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Stability of the positively charged manganese centre in GaAs heterostructures examined theoretically by the effective mass approximation calculation near the Γ critical point
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作者 王丽国 申超 +2 位作者 郑厚植 朱汇 赵建华 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期15-22,共8页
This paper describes an n-i-p-i-n model heterostructure with a manganese (Mn)-doped p-type base region to check the stability of a positively charged manganese A+Mn centre with two holes weakly bound by a negativel... This paper describes an n-i-p-i-n model heterostructure with a manganese (Mn)-doped p-type base region to check the stability of a positively charged manganese A+Mn centre with two holes weakly bound by a negatively charged 3dS(Mn) core of a local spin S = 5/2 in the framework of the effective mass approximation near the F critical point (k -0). By including the carrier screening effect, the ground state energy and the binding energy of the second hole in the positively charged centre A+Mn are calculated within a hole concentration range from 1 ×10^16 cm-3 to 1 × 10^17 cm^-3, which is achievable by biasing the structure under photo-excitation. For comparison, the ground-state energy of a single hole in the neutral AMn centre is calculated in the same concentration range. It turns out that the binding energy of the second hole in the A+Mn centre varies from 9.27 meV to 4.57 meV. We propose that the presence of the A+Mn centre can be examined by measuring the photoluminescence from recombination of electrons in the conduction band with the bound holes in the A+Mn centre since a high frequency dielectric constant of ε∞ = 10.66 can be safely adopted in this case. The novel feature of the ability to tune the impurity level of the A+Mn centre makes it attractive for optically and electrically manipulating local magnetic spins in semiconductors. 展开更多
关键词 charged acceptor centre screening effect exchange interaction
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Ethynyl-linked perylene bisimide based electron acceptors for non-fullerene organic solar cells 被引量:1
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作者 Changshi Yu Yunhua Xu +4 位作者 Shijie Liang Xudong Jiang Guitao Feng Cheng Li Weiwei Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2018年第2期325-327,共3页
In this work, star-shaped perylene bisimide(PBI) derivatives with spiro-aromatic cores linked with ethynyl units were developed as electron acceptors for non-fullerene organic solar cells. The ethynyl linkers were f... In this work, star-shaped perylene bisimide(PBI) derivatives with spiro-aromatic cores linked with ethynyl units were developed as electron acceptors for non-fullerene organic solar cells. The ethynyl linkers were found to enhance the planarity of the conjugated backbone, resulting in high electron mobilities and near-infrared absorption. The ethynyl-linked PBI acceptors showed high power conversion efficiencies(PCEs) up to 4.27% due to the high short-circuit current density(Jsc) of 8.52 mA/cm^2 and fill factor(FF) of 0.59, while the PBI acceptor without ethynyl units provided a low PCE of 3.57% in nonfullerene solar cells. The results demonstrate that ethynyl units can be applied into designing new PBI electron acceptors with improved charge transport properties and photovoltaic performance. 展开更多
关键词 Electron acceptor Non-fullerene organic solar cells Perylene bisimide charge transport Ethynyl
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