Sintering characteristics of Ca-doped lanthanum chromite [La(Ca)CrO_3] powder, prepared by gel-casting process were studied by measuring density and the evaluation of micro structural information. Bi_2O_3 is found to ...Sintering characteristics of Ca-doped lanthanum chromite [La(Ca)CrO_3] powder, prepared by gel-casting process were studied by measuring density and the evaluation of micro structural information. Bi_2O_3 is found to be an effective sintering additive for this material. The amount of Bi_2O_3 is altered to investigate Bi_2O_3 effect on the properties of La_(0.7)Ca_(0.3)CrO_3. The amount of 10% (mass fraction) Bi_2O_3 is suitable to increase sinter-ability of La_(0.7)Ca_(0.3)CrO_3. Increased concentration of point defects arising form substitution of Bi in La site is the plausible cause of enhanced sintering. Measurement of electrical conductivity and thermal expansion coefficient indicate that the doping of Bi_2O_3 does not have any significant effect on these properties.展开更多
Hole transporting materials(HTMs)play an unparalleled role in heightening the stability and photovoltaic performance of perovskite solar cells(PSCs).The organic small molecule spiro-OMeTAD is frequently utilized for H...Hole transporting materials(HTMs)play an unparalleled role in heightening the stability and photovoltaic performance of perovskite solar cells(PSCs).The organic small molecule spiro-OMeTAD is frequently utilized for HTM in PSCs.However,the raw spiro-OMeTAD without dopant would be harmful to the development of highly efficient PSCs,due to its unsatisfied hole mobility and conductivity.Therefore,we introduce an inorganic dopant(chromium trioxide,CrO_(3))into the lithium-salt doped spiro-OMeTAD.Because of the exclamatory oxidizability of CrO_(3),it can accelerate the oxidation of spiro-OMeTAD and thereby enhancing the hole mobility of HTM.The introduction of CrO_(3) not only substantially decreases the density of defects,but also adjusts spiro-OMeTAD energy band,and thus effectively suppresses the hysteresis and improving stability of PSCs.In the end,we obtained a power conversion efficiency(PCE)as high as 22.6%after doping CrO_(3) in spiro-OMeTAD.The facile,low cost and outstanding photovoltaic performance render CrO_(3) an excellent dopant for HTMs in PSCs.展开更多
Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~...Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~2.46 eV) and shows stable photocatalytic activity under both full range (λ ≥250 nm) and visible light illumination (λ ≥420 nm). A short hydrothermal reaction time is critical to achieve high photocatalytic activity as defects such as Cr^(6+) and Bi^(5+) can be avoided. An AQE as high as 3.66% at 420 nm ± 20 nm has been recorded, warranting promising application in the field of solar energy conversions. DFT calculation reveals the important role of Cr^(3+) cations for visible light sensitivity of Bi_(5)Ti_(3)CrO_(15).展开更多
基金Project supported by the Natural Science Foundation of China (20271047) and the Ministry of Science and Technology of China (G2000026409)
文摘Sintering characteristics of Ca-doped lanthanum chromite [La(Ca)CrO_3] powder, prepared by gel-casting process were studied by measuring density and the evaluation of micro structural information. Bi_2O_3 is found to be an effective sintering additive for this material. The amount of Bi_2O_3 is altered to investigate Bi_2O_3 effect on the properties of La_(0.7)Ca_(0.3)CrO_3. The amount of 10% (mass fraction) Bi_2O_3 is suitable to increase sinter-ability of La_(0.7)Ca_(0.3)CrO_3. Increased concentration of point defects arising form substitution of Bi in La site is the plausible cause of enhanced sintering. Measurement of electrical conductivity and thermal expansion coefficient indicate that the doping of Bi_2O_3 does not have any significant effect on these properties.
基金jointly supported by the National Natural Science Foundation of China(Nos.51972123,U1705256,61804058,21771066)the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University(ZQN-706)the Cultivation Program for Postgraduate in Scientific Research Innovation Ability of Huaqiao University(No.19011081020)。
文摘Hole transporting materials(HTMs)play an unparalleled role in heightening the stability and photovoltaic performance of perovskite solar cells(PSCs).The organic small molecule spiro-OMeTAD is frequently utilized for HTM in PSCs.However,the raw spiro-OMeTAD without dopant would be harmful to the development of highly efficient PSCs,due to its unsatisfied hole mobility and conductivity.Therefore,we introduce an inorganic dopant(chromium trioxide,CrO_(3))into the lithium-salt doped spiro-OMeTAD.Because of the exclamatory oxidizability of CrO_(3),it can accelerate the oxidation of spiro-OMeTAD and thereby enhancing the hole mobility of HTM.The introduction of CrO_(3) not only substantially decreases the density of defects,but also adjusts spiro-OMeTAD energy band,and thus effectively suppresses the hysteresis and improving stability of PSCs.In the end,we obtained a power conversion efficiency(PCE)as high as 22.6%after doping CrO_(3) in spiro-OMeTAD.The facile,low cost and outstanding photovoltaic performance render CrO_(3) an excellent dopant for HTMs in PSCs.
基金This work was supported by the National Natural Science Foundation of China(No.51972233)the Natural Science Foundation of Shanghai(No.19ZR1459200)+1 种基金the Shanghai Science and Technology Commission(No.14DZ2261100)the Fundamental Research Funds for the Central Universities.We also thank Prof.Hongying Zhao for EPR analysis.
文摘Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~2.46 eV) and shows stable photocatalytic activity under both full range (λ ≥250 nm) and visible light illumination (λ ≥420 nm). A short hydrothermal reaction time is critical to achieve high photocatalytic activity as defects such as Cr^(6+) and Bi^(5+) can be avoided. An AQE as high as 3.66% at 420 nm ± 20 nm has been recorded, warranting promising application in the field of solar energy conversions. DFT calculation reveals the important role of Cr^(3+) cations for visible light sensitivity of Bi_(5)Ti_(3)CrO_(15).
