Perovskite quantum dots(PeQDs)endowed with capping ligands exhibit impressive optoelectronic properties and enable for costefficient solution processing and exciting application opportunities.We synthesize and charact...Perovskite quantum dots(PeQDs)endowed with capping ligands exhibit impressive optoelectronic properties and enable for costefficient solution processing and exciting application opportunities.We synthesize and characterize three different PeQDs with the same cubic CsPbBr_(3)core,but which are distinguished by the ligand composition and density.PeQD-1 features a binary didodecyldimethylammonium bromide(DDAB)and octanoic acid capping ligand system,with a high surface density of 1.53 nm^(-2),whereas PeQD-2 and PeQD-3 are coated by solely DDAB at a gradually lower surface density.We show that PeQD-1 endowed with highest ligand density features the highest dispersibility in toluene of 150 g/L,the highest photoluminescence quantum yield of 95%in dilute solution and 59%in a neat film,and the largest core-to-core spacing in neat thin films.We further establish that ions are released from the core of PeQD-1 when it is exposed to an electric field,although it comprises a dense coating of one capping ligand per four surface core atoms.We finally exploit these combined findings to the development of a light-emitting electrochemical cell(LEC),where the active layer is composed solely of solution-processed pure PeQDs,without additional electrolytes.In this device,the ion release is utilized as an advantage for the electrochemical doping process and efficient emissive operation of the LEC.展开更多
Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-sy...Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-synthesize conjugated polymer.Here,we address this issue through the pioneering employment of metal-free and facile-to-synthesize carbon nanodots(CNDs)as the emitter in functional LEC devices.Circular-shaped(average diameter=4.4 nm)and hydrophilic CNDs,which exhibit narrow cyan photoluminescence(peak=485 nm,full width at half maximum=30 nm)with a high quantum yield of 77%in dilute ethanol solution,were synthesized with a catalyst-free,one-step solvothermal process using low-cost and benign phloroglucinol as the sole starting material.The propensity of the planar CNDs to form emission-quenching aggregates in the solid state was inhibited by the inclusion of a compatible 2,7-bis(diphenylphosphoryl)-9,9’-spirobifluorene host compound,and we demonstrate that such pristine host-vip CND-LECs turn on to a peak luminance of 118 cd·m^(−2)within 5 s during constant current-density driving at 77 mA·cm^(−2).展开更多
We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bila...We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bilayer structure.The line-art emission is achieved through subtractive patterning of the electrolyte layer with a stylus,and the single-step patterning can be either manual for personalization and uniqueness or automated for high throughput and repeatability.We demonstrate that the light emission is effectuated by cation-assisted electron injection in the patterned regions and that the resulting emissive lines can be as narrow as a few micrometers.The versatility of the method is demonstrated through the attainment of a wide range of light-emission patterns and colors using a variety of different materials.Wepropose that this low-voltage-driven and easy-to-modify luminescent line-art technology could be of interest for emerging applications,such as active packaging and personalized gadgets.展开更多
基金The authors acknowledge generous support from J.C.Kempes Minnes Stipendiefond(No.SMK-1849.1,21-0015)the Swedish Energy Agency(Nos.45419-1,46523-1,and 50779-1)+4 种基金the Swedish Research Council(Nos.2018-03937,2019-02345,and 2020-04437)the Swedish Foundation for Strategic Research,Stiftelsen Olle Engkvist Byggmästare(Nos.186-0637 and 193-0578)Bertil&Britt Svenssons stiftelse för belysningsteknik,the Swedish Foundation for International Cooperation in Research,Higher Education via an Initiation Grant for Internationalization(No.2019-8553)Innovation Technology Platform Project Jointly Built by Yangzhou City and Yangzhou University,China(No.YZ2020268)Jiangsu Students’Innovation and Entrepreneurship Training Program(No.202211117040Z).
文摘Perovskite quantum dots(PeQDs)endowed with capping ligands exhibit impressive optoelectronic properties and enable for costefficient solution processing and exciting application opportunities.We synthesize and characterize three different PeQDs with the same cubic CsPbBr_(3)core,but which are distinguished by the ligand composition and density.PeQD-1 features a binary didodecyldimethylammonium bromide(DDAB)and octanoic acid capping ligand system,with a high surface density of 1.53 nm^(-2),whereas PeQD-2 and PeQD-3 are coated by solely DDAB at a gradually lower surface density.We show that PeQD-1 endowed with highest ligand density features the highest dispersibility in toluene of 150 g/L,the highest photoluminescence quantum yield of 95%in dilute solution and 59%in a neat film,and the largest core-to-core spacing in neat thin films.We further establish that ions are released from the core of PeQD-1 when it is exposed to an electric field,although it comprises a dense coating of one capping ligand per four surface core atoms.We finally exploit these combined findings to the development of a light-emitting electrochemical cell(LEC),where the active layer is composed solely of solution-processed pure PeQDs,without additional electrolytes.In this device,the ion release is utilized as an advantage for the electrochemical doping process and efficient emissive operation of the LEC.
基金support from J.C.Kempes Minnes Stipendiefond(No.SMK-1849.1)the Swedish Energy Agency(Nos.45419-1,46523-1,and 50779-1)+2 种基金the Swedish Research Council(Nos.2017-04380,2017-04862,2018-03937,and 2019-02345)the Swedish Foundation for Strategic Research,Stiftelsen Olle Engkvist Byggmästare(Nos.186-0637 and 193-0578)Bertil&Britt Svenssons stiftelse för belysningsteknik,the Swedish Foundation for International Cooperation in Research and Higher Education via an Initiation Grant for Internationalization(No.2019-8553)。
文摘Light-emitting electrochemical cells(LECs)can be fabricated with cost-efficient printing and coating methods,but a current drawback is that the LEC emitter is commonly either a rare-metal complex or an expensive-to-synthesize conjugated polymer.Here,we address this issue through the pioneering employment of metal-free and facile-to-synthesize carbon nanodots(CNDs)as the emitter in functional LEC devices.Circular-shaped(average diameter=4.4 nm)and hydrophilic CNDs,which exhibit narrow cyan photoluminescence(peak=485 nm,full width at half maximum=30 nm)with a high quantum yield of 77%in dilute ethanol solution,were synthesized with a catalyst-free,one-step solvothermal process using low-cost and benign phloroglucinol as the sole starting material.The propensity of the planar CNDs to form emission-quenching aggregates in the solid state was inhibited by the inclusion of a compatible 2,7-bis(diphenylphosphoryl)-9,9’-spirobifluorene host compound,and we demonstrate that such pristine host-vip CND-LECs turn on to a peak luminance of 118 cd·m^(−2)within 5 s during constant current-density driving at 77 mA·cm^(−2).
基金support from the Swedish Foundation for Strategic Researchthe Swedish Research Council+3 种基金the Swedish Energy Agencythe Kempe Foundationthe Knut and Alice Wallenberg FoundationsAforsk.
文摘We present a direct-write patterning method for the realization of electroluminescent(EL)line art using a surface-emissive light-emitting electrochemical cell with its electrolyte and EL material separated into a bilayer structure.The line-art emission is achieved through subtractive patterning of the electrolyte layer with a stylus,and the single-step patterning can be either manual for personalization and uniqueness or automated for high throughput and repeatability.We demonstrate that the light emission is effectuated by cation-assisted electron injection in the patterned regions and that the resulting emissive lines can be as narrow as a few micrometers.The versatility of the method is demonstrated through the attainment of a wide range of light-emission patterns and colors using a variety of different materials.Wepropose that this low-voltage-driven and easy-to-modify luminescent line-art technology could be of interest for emerging applications,such as active packaging and personalized gadgets.
