The role of bathophenanthroline （Bphen） as a buffer layer inserted between fullerene （C60） and Ag cathode in organic photovoltaic （OPV） cell was discussed. By introducing Bphen as a buffer layer with thicknes fr...The role of bathophenanthroline （Bphen） as a buffer layer inserted between fullerene （C60） and Ag cathode in organic photovoltaic （OPV） cell was discussed. By introducing Bphen as a buffer layer with thicknes from 0 to 2.5 nm, the power conversion efficiency of the OPV cell based on copper phthalocyanine （CuPc） and C60 was increased from 0.87% to 2.25% under AM 1.5 solar illumination at an intensity of 100 mW/cm^2, which was higher than that of bathocuproine used as a buffer layer. The photocurrent-voltage characteristics showed that Bphen effectively improves electron transport through C60 layer into Ag electrode and leads to balance charge carrier transport capability. The influence of Bphen thickness on OPV cells was also investigated. Furthermore, the absorption spectrum shows that an additional Bphen layer enhances the light harvest capability of CuPc/C60.展开更多
We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of den...We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of density matrix. In presence of a strong THz field, the optical transitions in quantum well subbands are altered by the THz field. The alteration has a direct impact on the optical absorption and the charge density. The excitonic peak splitting and THz optical sideband in the absorption spectra show up when changing the THz field intensity and/or frequency. The Autler-Towns splitting is a result from the THz nonlinear dynamics of confined excitons. On the other hand, the carrier charge density is created as wave packets formed by coherent superposition of several eigenstates. The charge density exhibitsquantum beats for short pulses and/or wider wells and is modulated by the THz field.展开更多
Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the sub...Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the substrates. The in-plane dielectric constant and loss of HMO films were measured as functions of temperature(80–300 K) and frequency(120 Hz–100 kHz) by using coplanar interdigital electrodes. Two thermally activated dielectric relaxations were found, and the respective peaks shifted to higher temperatures as the measuring frequency increased. The in-plane dielectric properties of epitaxial orthorhombic HMO films were considered as universal dielectric response behavior, and the dipolar effects and the hopping conductivity induced by the charge carriers were used to explain the results.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.60736005 and No.60425101-1）, the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （No.60721001）, the Provincial Program （No.9140A02060609DZ0208）, the Program for New Century Excellent Talents in University （No.NCET- 06-0812）, the Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry （No.GGRYJJ08P 05）, and the Young Excellence Project of Sichuan （No.09ZQ026-074）.
文摘The role of bathophenanthroline （Bphen） as a buffer layer inserted between fullerene （C60） and Ag cathode in organic photovoltaic （OPV） cell was discussed. By introducing Bphen as a buffer layer with thicknes from 0 to 2.5 nm, the power conversion efficiency of the OPV cell based on copper phthalocyanine （CuPc） and C60 was increased from 0.87% to 2.25% under AM 1.5 solar illumination at an intensity of 100 mW/cm^2, which was higher than that of bathocuproine used as a buffer layer. The photocurrent-voltage characteristics showed that Bphen effectively improves electron transport through C60 layer into Ag electrode and leads to balance charge carrier transport capability. The influence of Bphen thickness on OPV cells was also investigated. Furthermore, the absorption spectrum shows that an additional Bphen layer enhances the light harvest capability of CuPc/C60.
基金the National Fund for Distinguished Young Scholars of China under，国家自然科学基金，国家重点基础研究发展计划(973计划)，上海市科委资助项目
文摘We theoretically investigate the optical absorption spectra and charge density by subjecting a GaAs quantum well to both an intense terahertz (THz)-frequency driving field and an optical pulse within the theory of density matrix. In presence of a strong THz field, the optical transitions in quantum well subbands are altered by the THz field. The alteration has a direct impact on the optical absorption and the charge density. The excitonic peak splitting and THz optical sideband in the absorption spectra show up when changing the THz field intensity and/or frequency. The Autler-Towns splitting is a result from the THz nonlinear dynamics of confined excitons. On the other hand, the carrier charge density is created as wave packets formed by coherent superposition of several eigenstates. The charge density exhibitsquantum beats for short pulses and/or wider wells and is modulated by the THz field.
基金supported by Shandong Province Natural Science Foundation of China(Grant No.ZR2011AM014)
文摘Orthorhombic HoMnO3(HMO) thin films were grown epitaxially on LaAlO3(001) substrates by using pulsed laser deposition technique. The films showed perfect orthorhombic crystallization and were well-aligned with the substrates. The in-plane dielectric constant and loss of HMO films were measured as functions of temperature(80–300 K) and frequency(120 Hz–100 kHz) by using coplanar interdigital electrodes. Two thermally activated dielectric relaxations were found, and the respective peaks shifted to higher temperatures as the measuring frequency increased. The in-plane dielectric properties of epitaxial orthorhombic HMO films were considered as universal dielectric response behavior, and the dipolar effects and the hopping conductivity induced by the charge carriers were used to explain the results.
