The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the intera...The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the interaction between two perpendicular π-systems of various oligothiophene substituted spirofluorenes is conducted. The results demonstrate that the interaction be- tween two perpendicular branches is reduced by oligothiophene substitutions. Photoexcitation induced relaxation is mainly located on one of the equivalent branches or the branch with longer conjugation length. In addition to these benefits brought by 9,9-spirobifluorene center, the specific oligothiophene moieties linked to the spirt center also have properties of significant merit, such as the ability to tune energy levels and emission colors by controlling the conjugation length.展开更多
The simultaneous achievement of chiral multiple-resonance thermally activated delayed fluorescence(MR-TADF)emitters with narrowband and circularly polarized electroluminescence(CPEL)poses a challenge.Herein,a MR-TADF ...The simultaneous achievement of chiral multiple-resonance thermally activated delayed fluorescence(MR-TADF)emitters with narrowband and circularly polarized electroluminescence(CPEL)poses a challenge.Herein,a MR-TADF emitter,Spiro-BNCz,embedding spirofluorene structure was developed and chiral separated,whose emission peaks at 528 nm in toluene with Commission Internationale de L’Eclairage coordinates of(0.26,0.69).The conjugation extension caused by embedding sulfur substituted spirofluorene on B/N framework shortens the singlettriplet energy gap and increases spin-orbital coupling matrix element.Therefore,a fast reverse intersystem crossing rate constant of 2.8×10^(6)s^(−1)and a high photoluminescence efficiency of 92%in film were achieved.The organic light-emitting diode(OLED)exhibits a maximum external quantum efficiency of 32.3%.Particularly,the circularly polarized OLEDs based on Spiro-BNCz enantiomers show symmetric CPEL with dissymmetry factors(|gEL|)≈10^(−3).展开更多
CONSPECTUS:Organic hole-transporting materials(HTMs)are of importance in the progress of new-generation photovoltaics,notably in perovskite solar cells(PSCs),solid-state dye-sensitized solar cells(sDSCs),and organic s...CONSPECTUS:Organic hole-transporting materials(HTMs)are of importance in the progress of new-generation photovoltaics,notably in perovskite solar cells(PSCs),solid-state dye-sensitized solar cells(sDSCs),and organic solar cells(OSCs).These materials play a vital role in hole collection and transportation,significantly impacting the power conversion efficiency(PCE)and overall stability of photovoltaic devices.The emergence of spiro(fluorene-9,9′-xanthene)(SFX)as a novel building block for organic HTMs has gained considerable attention in the field of photovoltaics.Its facile one-pot synthetic approach,straightforward purification,and physiochemical properties over the prototype HTM spiro-OMeTAD have positioned SFX as a highly attractive alternative.In this Account,we present a comprehensive and in-depth summary of our research work,focusing on the advancements in SFX-based organic HTMs in photovoltaic devices with a particular emphasis on PSCs and sDSCs.Several key objectives of our research have been focused on exploring strategies to improve the properties of SFX-based HTMs.(i)One of the critical aspects we have addressed is the improvement of film quality.By carefully designing the molecular structure and employing suitable synthetic approaches,we have achieved HTMs with excellent film-forming ability,resulting in uniform and smooth films over large areas.This achievement is pivotal in ensuring the reproducibility and efficiency of photovoltaic devices.Furthermore,(ii)our investigations have led to an improvement in hole mobility within the HTMs.Through molecular engineering,such as increasing the molecular conjugation and introducing multiple SFX units,we have demonstrated enhanced charge-carrier mobility.This advancement plays a crucial role in minimizing charge recombination losses and improving the overall device efficiency.Additionally,(iii)we have explored the concept of defect passivation in SFX-based HTMs.By incorporating Lewis base structures,such as pyridine groups,we have successfully coordinated to Pb2+in the perovskite layer,resulting in a passivation of surface defects.This defect passivation contributes to better stability and enhanced device performance.Throughout our review,we highlighted the potential and opportunities achieved through these steps.The combination of enhanced film quality,improved hole mobility,and defect passivation resulted in remarkable photovoltaic performance.Our findings have demonstrated promising short-circuit current densities,open-circuit voltages,fill factors,and PCEs,with some HTMs even outperforming the widely used spiro-OMeTAD.We believe that this review will not only provide a better understanding of SFX-based HTMs but also open new avenues for enhancing the performance of organic HTMs in photovoltaic and other organic electronic devices.By providing unique perspectives and exploring different strategies,we aim to inspire ongoing advancements in photovoltaic technologies and organic electronics.Meanwhile,the success of SFX-based HTMs in improving photovoltaic device performance holds great promise for the continued development of efficient and stable photovoltaic devices in the years to come.展开更多
Green organic semiconductors （GOS） have the four-element features, including biomass as stuffs, synthesis with the pot, atom and step economic （PASE） route, eco-friendly fabrication processes in aqueous phase, and...Green organic semiconductors （GOS） have the four-element features, including biomass as stuffs, synthesis with the pot, atom and step economic （PASE） route, eco-friendly fabrication processes in aqueous phase, and recy- clable devices, capturing the trend of organic electronics in the future. Herein, we reviewed the efforts that have been made on GOS by our group. We first made a brief introduction of organic （opto）electronics, followed by the design strategies of GOSs based on spirofluorenes. Concretely, we described the discovery of one-pot protocol to spirofluorenres and a pot-atom-step economic （PASE） platform of spiro[fluorene-9,9＇-xanthene] （SFX） for the mo- lecular design of organic semiconductors, as well as a state-of-the-art nanocrystalline films with eco-friendly pro- cedures. Then, we highlighted the progress on SFX-based organic semiconductors in the organic light-emitting di- ode （OLED） field. Finally, we conducted a summary on SFXs in OLED and an outlook on green semiconductors starting from biomass, via one-pot to spirofluorenes, to water-phase devices.展开更多
As a novel class of spirofluorenes,spirobifluorene(SBF)and spiro[fluo-rene-9,9'-xanthene]derivatives(SFXs)have orthogonal geometric config-uration,spiro-conjugation effect,and rigid steric hindrance,which can be w...As a novel class of spirofluorenes,spirobifluorene(SBF)and spiro[fluo-rene-9,9'-xanthene]derivatives(SFXs)have orthogonal geometric config-uration,spiro-conjugation effect,and rigid steric hindrance,which can be widely used in the fields of synthetic chemistry,materials chemistry and supramolecular chemistry.Due to their facile one-pot synthetic route,and to the variety of molecular designs,SFXs are expected to become new spiro functional materials that replace SBF.In this review,we present the history,development and expansion of SFXs synthesis in one-pot methods,and the advantages and limitations of one-pot synthesis are also dis-cussed.展开更多
Traditional photosensitizers are predominantly based on various types of polypyrrole macrocycles, which are generally used in homogeneous and/or suspension states. In the present study, a new non-polypyrrole-based pho...Traditional photosensitizers are predominantly based on various types of polypyrrole macrocycles, which are generally used in homogeneous and/or suspension states. In the present study, a new non-polypyrrole-based photosensitizer(LW-PBI) was developed via the introduction of a nonplanar spirofluorene into a derivative of perylene bisimides(PBI) containing two longalkyl chains. Photophysical studies demonstrated that the compound shows good solubility in common organic solvents, great photochemical stability, and high absorption efficiency in the visible light region. Due to containing of two energetically matchable, independent fluorescent units, the compound as prepared displays strong tendency to form non-fluorescent chargeseparated states under light irradiation in polar solvents. Based on the merits, LW-PBI was examined for its catalytic property in the photo-production of singlet oxygen in film state. Luckily, the compound is an effective photosensitizer in the generation of the active oxygen species as verified by its unique reaction with uric acid(UA). Further studies revealed that the effective photoproduction of singlet oxygen can be also realized via the utilization of a tiny and low-price LED lamp as a light source and as a film support. Detailed studies on the application of the conceptual device as a medical instrument for photodynamic therapy(PDT) are in progress.展开更多
基金financially supported by the National Basic Research Program of China (Grant No. 2009CB930601)the National Natural Science Foundation of China (Grant Nos. 20804020, 60976019, 50903028 and 20974046)+2 种基金the Program for New Century Excellent Talents in University (Grant No. NCET-07-0446)the Scientific and Technological Innovation Teams of Colleges and Universities in Jiangsu Province (Grant No. TJ207035)the Scientific Research Foundation of Nanjing University of Posts and Telecommunications (Grant No. NY210017)
文摘The electronic structures and optical properties of oligothiophene substituted spirofluorenes are investigated theoretically with semi-empirical quantum chemical calculations. A theoretical investigation of the interaction between two perpendicular π-systems of various oligothiophene substituted spirofluorenes is conducted. The results demonstrate that the interaction be- tween two perpendicular branches is reduced by oligothiophene substitutions. Photoexcitation induced relaxation is mainly located on one of the equivalent branches or the branch with longer conjugation length. In addition to these benefits brought by 9,9-spirobifluorene center, the specific oligothiophene moieties linked to the spirt center also have properties of significant merit, such as the ability to tune energy levels and emission colors by controlling the conjugation length.
基金National Natural Science Foundation of China,Grant/Award Numbers:92256304,21975119,22171092。
文摘The simultaneous achievement of chiral multiple-resonance thermally activated delayed fluorescence(MR-TADF)emitters with narrowband and circularly polarized electroluminescence(CPEL)poses a challenge.Herein,a MR-TADF emitter,Spiro-BNCz,embedding spirofluorene structure was developed and chiral separated,whose emission peaks at 528 nm in toluene with Commission Internationale de L’Eclairage coordinates of(0.26,0.69).The conjugation extension caused by embedding sulfur substituted spirofluorene on B/N framework shortens the singlettriplet energy gap and increases spin-orbital coupling matrix element.Therefore,a fast reverse intersystem crossing rate constant of 2.8×10^(6)s^(−1)and a high photoluminescence efficiency of 92%in film were achieved.The organic light-emitting diode(OLED)exhibits a maximum external quantum efficiency of 32.3%.Particularly,the circularly polarized OLEDs based on Spiro-BNCz enantiomers show symmetric CPEL with dissymmetry factors(|gEL|)≈10^(−3).
基金supported by the National Natural Science Foundation of China(Grant No.22279059)the Fundamental Research Funds for the Central Universities(No.30921011106,30923011030)the start-up funding from the NJUST.
文摘CONSPECTUS:Organic hole-transporting materials(HTMs)are of importance in the progress of new-generation photovoltaics,notably in perovskite solar cells(PSCs),solid-state dye-sensitized solar cells(sDSCs),and organic solar cells(OSCs).These materials play a vital role in hole collection and transportation,significantly impacting the power conversion efficiency(PCE)and overall stability of photovoltaic devices.The emergence of spiro(fluorene-9,9′-xanthene)(SFX)as a novel building block for organic HTMs has gained considerable attention in the field of photovoltaics.Its facile one-pot synthetic approach,straightforward purification,and physiochemical properties over the prototype HTM spiro-OMeTAD have positioned SFX as a highly attractive alternative.In this Account,we present a comprehensive and in-depth summary of our research work,focusing on the advancements in SFX-based organic HTMs in photovoltaic devices with a particular emphasis on PSCs and sDSCs.Several key objectives of our research have been focused on exploring strategies to improve the properties of SFX-based HTMs.(i)One of the critical aspects we have addressed is the improvement of film quality.By carefully designing the molecular structure and employing suitable synthetic approaches,we have achieved HTMs with excellent film-forming ability,resulting in uniform and smooth films over large areas.This achievement is pivotal in ensuring the reproducibility and efficiency of photovoltaic devices.Furthermore,(ii)our investigations have led to an improvement in hole mobility within the HTMs.Through molecular engineering,such as increasing the molecular conjugation and introducing multiple SFX units,we have demonstrated enhanced charge-carrier mobility.This advancement plays a crucial role in minimizing charge recombination losses and improving the overall device efficiency.Additionally,(iii)we have explored the concept of defect passivation in SFX-based HTMs.By incorporating Lewis base structures,such as pyridine groups,we have successfully coordinated to Pb2+in the perovskite layer,resulting in a passivation of surface defects.This defect passivation contributes to better stability and enhanced device performance.Throughout our review,we highlighted the potential and opportunities achieved through these steps.The combination of enhanced film quality,improved hole mobility,and defect passivation resulted in remarkable photovoltaic performance.Our findings have demonstrated promising short-circuit current densities,open-circuit voltages,fill factors,and PCEs,with some HTMs even outperforming the widely used spiro-OMeTAD.We believe that this review will not only provide a better understanding of SFX-based HTMs but also open new avenues for enhancing the performance of organic HTMs in photovoltaic and other organic electronic devices.By providing unique perspectives and exploring different strategies,we aim to inspire ongoing advancements in photovoltaic technologies and organic electronics.Meanwhile,the success of SFX-based HTMs in improving photovoltaic device performance holds great promise for the continued development of efficient and stable photovoltaic devices in the years to come.
文摘Green organic semiconductors （GOS） have the four-element features, including biomass as stuffs, synthesis with the pot, atom and step economic （PASE） route, eco-friendly fabrication processes in aqueous phase, and recy- clable devices, capturing the trend of organic electronics in the future. Herein, we reviewed the efforts that have been made on GOS by our group. We first made a brief introduction of organic （opto）electronics, followed by the design strategies of GOSs based on spirofluorenes. Concretely, we described the discovery of one-pot protocol to spirofluorenres and a pot-atom-step economic （PASE） platform of spiro[fluorene-9,9＇-xanthene] （SFX） for the mo- lecular design of organic semiconductors, as well as a state-of-the-art nanocrystalline films with eco-friendly pro- cedures. Then, we highlighted the progress on SFX-based organic semiconductors in the organic light-emitting di- ode （OLED） field. Finally, we conducted a summary on SFXs in OLED and an outlook on green semiconductors starting from biomass, via one-pot to spirofluorenes, to water-phase devices.
基金the National Natural Science Foundation of China(21774061,2207112 and 61935017)Natural Science Foundation major research program integration project(Grant Number 91833306)+1 种基金Six Peak Talents Foundation of Jiangsu Province(XCLCXTD-009)Open Project from State Key Labor-atory of Supramolecular Structure and Materials at Jilin University(No.sklssm202014).
文摘As a novel class of spirofluorenes,spirobifluorene(SBF)and spiro[fluo-rene-9,9'-xanthene]derivatives(SFXs)have orthogonal geometric config-uration,spiro-conjugation effect,and rigid steric hindrance,which can be widely used in the fields of synthetic chemistry,materials chemistry and supramolecular chemistry.Due to their facile one-pot synthetic route,and to the variety of molecular designs,SFXs are expected to become new spiro functional materials that replace SBF.In this review,we present the history,development and expansion of SFXs synthesis in one-pot methods,and the advantages and limitations of one-pot synthesis are also dis-cussed.
基金the National Natural Science Foundation of China(21527802,2167313,21820102005)111 Project(B14041)Program for Changjiang Scholars and Innovative Research Team in University(IRT-14R33)。
文摘Traditional photosensitizers are predominantly based on various types of polypyrrole macrocycles, which are generally used in homogeneous and/or suspension states. In the present study, a new non-polypyrrole-based photosensitizer(LW-PBI) was developed via the introduction of a nonplanar spirofluorene into a derivative of perylene bisimides(PBI) containing two longalkyl chains. Photophysical studies demonstrated that the compound shows good solubility in common organic solvents, great photochemical stability, and high absorption efficiency in the visible light region. Due to containing of two energetically matchable, independent fluorescent units, the compound as prepared displays strong tendency to form non-fluorescent chargeseparated states under light irradiation in polar solvents. Based on the merits, LW-PBI was examined for its catalytic property in the photo-production of singlet oxygen in film state. Luckily, the compound is an effective photosensitizer in the generation of the active oxygen species as verified by its unique reaction with uric acid(UA). Further studies revealed that the effective photoproduction of singlet oxygen can be also realized via the utilization of a tiny and low-price LED lamp as a light source and as a film support. Detailed studies on the application of the conceptual device as a medical instrument for photodynamic therapy(PDT) are in progress.
