混合卤化物钙钛矿量子点CsPbBr x I 3-x的带隙高度可调,是光伏和光电领域有广泛用途的纳米材料.在激光连续照射下发生的相分离会降低光电器件的效率,严重影响混合卤化物钙钛矿纳米晶在器件中的应用.本文制备了CsPbBr 1.5 I 1.5和CsPbBr...混合卤化物钙钛矿量子点CsPbBr x I 3-x的带隙高度可调,是光伏和光电领域有广泛用途的纳米材料.在激光连续照射下发生的相分离会降低光电器件的效率,严重影响混合卤化物钙钛矿纳米晶在器件中的应用.本文制备了CsPbBr 1.5 I 1.5和CsPbBrI 2钙钛矿量子点薄膜,对激光激发下的相分离行为与卤化物组成比例、光照时间、激光功率和旋涂浓度的关系进行了研究.研究发现:在不同光照时间、激光功率和旋涂浓度条件下,CsPbBr 1.5 I 1.5量子点薄膜都产生了光谱蓝移的相分离,随后在黑暗下放置一段时间后再次进行测量,发现这种相分离是可逆的;而制备的CsPbBrI 2量子点薄膜在不同功率、光照时间、旋涂浓度下都很稳定,没有发生相分离,光谱只有略微蓝移.展开更多
The focusing of a radially polarized beam without annular apodization ora phase filter at the entrance pupil of the objective results in a wide focus and low purity of the longitudinally polarized component. However, ...The focusing of a radially polarized beam without annular apodization ora phase filter at the entrance pupil of the objective results in a wide focus and low purity of the longitudinally polarized component. However, the presence of a physical annular apodization or phase filter makes some applications more difficult or even impossible. We propose a radially polarized and amplitude-modulated annular multi-Gaussian beam mode. Numerical simulation shows that it can be focused into a sharper focal spot of 0.125λ2 without additional apodizations or filters. The beam quality describing the purity of longitudinally polarized component is up to 86%.展开更多
The influence of thermal effect on the energy conversion efficiency of concentrating photovoltaic system for multi-junction GaInP/GaAs/Ge thin-film solar cell is analyzed experimentally.With the increment of operation...The influence of thermal effect on the energy conversion efficiency of concentrating photovoltaic system for multi-junction GaInP/GaAs/Ge thin-film solar cell is analyzed experimentally.With the increment of operation temperature,the maximal energy conversion efficiency and optimal loaded resistor will be changed.Under the condition of operation temperature lower than 90℃.this influence of thermal effect is very small.However,when the operation temperature exceeds 90℃,the maximal conversion efficiency of the cells will decrease sharply,and contrarily the corresponding optimal loaded resistor will increase quickly.Then the system performance will degenerate badly and a thermal management will be necessary.展开更多
A novel scheme is proposed to transform an ultra-short optical pulse to a millimeter-wave frequencymodulated pulse by using the cascaded all-pass cavities （APCs）. The envelope waveform of the generated pulse train i...A novel scheme is proposed to transform an ultra-short optical pulse to a millimeter-wave frequencymodulated pulse by using the cascaded all-pass cavities （APCs）. The envelope waveform of the generated pulse train is calculated, showing effective improvement by APC cascading. The extinction ratio is analyzed with different input pulses, different cavity reflectivities, and different cascading numbers. It is shown that the cascading does not introduce much effect on the extinction ratio. Two designs by using Gires-Tournois cavity and waveguide ring resonators are proposed to realize the cascaded APC.展开更多
We propose two design methods of concentric multi-belt pure phase apodizer and phase modulation func- tions for generating two ring-shaped focuses by focusing the linearly polarized doughnut-shaped beam with a high nu...We propose two design methods of concentric multi-belt pure phase apodizer and phase modulation func- tions for generating two ring-shaped focuses by focusing the linearly polarized doughnut-shaped beam with a high numerical aperture objective. The phase modulation functions for odd and even belt are verified effectively by numerical simulation. The distance of the two focuses and the position of each focus can be controlled or separately adjusted by the use of liquid crystal spatial phase modulation. It could be useful in optical trapping, particle stacking, alignment and transportation.展开更多
文摘混合卤化物钙钛矿量子点CsPbBr x I 3-x的带隙高度可调,是光伏和光电领域有广泛用途的纳米材料.在激光连续照射下发生的相分离会降低光电器件的效率,严重影响混合卤化物钙钛矿纳米晶在器件中的应用.本文制备了CsPbBr 1.5 I 1.5和CsPbBrI 2钙钛矿量子点薄膜,对激光激发下的相分离行为与卤化物组成比例、光照时间、激光功率和旋涂浓度的关系进行了研究.研究发现:在不同光照时间、激光功率和旋涂浓度条件下,CsPbBr 1.5 I 1.5量子点薄膜都产生了光谱蓝移的相分离,随后在黑暗下放置一段时间后再次进行测量,发现这种相分离是可逆的;而制备的CsPbBrI 2量子点薄膜在不同功率、光照时间、旋涂浓度下都很稳定,没有发生相分离,光谱只有略微蓝移.
基金supported by the National Natural Science Foundation of China(Grant No.11074105)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2010AM038)+1 种基金the Precision Instruments Upgrade Transforming Fund of Shandong Province,China(Grant No.2010GJC20808-16)the Research Fund of Education Department of Shandong Province,China (Grant No.J11LA11)
文摘The focusing of a radially polarized beam without annular apodization ora phase filter at the entrance pupil of the objective results in a wide focus and low purity of the longitudinally polarized component. However, the presence of a physical annular apodization or phase filter makes some applications more difficult or even impossible. We propose a radially polarized and amplitude-modulated annular multi-Gaussian beam mode. Numerical simulation shows that it can be focused into a sharper focal spot of 0.125λ2 without additional apodizations or filters. The beam quality describing the purity of longitudinally polarized component is up to 86%.
基金supported by the Shanghai Rising-Star Program(No.09QB1400700) the Knowledge Innovation Program of the Chinese Academy of Sciences(No. 0903531)
文摘The influence of thermal effect on the energy conversion efficiency of concentrating photovoltaic system for multi-junction GaInP/GaAs/Ge thin-film solar cell is analyzed experimentally.With the increment of operation temperature,the maximal energy conversion efficiency and optimal loaded resistor will be changed.Under the condition of operation temperature lower than 90℃.this influence of thermal effect is very small.However,when the operation temperature exceeds 90℃,the maximal conversion efficiency of the cells will decrease sharply,and contrarily the corresponding optimal loaded resistor will increase quickly.Then the system performance will degenerate badly and a thermal management will be necessary.
基金supported by the National Natural Science Foundation of China under Grant No.60871067
文摘A novel scheme is proposed to transform an ultra-short optical pulse to a millimeter-wave frequencymodulated pulse by using the cascaded all-pass cavities （APCs）. The envelope waveform of the generated pulse train is calculated, showing effective improvement by APC cascading. The extinction ratio is analyzed with different input pulses, different cavity reflectivities, and different cascading numbers. It is shown that the cascading does not introduce much effect on the extinction ratio. Two designs by using Gires-Tournois cavity and waveguide ring resonators are proposed to realize the cascaded APC.
文摘We propose two design methods of concentric multi-belt pure phase apodizer and phase modulation func- tions for generating two ring-shaped focuses by focusing the linearly polarized doughnut-shaped beam with a high numerical aperture objective. The phase modulation functions for odd and even belt are verified effectively by numerical simulation. The distance of the two focuses and the position of each focus can be controlled or separately adjusted by the use of liquid crystal spatial phase modulation. It could be useful in optical trapping, particle stacking, alignment and transportation.
