We built an ideal perovskite solar cell model and investigated the effects of defect states on the so- lar cell＇s performance. The verities of defect states with a different energy level in the band gap and those in ...We built an ideal perovskite solar cell model and investigated the effects of defect states on the so- lar cell＇s performance. The verities of defect states with a different energy level in the band gap and those in the absorption layer CH3NH3PbI3 （MAPbI3）, the interface between the buffer layer/MAPbI3, and the interface be- tween the hole transport material （HTM） and MAPbI3, were studied. We have quantitatively analyzed these effects on perovskite solar cells＇ performance parameters. They are open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency. We found that the performances of perovskite solar cells change worse with defect state density increasing, but when defect state density is lower than 1016 cm^-3, the effects are small. Defect states in the absorption layer have much larger effects than those in the adjacent interface layers. The per-ovskite solar cells have better performance as its working temperature is reduced. When the thickness of MAPbI3 is about 0.3μm, perovskite solar cells show better comprehensive performance, while the thickness 0.05μm for Spiro-OMeTAD is enough.展开更多
Classical atomistic simulations based on the lattice dynalnics theory and the Born core-shell model are performed to systematically study the crystal structure and thermal properties of high-k Hfl-xSixO2. The coeffici...Classical atomistic simulations based on the lattice dynalnics theory and the Born core-shell model are performed to systematically study the crystal structure and thermal properties of high-k Hfl-xSixO2. The coefficients of thermal expansion, specific heat, Griineisen parameters, phonon densities of states and Debye temperatures are calculated at different temperatures and for different Si-doping concentrations. With the increase of the Si-doping concentration, the lattice constant decreases. At the same time, both the coefficient of thermal expansion and the specific heat at a constant volume of Hf1-mSixO2 also decreases. The Griineisen parameter is about 0.95 at temperatures less than 100 K. Compared with Si-doped HfO2, pure HfO2 has a higher Debye temperature when the temperature is less than 25 K, while it has lower Debye temperature when the temperature is higher than 50 K. Some simulation results fit well with the experimental data. We expect that our results will be helpful for understanding the local lattice structure and thermal properties of Hf1-mSixO2.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11164014,11364025)the Gansu Science and Technology Pillar Program(No.1204GKCA057)the Gansu Supercomputer Center
文摘We built an ideal perovskite solar cell model and investigated the effects of defect states on the so- lar cell＇s performance. The verities of defect states with a different energy level in the band gap and those in the absorption layer CH3NH3PbI3 （MAPbI3）, the interface between the buffer layer/MAPbI3, and the interface be- tween the hole transport material （HTM） and MAPbI3, were studied. We have quantitatively analyzed these effects on perovskite solar cells＇ performance parameters. They are open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency. We found that the performances of perovskite solar cells change worse with defect state density increasing, but when defect state density is lower than 1016 cm^-3, the effects are small. Defect states in the absorption layer have much larger effects than those in the adjacent interface layers. The per-ovskite solar cells have better performance as its working temperature is reduced. When the thickness of MAPbI3 is about 0.3μm, perovskite solar cells show better comprehensive performance, while the thickness 0.05μm for Spiro-OMeTAD is enough.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10964003 and 11164014)the Natural Science Foundation of Gansu Province, China (Grant No. 096RJZA102)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20096201120002)the China Postdoctoral Science Foundation (Grant Nos. 20100470886 and 201104324)
文摘Classical atomistic simulations based on the lattice dynalnics theory and the Born core-shell model are performed to systematically study the crystal structure and thermal properties of high-k Hfl-xSixO2. The coefficients of thermal expansion, specific heat, Griineisen parameters, phonon densities of states and Debye temperatures are calculated at different temperatures and for different Si-doping concentrations. With the increase of the Si-doping concentration, the lattice constant decreases. At the same time, both the coefficient of thermal expansion and the specific heat at a constant volume of Hf1-mSixO2 also decreases. The Griineisen parameter is about 0.95 at temperatures less than 100 K. Compared with Si-doped HfO2, pure HfO2 has a higher Debye temperature when the temperature is less than 25 K, while it has lower Debye temperature when the temperature is higher than 50 K. Some simulation results fit well with the experimental data. We expect that our results will be helpful for understanding the local lattice structure and thermal properties of Hf1-mSixO2.
