Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand ...Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.展开更多
The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) io...The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) ions in OIHMHs is primarily confined to the low energy region,resulting in yellow or red emissions.To date,there are few reports about green emission of Sb^(3+)-doped OIHMHs.Here,we present a novel approach for regulating the luminescence of Sb^(3+) ions in 0D C_(10)H_(2)_(2)N_(6)InCl_(7)·H_(2)O via hydrogen bond network,in which water molecules act as agents for hydrogen bonding.Sb^(3+)-doped C_(10)H_(2)2N_(6)InCl_(7)·H_(2)O shows a broadband green emission peaking at 540 nm and a high photoluminescence quantum yield(PLQY)of 80%.It is found that the intense green emission stems from the radiative recombination of the self-trapped excitons(STEs).Upon removal of water molecules with heat,C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7) generates yellow emis-sion,attributed to the breaking of the hydrogen bond network and large structural distortions of excited state.Once water molecules are adsorbed by C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7),it can subsequently emit green light.This water-induced reversible emission switching is successfully used for optical security and information encryption.Our findings expand the under-standing of how the local coordination structure influences the photophysical mechanism in Sb^(3+)-doped metal halides and provide a novel method to control the STEs emission.展开更多
Bulk and interface carrier nonradiative recombination losses impede the further improvement of power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs).It is highly necessary to develop multifunct...Bulk and interface carrier nonradiative recombination losses impede the further improvement of power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs).It is highly necessary to develop multifunctional strategy to minimize surface and interface nonradiative recombination losses.Herein,we report a bulk and interface defect passivation strategy via the synergistic effect of anions and cations,where multifunctional potassium sulphate(K_(2)SO_(4))is incorporated at SnO_(2)/perovskite interface.We find that K^(+)ions in K_(2)SO_(4)diffuse into perovskite layer and suppress the formation of bulk defects in perovskite films,and the SO_(4)^(2-)ions remain located at interface via the strong chemical interaction with SnO_(2)layer and perovskite layer,respectively.Through this synergistic modification strategy,effective defect passivation and improved energy band alignment are achieved simultaneously.These beneficial effects are translated into an efficiency increase from 19.45%to 21.18%with a low voltage deficit of0.53 V mainly as a result of boosted open-circuit voltage(V_(oc))after K_(2)SO_(4)modification.In addition,the K_(2)SO_(4)modification contributes to ameliorated stability.The present work provides a route to minimize bulk and interface nonradiative recombination losses for the simultaneous realization of PCE and stability enhancement by rational anion and cation synergistic engineering.展开更多
The NiO_(x)/perovskite interface in NiO_(x)-based inverted perovskite solar cells(PSCs)is one of the main issues that restrict device performance and long-term stability,as the unwanted interfacial defects and undesir...The NiO_(x)/perovskite interface in NiO_(x)-based inverted perovskite solar cells(PSCs)is one of the main issues that restrict device performance and long-term stability,as the unwanted interfacial defects and undesirable redox reactions cause severe interfacial non-radiative recombination and open-circuit voltage(Voc)loss.Herein,a series of self-assembled molecules(SAMs)are employed to bind,bridge,and stabilize the NiO_(x)/perovskite interface by regulating the electrostatic potential.Based on systematically theoretical and experimental studies,4-pyrazolecarboxylic acid(4-PCA)is proven as an efficient molecule to simultaneously passivate the NiO_(x)and perovskite surface traps,release the interfacial tensile stress as well as quench the detrimental interface redox reactions,thus effectively suppressing the interfacial non-radiative recombination and enhancing the quality of perovskite crystals.Consequently,the PSCs with 4-PCA treatment exhibited an eminently increased Voc,leading to a significant increase in power conversion efficiency from 21.28%to 23.77%.Furthermore,the unencapsulated devices maintain 92.6%and 81.3%of their initial PCEs after storing in air with a relative humidity of 20%–30%for 1000 h and heating at 65℃for 500 h in a N_(2)-filled glovebox,respectively.展开更多
Perovskite solar cells(PSCs) have stood out from many photovoltaic technologies due to their flexibility,cost-effectiveness and high-power conversion efficiency(PCE). Nevertheless, the further development of PSCs is g...Perovskite solar cells(PSCs) have stood out from many photovoltaic technologies due to their flexibility,cost-effectiveness and high-power conversion efficiency(PCE). Nevertheless, the further development of PSCs is greatly hindered by the trap-induced non-radiative recombination losses and poor long-term work stability. In the past decade, the huge advancements have been obtained on suppressing nonradiative recombination and enhancing device durability. Among them, the multisite ligands(MSLs) engineering plays a crucial role in precise control and directional modification of functional layers and interfaces,which contributes to markedly increased PCE and lifetimes of PSCs. In view of this, this review summarizes the advances of MSLs in PSCs. From the perspective of functional groups and chemical interaction,the modulation mechanisms of properties of different functional layers and interfaces and device performance via various MSLs are deeply investigated and revealed. Finally, the prospects for the application and development direction of MSLs in PSCs are legitimately proposed.展开更多
All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have received great attention in white light emission because of their outstanding properties.However,their practical application is hindered by poor stability.Here...All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have received great attention in white light emission because of their outstanding properties.However,their practical application is hindered by poor stability.Herein,we propose a simple strategy to synthesize excellent stability and efficient emission of CsPbBr_(3) QDs by using 2-hexyldecanoic acid(DA)as a ligand to replace the regular oleic acid(OA)ligand.Thanks to the strong binding energy between DA ligand and QDs,the modified QDs not only show a high photoluminescence quantum yield(PLQY)of 96%but also exhibit high stability against ethanol and water.Thereby warm white light-emitting diodes(WLEDs)are constructed by combining lig-and modified CsPbBr_(3) QDs with red AgInZnS QDs on blue emitting InGaN chips,exhibiting a color rendering index of 93,a power efficiency of 64.8 lm/W,a CIE coordinate of(0.44,0.42)and correlated color temperature value of 3018 K.In ad-dition,WLEDs based on ligand modified CsPbBr_(3) QDs also exhibit better thermal performance than that of WLEDs based on the regular CsPbBr_(3) QDs.The combination of improved efficiency and better thermal stability with high color quality indicates that the modified CsPbBr_(3) QDs are ideal for WLEDs application.展开更多
The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device s...The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device stability.Here,we report a bottom-up holistic carrier management strategy induced synergistically by multiple chemical bonds to minimize bulk and interfacial energy losses for high-performance perovskite photovoltaics.4-trifluoromethyl-benzamidine hydrochloride(TBHCl)containing–CF_(3),amidine cation and Cl^(-)is in advance incorporated into SnO_(2)colloid solution to realize bottom-up modification.The synergistic effect of multiple functional groups and multiple-bond-induced chemical interaction are revealed theoretically and experimentally.F and Cl^(-)can passivate oxygen vacancy and/or undercoordinated Sn^(4+)defects by coordinating with Sn^(4+).The F can suppress cation migration and modulate crystallization via hydrogen bond with FA^(+),and can passivate lead defects by coordinating with Pb^(2+).The–NH_(2)–C=NH^(+)_(2)and Cl^(-)can passivate cation and anion vacancy defects through ionic bonds with perovskites,respectively.Through TBHCl modification,the suppression of agglomeration of SnO_(2)nanoparticles,bulk and interfacial defect passivation,and release of tensile strains of perovskite films are demonstrated,which resulted in a PCE enhancement from 21.28%to 23.40%and improved stability.With post-treatment,the efficiency is further improved to 23.63%.展开更多
Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal a...Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.展开更多
Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and th...Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and the available perovskites yellow LEDs suffer from the instability. Herein, a pressure-assisted cooling method is proposed to grow lead-free CsCu2I3single crystals, which possess uniform surface morphology and enhanced photoluminescence quantum yield(PLQY) stability, with only 10% PLQY losses after being stored in air after 5000 h.Then, the single crystals used for yellow LEDs without encapsulation exhibit a decent Correlated Color Temperature(CCT) of 4290 K, a Commission Internationale de l’Eclairage(CIE) coordinate of(0.38, 0.41), and an excellent 570-h operating stability under heating temperature of 100°C. Finally, the yellow LEDs facilitate the application in wireless visible light communication(VLC), which show a-3 dB bandwidth of 21.5 MHz and a high achievable data rate of 219.2 Mbps by using orthogonal frequency division multiplexing(OFDM) modulation with adaptive bit loading. The present work not only promotes the development of lead-free single crystals, but also inspires the potential of CsCu2I3in the field of yellow illumination and wireless VLC.展开更多
基金the National Natural Science Foundation of China(Grant No.62375032)the Natural Science Foundation of Chongqing(Grant No.CSTB2023TIADKPX0017)+2 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)the China Postdoctoral Science Foundation(Grant No.BX20230355)the Department of Education of Guizhou Province(Guizhou Teaching and Technology[2023]015)。
文摘Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.
基金National Natural Science Foundation of China(11974063)Graduate research innovation project,School of Optoelectronic Engineering,Chongqing University(GDYKC2023002)+1 种基金Fundamental Research Funds for the Central Universities(2022CDJQY-010)The authors extend their appreciation to the Deputyship for Research and Innovation,Ministry of Education in Saudi Arabia for funding this research work through the project no.(IFKSUOR3-073-9).
文摘The Sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIHMHs).However,the emission of Sb^(3+) ions in OIHMHs is primarily confined to the low energy region,resulting in yellow or red emissions.To date,there are few reports about green emission of Sb^(3+)-doped OIHMHs.Here,we present a novel approach for regulating the luminescence of Sb^(3+) ions in 0D C_(10)H_(2)_(2)N_(6)InCl_(7)·H_(2)O via hydrogen bond network,in which water molecules act as agents for hydrogen bonding.Sb^(3+)-doped C_(10)H_(2)2N_(6)InCl_(7)·H_(2)O shows a broadband green emission peaking at 540 nm and a high photoluminescence quantum yield(PLQY)of 80%.It is found that the intense green emission stems from the radiative recombination of the self-trapped excitons(STEs).Upon removal of water molecules with heat,C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7) generates yellow emis-sion,attributed to the breaking of the hydrogen bond network and large structural distortions of excited state.Once water molecules are adsorbed by C_(10)H_(2)_(2)N_(6)In_(1-x)Sb_(x)Cl_(7),it can subsequently emit green light.This water-induced reversible emission switching is successfully used for optical security and information encryption.Our findings expand the under-standing of how the local coordination structure influences the photophysical mechanism in Sb^(3+)-doped metal halides and provide a novel method to control the STEs emission.
基金financially supported by the Defense Industrial Technology Development Program(JCKY2017110C0654)the National Natural Science Foundation of China(11974063,61904023)the Chongqing Special Postdoctoral Science Foundation(cstc2019jcyj-bsh0026)。
文摘Bulk and interface carrier nonradiative recombination losses impede the further improvement of power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs).It is highly necessary to develop multifunctional strategy to minimize surface and interface nonradiative recombination losses.Herein,we report a bulk and interface defect passivation strategy via the synergistic effect of anions and cations,where multifunctional potassium sulphate(K_(2)SO_(4))is incorporated at SnO_(2)/perovskite interface.We find that K^(+)ions in K_(2)SO_(4)diffuse into perovskite layer and suppress the formation of bulk defects in perovskite films,and the SO_(4)^(2-)ions remain located at interface via the strong chemical interaction with SnO_(2)layer and perovskite layer,respectively.Through this synergistic modification strategy,effective defect passivation and improved energy band alignment are achieved simultaneously.These beneficial effects are translated into an efficiency increase from 19.45%to 21.18%with a low voltage deficit of0.53 V mainly as a result of boosted open-circuit voltage(V_(oc))after K_(2)SO_(4)modification.In addition,the K_(2)SO_(4)modification contributes to ameliorated stability.The present work provides a route to minimize bulk and interface nonradiative recombination losses for the simultaneous realization of PCE and stability enhancement by rational anion and cation synergistic engineering.
基金financially supported by the National Natural Science Foundation of China (U22A2078)Fundamental Research Funds for the Central Universities (2022CDJQY-007)
文摘The NiO_(x)/perovskite interface in NiO_(x)-based inverted perovskite solar cells(PSCs)is one of the main issues that restrict device performance and long-term stability,as the unwanted interfacial defects and undesirable redox reactions cause severe interfacial non-radiative recombination and open-circuit voltage(Voc)loss.Herein,a series of self-assembled molecules(SAMs)are employed to bind,bridge,and stabilize the NiO_(x)/perovskite interface by regulating the electrostatic potential.Based on systematically theoretical and experimental studies,4-pyrazolecarboxylic acid(4-PCA)is proven as an efficient molecule to simultaneously passivate the NiO_(x)and perovskite surface traps,release the interfacial tensile stress as well as quench the detrimental interface redox reactions,thus effectively suppressing the interfacial non-radiative recombination and enhancing the quality of perovskite crystals.Consequently,the PSCs with 4-PCA treatment exhibited an eminently increased Voc,leading to a significant increase in power conversion efficiency from 21.28%to 23.77%.Furthermore,the unencapsulated devices maintain 92.6%and 81.3%of their initial PCEs after storing in air with a relative humidity of 20%–30%for 1000 h and heating at 65℃for 500 h in a N_(2)-filled glovebox,respectively.
基金financially supported by the National Natural Science Foundation of China (62274018)the Xinjiang Construction Corps Key Areas of Science and Technology Research Project (2023AB029)the Key Project of Chongqing Overseas Students Returning to China Entrepreneurship and Innovation Support Plan (cx2023006)。
文摘Perovskite solar cells(PSCs) have stood out from many photovoltaic technologies due to their flexibility,cost-effectiveness and high-power conversion efficiency(PCE). Nevertheless, the further development of PSCs is greatly hindered by the trap-induced non-radiative recombination losses and poor long-term work stability. In the past decade, the huge advancements have been obtained on suppressing nonradiative recombination and enhancing device durability. Among them, the multisite ligands(MSLs) engineering plays a crucial role in precise control and directional modification of functional layers and interfaces,which contributes to markedly increased PCE and lifetimes of PSCs. In view of this, this review summarizes the advances of MSLs in PSCs. From the perspective of functional groups and chemical interaction,the modulation mechanisms of properties of different functional layers and interfaces and device performance via various MSLs are deeply investigated and revealed. Finally, the prospects for the application and development direction of MSLs in PSCs are legitimately proposed.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.11974063,11904156)Postdoctoral Science Foundation of China(No.2019M653336).The calcu-lations were done at the Center for Computational Science and Engineering of Southern University of Science and Technology(SUSTech).
文摘All-inorganic CsPbBr_(3) perovskite quantum dots(QDs)have received great attention in white light emission because of their outstanding properties.However,their practical application is hindered by poor stability.Herein,we propose a simple strategy to synthesize excellent stability and efficient emission of CsPbBr_(3) QDs by using 2-hexyldecanoic acid(DA)as a ligand to replace the regular oleic acid(OA)ligand.Thanks to the strong binding energy between DA ligand and QDs,the modified QDs not only show a high photoluminescence quantum yield(PLQY)of 96%but also exhibit high stability against ethanol and water.Thereby warm white light-emitting diodes(WLEDs)are constructed by combining lig-and modified CsPbBr_(3) QDs with red AgInZnS QDs on blue emitting InGaN chips,exhibiting a color rendering index of 93,a power efficiency of 64.8 lm/W,a CIE coordinate of(0.44,0.42)and correlated color temperature value of 3018 K.In ad-dition,WLEDs based on ligand modified CsPbBr_(3) QDs also exhibit better thermal performance than that of WLEDs based on the regular CsPbBr_(3) QDs.The combination of improved efficiency and better thermal stability with high color quality indicates that the modified CsPbBr_(3) QDs are ideal for WLEDs application.
基金financially supported by the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074)the Natural Science Foundation of Chongqing(cstc2020jcyj-msxm X0629)。
文摘The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device stability.Here,we report a bottom-up holistic carrier management strategy induced synergistically by multiple chemical bonds to minimize bulk and interfacial energy losses for high-performance perovskite photovoltaics.4-trifluoromethyl-benzamidine hydrochloride(TBHCl)containing–CF_(3),amidine cation and Cl^(-)is in advance incorporated into SnO_(2)colloid solution to realize bottom-up modification.The synergistic effect of multiple functional groups and multiple-bond-induced chemical interaction are revealed theoretically and experimentally.F and Cl^(-)can passivate oxygen vacancy and/or undercoordinated Sn^(4+)defects by coordinating with Sn^(4+).The F can suppress cation migration and modulate crystallization via hydrogen bond with FA^(+),and can passivate lead defects by coordinating with Pb^(2+).The–NH_(2)–C=NH^(+)_(2)and Cl^(-)can passivate cation and anion vacancy defects through ionic bonds with perovskites,respectively.Through TBHCl modification,the suppression of agglomeration of SnO_(2)nanoparticles,bulk and interfacial defect passivation,and release of tensile strains of perovskite films are demonstrated,which resulted in a PCE enhancement from 21.28%to 23.40%and improved stability.With post-treatment,the efficiency is further improved to 23.63%.
基金financially supported by the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074 and 2021CDJQY-022)Natural Science Foundation of Chongqing(cstc2020jcyjmsxmX0629)。
文摘Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.
基金This work is funded by National Natural Science Foundation of China(Nos.61904023,11974063)Fundamental Research Funds for the Cen-tral Universities(2021CDJQY-022)Natural Science Foundation of Chongqing(No.cstc2019jcyj-bshX0078,cstc2020jcyj-jqX0028).
文摘Yellow light-emitting diodes(LEDs) as soft light have attracted abundant attention in lithography room, museum and art gallery. However, the development of efficient yellow LEDs lags behind green and blue LEDs, and the available perovskites yellow LEDs suffer from the instability. Herein, a pressure-assisted cooling method is proposed to grow lead-free CsCu2I3single crystals, which possess uniform surface morphology and enhanced photoluminescence quantum yield(PLQY) stability, with only 10% PLQY losses after being stored in air after 5000 h.Then, the single crystals used for yellow LEDs without encapsulation exhibit a decent Correlated Color Temperature(CCT) of 4290 K, a Commission Internationale de l’Eclairage(CIE) coordinate of(0.38, 0.41), and an excellent 570-h operating stability under heating temperature of 100°C. Finally, the yellow LEDs facilitate the application in wireless visible light communication(VLC), which show a-3 dB bandwidth of 21.5 MHz and a high achievable data rate of 219.2 Mbps by using orthogonal frequency division multiplexing(OFDM) modulation with adaptive bit loading. The present work not only promotes the development of lead-free single crystals, but also inspires the potential of CsCu2I3in the field of yellow illumination and wireless VLC.
