Controllable Spin Switching in a Single-Molecule Magnetic Tunneling Junction

A new type of spin-current filter is proposed that consists of a single-molecule magnet (SMM) coupled to two normal metal electrodes. It is shown that this tunneling junction can generate a highly spin-polarized current, whose spin polarization can be switched by means of magnetic fields and gate voltages applied to the SMM. This spin switching in the SMM tunnel junction arises from spin-selective single-electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. The electron current spectrum is still spin polarized in the absence of an external magnetic field, which can help to judge whether the molecule’s spin state has reached the ground-state doublet $$|\pm S\rangle$$ | ± S ⟩ . This device can be realized with current technologies and may have practical use in spintronics and quantum information.

Controllable spin switching in a single-molecule magnetic tunneling junction

A new type of spin-current filter is proposed that consists of a single molecule magnet (SMM) coupled to two normal metal electrodes. It is shown that this tunneling junction can generate a highly spin-polarized current, whose spin polarization can be switched by means of magnetic fields and gate voltages applied to the SMM. This spin switching in the SMM tunnel junction arises from spin-selective single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. The electron current spectrum is still spin polarized in the absence of an external magnetic field, which can help to judge whether the molecule’s spin state has reached the ground-state doublet |± S > . This device can be realized with current technologies and may have practical use in spintronics and quantum information.

Controllable spin switch in a single-molecule magnet tunneling junction

A new type of spin-current filter is proposed, which consists of a single-molecule magnet (SMM) coupled to two normal metal electrodes. It is shown that this tunneling junction can generate a highly spin-polarized current, whose spin polarization can be switched by the magnetic field and gate voltage applied to the SMM. Such a spin switching in the SMM tunnel junction arises from the spin-selected single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. And the electron current spectrum in absences of external magnetic field is still spin-polarized, which can help us to judge if the molecule’s spin state has reach to the ground-state doublet |±S). This device can be realized with current technologies and may have practical use in spintronics and quantum information.PACS numbers: 72.25.-b, 75.50.Xx, 85.75.-d

A temperature dependent study on charge dynamics in organic molecular device: Effect of shallow traps on space charge limited behavior

Shallow traps play a significant role in influencing charge dynamics through organic molecular thin films, such as pentacene. Sandwich cells of pentacene capped by gold electrodes are an excellent specimen to study the nature of underlying charge dynamics. In this paper, self-consistent numerical simulation of I–V characteristics is performed at various temperatures. The results have revealed negative value of Poole Frenkel coefficient. The location of trap energy level is found to be located at 0.24 eV above the highest occupied molecular orbit (HOMO) level of pentacene. Other physical parameters related to trap levels, such as density of states due to traps and effective carrier density due to traps, have also been estimated in this study.

White Electroluminescence Using Eu-Complexed Copolymer as the Red Unit

Europium complexes exhibited intense red fluorescence with a narrow spectral bandwidth. But non-uniform blending or dispersion of complex resulted in phase separation, decomposition and inefficient energy transfer to reduce emission efficiency. The complexes were covalently attached to the main chain of polymers, which improved film quality and solubility. Eu (TTA)2(AA)(TPPO)2 as europium complex monomer (ECM) was prepared by Eu3+ coordinating with triphenylphosphine oxide (TPPO), acrylic acid (AA) and 2-thenoyltrifluoroacetone (TTA). Fluorescent Polymer marked as p1-30 (molar ratio for ECM/N-vinylcarbazole (NVK), 1/30) was synthesized. The emissions of ECM and p1-30 peaked at ca. 610 nm. The highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energy levels were-5.36 and-1.99 eV. The organic light-emitting devices (OLED) A ITO/PEDOT: PSS/PBD: p1-30/AlQ3/ LiF/Al and B ITO/PEDOT: PSS/PBD: p1-30/BCP/AlQ3/LiF/Al were fabricated. A 4 nm thickness of BCP as a hole-block layer was introduced in Device B to block the movement of holes partly and to reduce the emission from AlQ3. Devices A and B mainly emitted white emission and exhibited luminance of 420 and 315 cd/m2 with Commission International de LEclairage (CIE) coordinates of (0.317, 0.392) and (0.336, 0.380), respectively. The emission from carbazole moieties was suppressed, electroluminescent (EL) spectra revealed that effective intramolecular energy transfer from carbazole unit to europium complex occurred.