In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) ...In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) reduction was studied under visible light.The as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites show a superior activity for photocatalytic CO_(2) reduction to produce CH4 and CO,with an optimum activity achieved over 0.5 Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6).The obvious superior activity observed over Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites as compared with bare Cs_(2)AgBiBr_(6) and bare Bi_(2)WO_(6) as well as a mechanical mixture of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) can be owe to the fabrication of an efficient S-scheme heterojunction,which accelerates the separation of the photogenerated charge carriers in Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) without sacrificing the high redox capability of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6).This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.展开更多
Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-b...Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-based counterparts.Here,by using photoluminescence(PL),time-resolved photoluminescence(TRPL),and ultrafast transient absorption(TA)measurements,the unbalance between the electron and hole in diffusion and transfer,which limits the performance of the Cs_(2)AgBiBr_(6) PSCs,was further revealed.Considering this issue,a strategy of using the mesoporous TiO_(2) electron transport layer(ETL)to construct a bulk heterojunction in Cs_(2)AgBiBr_(6) PSCs was proposed.Consequently,the PCE had improved by over 24%comparing with that only used compact TiO_(2) ETL.Moreover,based on mesoporous TiO_(2),the unencapsulated Cs_(2)AgBiBr_(6) PSCs maintained 90%of their initial performance after approximately 1200 h of storage in a desiccator(humidity~30%).This work gives further understanding of Cs_(2)AgBiBr_(6) perovskite and demonstrates that a proper design of balancing the electron and hole diffusion can improve device performance.展开更多
In recent years, limited photocatalysis efficiency and wide band gap have hindered the application of TiO_(2) in the field of photocatalysis. A leading star in photocatalysis has been revealed as lead-free Cs_(2)AgBiB...In recent years, limited photocatalysis efficiency and wide band gap have hindered the application of TiO_(2) in the field of photocatalysis. A leading star in photocatalysis has been revealed as lead-free Cs_(2)AgBiBr_(6) double halide perovskite nanocrystals, owing to its strong visible light absorption and tunable band gap. In this work, this photocatalytic process was facilitated by a unique TiO_(2)/Cs_(2)AgBiBr_(6) composite, which was identified as an S-cheme heterojunction. TiO_(2)/Cs_(2)AgBiBr_(6) composite was investigated for its structure and photocatalytic behavior. The results showed that when the perovskite dosage is 40%, the photocatalytic rate of TiO_(2) could be boosted to 0.1369 min^(-1). This paper discusses and proposes the band gap matching, carrier separation, and photocatalytic mechanism of TiO_(2)/Cs_(2)AgBiBr_(6) composites, which will facilitate the generation of new ideas for improving TiO_(2)’s photocatalytic performance.展开更多
The valence band offset between Cs_(2)AgBiBr_(6)and hole transport layer(HTL)is approximately 1.00 e V,which results in high energy loss and is identified as one of the bottle necks of Cs_(2)Ag BiBr_(6)perovskite sola...The valence band offset between Cs_(2)AgBiBr_(6)and hole transport layer(HTL)is approximately 1.00 e V,which results in high energy loss and is identified as one of the bottle necks of Cs_(2)Ag BiBr_(6)perovskite solar cell(PSC)for achieving high power conversion efficiency(PCE).To tackle this problem,we propose the optimization of the energy level alignment by designing and synthesizing novel deep-level hole transport materials(HTMs).The sole introduction of deep-level HTMs successfully reduces the valence band offset between Cs_(2)Ag Bi Br_(6)and HTL,but induces the increased valence band offset at HTL/Au interface,limiting the PCE improvement.To further solve the problem and improve the PCE,the gradient energy level arrangement is constructed by combining the newly developed deep-level HTM 6,6’-(3-((9,9-dimethyl-9H-fluoren-3-yl)(4-methoxyphenyl)amino)thiophene-2,5-diyl)bis(N-(9,9-dimethyl-9H-fluoren-2-yl)-N,9-bis(4-methoxyphenyl)-9H-carbazol-3-amine)(TF)with 2,2’,7,7’-tetrakis(N,N’-dipmethoxyphenylamine)-9,9-spirobifluorene(Spiro-OMeTAD).Through optimization,an impressive PCE of 3.50%with remarkably high open-circuit voltage(V_(oc))and fill factor(FF)is achieved,qualifying it among the best pristine Cs_(2)AgBiBr_(6)PSCs.展开更多
Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counte...Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counterparts.Interest in Cs_(2)B^(I)B^(III)X_(6)motivates intense research into their colloidal nanocrystals(NCs).Recently,Cs_(2)B^(I)B^(III)X_(6)NCs have made great progress in the optical performance via alloying or doping,but there are still great challenges for optoelectronic applications.In this review,the latest advances of Cs_(2)B^(I)B^(III)X_(6)NCs in synthesis approaches,bandgap engineering,photoluminescence(PL)optimization,and applications are summarized.The focus is put upon the composition-property relationships of Cs_(2)B^(I)B^(III)X_(6)NCs,which is approached by discussing the influences of composition variation on the electronic states,carrier dynamics,and optical properties.The challenges and the corresponding improving strategies in the development of high-effective and stable Cs_(2)B^(I)B^(III)X_(6)NCs for device applications are also highlighted.It is believed that this review can deepen the understanding on this burgeoning material system and shed light on their future research directions.展开更多
The response speed of the reported Cs_(2)AgBiBr_(6)-based photodetectors exhibits a wide variation ranging from microseconds to nanoseconds,while the reason is still unclear.Apart from the conventional approaches such...The response speed of the reported Cs_(2)AgBiBr_(6)-based photodetectors exhibits a wide variation ranging from microseconds to nanoseconds,while the reason is still unclear.Apart from the conventional approaches such as reducing effective area,new regulating approaches for response speed improvement have rarely been reported.On the other hand,it is generally believed that ultraviolet(UV)light has negative impact on perovskite devices resulting in performance degradation.In this work,we demonstrated that the response speed of the photodetector with FTO/Cs_(2)AgBiBr_(6)/Au structure can be effectively regulated by utilizing UV light-soaking effect without reducing the device area.Particularly,the decay time is efficiently modulated from 30.1μs to 340 ns.In addition,the−3 dB bandwidth of the device is extended from 5 to 20 kHz.It is worth mentioning that the light current is remarkably boosted by 15 times instead of any attenuation.Furthermore,we prove the universality of UV soaking treatment on Cs_(2)AgBiBr_(6)-based photodetectors with other all-inorganic structures,i.e.,FTO/TiO_(2)/Cs_(2)AgBiBr_(6)/Au,FTO/Cs_(2)AgBiBr_(6)/TiO_(2)/Au and FTO/TiO_(2)/Cs_(2)AgBiBr_(6)/CuSCN/Au.Our results demonstrate a new method to improve the response speed and light current of Cs_(2)AgBiBr_(6)-based perovskite all-inorganic photodetectors.展开更多
Near UV highly luminescent colloidal Cs_(2)NaBiCl_(6)nanocrystals(NCs)were synthesized by a simple low-cost ligand-assisted reprecipitation method.In our strategy,metal chloride precursors were added to the mixture of...Near UV highly luminescent colloidal Cs_(2)NaBiCl_(6)nanocrystals(NCs)were synthesized by a simple low-cost ligand-assisted reprecipitation method.In our strategy,metal chloride precursors were added to the mixture of anti-solvent and ligand at room-temperature.The obtained Cs_(2)NaBiCl_(6)NCs exhibited a bright blue emission with significantly improved photoluminescence quantum yield(PLQY)of 39.05%.The optical properties and stability were greatly enhanced by doping Sb where Cs_(2)NaBi_(0.75)Sb_(0.25)Cl_(6)showed a high PLQY of 46.57%,and both the powder and the colloidal solution exhibited superior stability.展开更多
Due to the better stability and environmentfriendly nature,lead-free halide double perovskites are widely explored as promising materials for next-generation photovoltaics and optoelectronics;however,to date,their pho...Due to the better stability and environmentfriendly nature,lead-free halide double perovskites are widely explored as promising materials for next-generation photovoltaics and optoelectronics;however,to date,their photoelectric device performance is still not satisfactory.Herein,we report a facile solution-process method to synthesize the recently most popular lead-free halide double perovskite,MA_(2)Ag Bi Br_(6),and its all-inorganic counterpart,Cs_(2)Ag Bi Br_(6).The obtained MA_(2)Ag Bi Br_(6)and Cs_(2)Ag Bi Br_(6)films exhibit the microplatelet morphology with excellent crystallinity,distinctly contrasting the ones fabricated by the conventional spin-coating method.Once fabricated into simple photodetectors,the Cs_(2)Ag Bi Br_(6)microplatelet devices yield a respectable responsivity of 245 m A W^(-1) that is two orders of magnitude larger than that of the spin-coated films.More importantly,the response speed of the Cs_(2)Ag Bi Br_(6)microplatelets device is as fast as 145μs,which is higher than most of the values reported in the community of halide double perovskites.When subjected to the thermal stability testing,the Cs_(2)Ag Bi Br_(6)microplatelet device can maintain its initial performance after heating to 160℃ and cooling down to room temperature in the ambient environment.All these results suggest that the facile solution-process method is capable of fabricating high-quality lead-free double perovskites,enabling their advanced device applications.展开更多
文摘In this manuscript,Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites was fabricated via an ultrasonic-assisted process.The activity of the as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites for photocatalytic CO_(2) reduction was studied under visible light.The as-obtained Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites show a superior activity for photocatalytic CO_(2) reduction to produce CH4 and CO,with an optimum activity achieved over 0.5 Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6).The obvious superior activity observed over Cs_(2)AgBiBr_(6)/Bi_(2)WO_(6) nanocomposites as compared with bare Cs_(2)AgBiBr_(6) and bare Bi_(2)WO_(6) as well as a mechanical mixture of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) can be owe to the fabrication of an efficient S-scheme heterojunction,which accelerates the separation of the photogenerated charge carriers in Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6) without sacrificing the high redox capability of Cs_(2)AgBiBr_(6) and Bi_(2)WO_(6).This work demonstrates that the coupling of two photocatalytic materials with staggered band alignment to form an S-scheme heterojunction is an effective strategy to develop efficient photocatalytic systems and also highlights the promising role of using lead free perovskites in photocatalysis.
基金financial support from Macao Science and Technology Development Fund,China(FDCT-0044/2020/A1,FDCT-091/2017/A2,FDCT-014/2017/AMJ)University of Macao Research Grant,China(MYRG2018-00148-IAPME,MYRG2018-00142-IAPME)from University of Macao+2 种基金the Natural Science Foundation of China,China(91733302,61935017)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002)Natural Science Foundation of Guangdong Province,China(2019A1515012186).
文摘Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-based counterparts.Here,by using photoluminescence(PL),time-resolved photoluminescence(TRPL),and ultrafast transient absorption(TA)measurements,the unbalance between the electron and hole in diffusion and transfer,which limits the performance of the Cs_(2)AgBiBr_(6) PSCs,was further revealed.Considering this issue,a strategy of using the mesoporous TiO_(2) electron transport layer(ETL)to construct a bulk heterojunction in Cs_(2)AgBiBr_(6) PSCs was proposed.Consequently,the PCE had improved by over 24%comparing with that only used compact TiO_(2) ETL.Moreover,based on mesoporous TiO_(2),the unencapsulated Cs_(2)AgBiBr_(6) PSCs maintained 90%of their initial performance after approximately 1200 h of storage in a desiccator(humidity~30%).This work gives further understanding of Cs_(2)AgBiBr_(6) perovskite and demonstrates that a proper design of balancing the electron and hole diffusion can improve device performance.
基金the financial support from National Natural Science Foundation of China(Grant Nos.52073164,52103088)Innovation Capability Support Program of Shaanxi(Program No.2021TD-16).
文摘In recent years, limited photocatalysis efficiency and wide band gap have hindered the application of TiO_(2) in the field of photocatalysis. A leading star in photocatalysis has been revealed as lead-free Cs_(2)AgBiBr_(6) double halide perovskite nanocrystals, owing to its strong visible light absorption and tunable band gap. In this work, this photocatalytic process was facilitated by a unique TiO_(2)/Cs_(2)AgBiBr_(6) composite, which was identified as an S-cheme heterojunction. TiO_(2)/Cs_(2)AgBiBr_(6) composite was investigated for its structure and photocatalytic behavior. The results showed that when the perovskite dosage is 40%, the photocatalytic rate of TiO_(2) could be boosted to 0.1369 min^(-1). This paper discusses and proposes the band gap matching, carrier separation, and photocatalytic mechanism of TiO_(2)/Cs_(2)AgBiBr_(6) composites, which will facilitate the generation of new ideas for improving TiO_(2)’s photocatalytic performance.
基金financially supported by the National Natural Science Foundation of China(Nos.22179053,22279046 and 21905119)the Natural Science Excellent Youth Foundation of Jiangsu Provincial(No.BK20220112)+1 种基金the Open Competition Mechanism Project of Carbon Neutrality of Jiangsu Province(No.BE2022026)Zhejiang Province Selected Funding for Postdoctoral Research Projects(No.ZJ2021001)for financial support。
文摘The valence band offset between Cs_(2)AgBiBr_(6)and hole transport layer(HTL)is approximately 1.00 e V,which results in high energy loss and is identified as one of the bottle necks of Cs_(2)Ag BiBr_(6)perovskite solar cell(PSC)for achieving high power conversion efficiency(PCE).To tackle this problem,we propose the optimization of the energy level alignment by designing and synthesizing novel deep-level hole transport materials(HTMs).The sole introduction of deep-level HTMs successfully reduces the valence band offset between Cs_(2)Ag Bi Br_(6)and HTL,but induces the increased valence band offset at HTL/Au interface,limiting the PCE improvement.To further solve the problem and improve the PCE,the gradient energy level arrangement is constructed by combining the newly developed deep-level HTM 6,6’-(3-((9,9-dimethyl-9H-fluoren-3-yl)(4-methoxyphenyl)amino)thiophene-2,5-diyl)bis(N-(9,9-dimethyl-9H-fluoren-2-yl)-N,9-bis(4-methoxyphenyl)-9H-carbazol-3-amine)(TF)with 2,2’,7,7’-tetrakis(N,N’-dipmethoxyphenylamine)-9,9-spirobifluorene(Spiro-OMeTAD).Through optimization,an impressive PCE of 3.50%with remarkably high open-circuit voltage(V_(oc))and fill factor(FF)is achieved,qualifying it among the best pristine Cs_(2)AgBiBr_(6)PSCs.
基金supported by the Natural Science Foundation of Fujian Province(No.2021J01315)Quanzhou Scientific Research Project(No.2021GZ4).
文摘Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counterparts.Interest in Cs_(2)B^(I)B^(III)X_(6)motivates intense research into their colloidal nanocrystals(NCs).Recently,Cs_(2)B^(I)B^(III)X_(6)NCs have made great progress in the optical performance via alloying or doping,but there are still great challenges for optoelectronic applications.In this review,the latest advances of Cs_(2)B^(I)B^(III)X_(6)NCs in synthesis approaches,bandgap engineering,photoluminescence(PL)optimization,and applications are summarized.The focus is put upon the composition-property relationships of Cs_(2)B^(I)B^(III)X_(6)NCs,which is approached by discussing the influences of composition variation on the electronic states,carrier dynamics,and optical properties.The challenges and the corresponding improving strategies in the development of high-effective and stable Cs_(2)B^(I)B^(III)X_(6)NCs for device applications are also highlighted.It is believed that this review can deepen the understanding on this burgeoning material system and shed light on their future research directions.
基金supported by the National Natural Science Foundation of China(51772135 and 52002148)the Ministry of Education of China(6141A02022516)+2 种基金the Fundamental Research Funds for the Central Universities(11619103)Guangdong Basic and Applied Basic Research Foundation(2020A1515011377)the support from China and Germany Postdoctoral Exchange Programthe financial support from Agency for Science,Technology,and Research(A*STAR),Singapore by the AME Individual Research Grants(A1883c0004)。
文摘The response speed of the reported Cs_(2)AgBiBr_(6)-based photodetectors exhibits a wide variation ranging from microseconds to nanoseconds,while the reason is still unclear.Apart from the conventional approaches such as reducing effective area,new regulating approaches for response speed improvement have rarely been reported.On the other hand,it is generally believed that ultraviolet(UV)light has negative impact on perovskite devices resulting in performance degradation.In this work,we demonstrated that the response speed of the photodetector with FTO/Cs_(2)AgBiBr_(6)/Au structure can be effectively regulated by utilizing UV light-soaking effect without reducing the device area.Particularly,the decay time is efficiently modulated from 30.1μs to 340 ns.In addition,the−3 dB bandwidth of the device is extended from 5 to 20 kHz.It is worth mentioning that the light current is remarkably boosted by 15 times instead of any attenuation.Furthermore,we prove the universality of UV soaking treatment on Cs_(2)AgBiBr_(6)-based photodetectors with other all-inorganic structures,i.e.,FTO/TiO_(2)/Cs_(2)AgBiBr_(6)/Au,FTO/Cs_(2)AgBiBr_(6)/TiO_(2)/Au and FTO/TiO_(2)/Cs_(2)AgBiBr_(6)/CuSCN/Au.Our results demonstrate a new method to improve the response speed and light current of Cs_(2)AgBiBr_(6)-based perovskite all-inorganic photodetectors.
基金sponsored by the National Natural Science Foundation of China(Nos.21475021,21427807 and 21777096)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Near UV highly luminescent colloidal Cs_(2)NaBiCl_(6)nanocrystals(NCs)were synthesized by a simple low-cost ligand-assisted reprecipitation method.In our strategy,metal chloride precursors were added to the mixture of anti-solvent and ligand at room-temperature.The obtained Cs_(2)NaBiCl_(6)NCs exhibited a bright blue emission with significantly improved photoluminescence quantum yield(PLQY)of 39.05%.The optical properties and stability were greatly enhanced by doping Sb where Cs_(2)NaBi_(0.75)Sb_(0.25)Cl_(6)showed a high PLQY of 46.57%,and both the powder and the colloidal solution exhibited superior stability.
基金financially supported by the Research Fellow Scheme(RFS2021-1S04)the Theme-based Research(T42-103/16-N)of the Research Grants Council of Hong Kong SAR,ChinaFoshan Innovative and Entrepreneurial Research Team Program(2018IT100031)。
文摘Due to the better stability and environmentfriendly nature,lead-free halide double perovskites are widely explored as promising materials for next-generation photovoltaics and optoelectronics;however,to date,their photoelectric device performance is still not satisfactory.Herein,we report a facile solution-process method to synthesize the recently most popular lead-free halide double perovskite,MA_(2)Ag Bi Br_(6),and its all-inorganic counterpart,Cs_(2)Ag Bi Br_(6).The obtained MA_(2)Ag Bi Br_(6)and Cs_(2)Ag Bi Br_(6)films exhibit the microplatelet morphology with excellent crystallinity,distinctly contrasting the ones fabricated by the conventional spin-coating method.Once fabricated into simple photodetectors,the Cs_(2)Ag Bi Br_(6)microplatelet devices yield a respectable responsivity of 245 m A W^(-1) that is two orders of magnitude larger than that of the spin-coated films.More importantly,the response speed of the Cs_(2)Ag Bi Br_(6)microplatelets device is as fast as 145μs,which is higher than most of the values reported in the community of halide double perovskites.When subjected to the thermal stability testing,the Cs_(2)Ag Bi Br_(6)microplatelet device can maintain its initial performance after heating to 160℃ and cooling down to room temperature in the ambient environment.All these results suggest that the facile solution-process method is capable of fabricating high-quality lead-free double perovskites,enabling their advanced device applications.
