused π-electronic coupling, which is undesirable for the efficiency and stability of deep-blue OLEDs. Herein, we proposed a side-chain coupling strategy to enhance the film morphological an emission stability of solution-processable small molecular deep-blue emitter. In contrary to “parent” MC8 TPA,the crosslinkable styryl and vinyl units were introduced as ended unit at the side-chain of Cm TPA and OEYTPA. Interestingly, Cm TPA and OEYTPA films present a relatively stable morphology and uniform deep-blue emission after thermal annealing(160 ℃) in the atmosphere, different to the discontinuous MC8 TPA annealed film. Besides, compared to the Cm TPA and OEYTPA ones, serious polaron formation in the MC8 TPA annealed film also negative to the deep-blue emission, according to transient absorption analysis. Therefore, both Cm TPA and OEYTPA annealed film obtained at 140 ℃ present an excellent deep-blue ASE behavior with a 445 nm, but absence for MC8 TPA ones, associated with the disruption of annealed films. Finally, enhancement of device performance based on Cm TPA and OEYTPA film(~40%)after thermal annealing with a similar performance curves also confirmed the assumption above. Therefore, these results also supported the effectiveness of our side-chain coupling strategy for optoelectronic applications.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20200700)National Natural Science Foundation of China(Nos.22075136,61874053)+4 种基金Natural Science Funds of the Education Committee of Jiangsu Province(No.18KJA430009)"High-Level Talents in Six Industries"of Jiangsu Province(No.XYDXX-019)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Nos.KYCX21_1097,KYCX21_0771)Nanjing Vocational University of Industry Technology Start-up Fund(No.YK21-02-07)the open research fund from Anhui Province Key Laboratory of Environment-friendly Polymer Materials and Anhui Province Key Laboratory of Optoelectronic Materials Science and Technology.
文摘In the design of conjugated molecules,modular production enables materials to easily realize structure modification and precisely tune their photoelectrical property.Construction of a novel and universal building block is crucial to design and manufacture high performance and stable conjugated molecules for optoelectronic application.Herein,we originally demonstrated a universal 4-qualifiable fluorene-based building block,which is a fundamental molecular segment to functionalize and obtain novel conjugated materials.Compared to the traditional modification at 9-site,additional 4-position functionalization provided an exciting blueprint to not only tune electronic structure and excited state via p-n molecular design engineering and space charge-transfer strategy,but also allow for optimizing intermolecular arrangement and obtaining solution-processing ability.The introduction of the 4-site substituent in fluorene based semiconductors may endow materials with unique properties.Finally,we successfully prepared two stable deep-blue light-emitting conjugated polymer,PODOPF and PODOF,by utilizing the 4-substituent fluorene based building block.It is believable that the performance,stability and processibility of reported outstanding fluorene-based conjugated molecules can be further optimized based on this universal building block.
