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
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
Although significant advancements have been achieved in the performance of organic solar cells(OSCs),the intrinsic stability of active layer materials and their morphological instability continue to impede their comme...Although significant advancements have been achieved in the performance of organic solar cells(OSCs),the intrinsic stability of active layer materials and their morphological instability continue to impede their commercial viability.Herein,a strategy of incorporating a hindered phenolic antioxidant AO1010 into polymer donors of pseudo-planar heterojunction(PPHJ)OSCs was put forward to successfully enhance photo-oxidative and morphological stability.AO1010 that features multiple hydroxyl binding sites makes it highly reactive with superoxide radicals,leading to the quenching of radicals and the termination of radical-induced chain degradation reactions,thereby enhancing the intrinsic stability of the material.Besides,due to the excellent thermal stability and significant steric hindrance of AO1010,it can prevent excessive aggregation of donor and acceptor materials,thus improving morphological stability.Moreover,the multiple hydroxyl groups in AO1010 can easily form hydrogen bonds with the fluorine atoms in the renowned donor PM6,enhancing intermolecular interactions.This leads to an increase in crystallinity of PM6,more orderly molecular packing,and improved gradient phase separation morphology,which benefits charge separation and transport.Consequently,compared with the PM6/BTP-eC9 control device,the optimized PPHJ device based on PM6+AO1010/BTP-eC9 achieved a significantly improved PCE of 18.67% with much better stability.Strikingly,AO1010 demonstrates universal applicability for morphology optimization and stability enhancement.When incorporated into the PM6/L8-BO system,it delivered an impressive efficiency of up to 19.03% with excellent stability.This work put forward an effective strategy to improve the morphology and photo-oxidation stability of active layer,paving the way for the accelerated commercialization of OSCs.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
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
Small-molecular organic solar cells usually exhibited unsatisfactory device stability,which might originate from their molecular diffusion behaviors.Herein,based on the all-small-molecule system HD-1:BTP-eC9,we report...Small-molecular organic solar cells usually exhibited unsatisfactory device stability,which might originate from their molecular diffusion behaviors.Herein,based on the all-small-molecule system HD-1:BTP-eC9,we reported a dimerized acceptor DC9,and its corresponding monomer acceptor eOD.In comparison with eOD,the dimeric acceptor DC9 displayed higher glass transition temperature(Tg)but reduced molecular planarity and crystallinity.The all-small molecule blend utilizing HD-1:eOD demonstrated a power conversion efficiency(PCE)of 15.13%,surpassing the value of 14.10%for the HD-1:DC9 blend.While,incorporating polymer donor PM6 into the HD-1:DC9 blend improved its morphology and charge transport dynamics,resulting in a device efficiency of over 16%,representing the rare case utilizing small-molecular donor and dimeric acceptor with PCE over 16%.Morphological characterization results affirmed that the surface morphologies and molecular packing behaviors of the blend films based on HD-1 were largely retained even after prolonged annealing and aging at 85℃.Consequently,the PCEs of the blend films based on HD-1:eOD,HD-1:DC9,and HD-1:PM6:DC9 consistently remained over 98%of their initial efficiency after 1000 h of thermal annealing aging at 85℃.These findings highlight the potential of small-molecular based active layer in the fabrication of efficient and stable OSCs.展开更多
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.
基金financially supported by the National Natural Science Foundation of China(NSFC)(22479066 and 52333006)Jiangxi Provincial Natural Science Foundation(20212ACB203005 and 20224ACB214002)+1 种基金the Thousand Talents Plan of Jiangxi Province(jxsq2019101051)the financial support from Research Grants Council(RGC)of Hong Kong(General Research Fund No.14303519).
文摘Although significant advancements have been achieved in the performance of organic solar cells(OSCs),the intrinsic stability of active layer materials and their morphological instability continue to impede their commercial viability.Herein,a strategy of incorporating a hindered phenolic antioxidant AO1010 into polymer donors of pseudo-planar heterojunction(PPHJ)OSCs was put forward to successfully enhance photo-oxidative and morphological stability.AO1010 that features multiple hydroxyl binding sites makes it highly reactive with superoxide radicals,leading to the quenching of radicals and the termination of radical-induced chain degradation reactions,thereby enhancing the intrinsic stability of the material.Besides,due to the excellent thermal stability and significant steric hindrance of AO1010,it can prevent excessive aggregation of donor and acceptor materials,thus improving morphological stability.Moreover,the multiple hydroxyl groups in AO1010 can easily form hydrogen bonds with the fluorine atoms in the renowned donor PM6,enhancing intermolecular interactions.This leads to an increase in crystallinity of PM6,more orderly molecular packing,and improved gradient phase separation morphology,which benefits charge separation and transport.Consequently,compared with the PM6/BTP-eC9 control device,the optimized PPHJ device based on PM6+AO1010/BTP-eC9 achieved a significantly improved PCE of 18.67% with much better stability.Strikingly,AO1010 demonstrates universal applicability for morphology optimization and stability enhancement.When incorporated into the PM6/L8-BO system,it delivered an impressive efficiency of up to 19.03% with excellent stability.This work put forward an effective strategy to improve the morphology and photo-oxidation stability of active layer,paving the way for the accelerated commercialization of OSCs.
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.
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financial support from MoST of China(2022YFB4200400,2019YFA0705900,and 2023YFE0210400)NSFC(52303237,21935007,52025033,52373189,and 22361132530).
文摘Small-molecular organic solar cells usually exhibited unsatisfactory device stability,which might originate from their molecular diffusion behaviors.Herein,based on the all-small-molecule system HD-1:BTP-eC9,we reported a dimerized acceptor DC9,and its corresponding monomer acceptor eOD.In comparison with eOD,the dimeric acceptor DC9 displayed higher glass transition temperature(Tg)but reduced molecular planarity and crystallinity.The all-small molecule blend utilizing HD-1:eOD demonstrated a power conversion efficiency(PCE)of 15.13%,surpassing the value of 14.10%for the HD-1:DC9 blend.While,incorporating polymer donor PM6 into the HD-1:DC9 blend improved its morphology and charge transport dynamics,resulting in a device efficiency of over 16%,representing the rare case utilizing small-molecular donor and dimeric acceptor with PCE over 16%.Morphological characterization results affirmed that the surface morphologies and molecular packing behaviors of the blend films based on HD-1 were largely retained even after prolonged annealing and aging at 85℃.Consequently,the PCEs of the blend films based on HD-1:eOD,HD-1:DC9,and HD-1:PM6:DC9 consistently remained over 98%of their initial efficiency after 1000 h of thermal annealing aging at 85℃.These findings highlight the potential of small-molecular based active layer in the fabrication of efficient and stable OSCs.
