Wide Field Magnetic Luminescence Imaging

Abstract

This study demonstrates how magnetic-field-dependent luminescence from organic films can be used to image the magnetic configuration of an underlying sample. The organic semiconductors tetracene and rubrene exhibit singlet exciton fission, which is a process sensitive to magnetic fields. Here, thin films of these materials were characterized using photoluminescence spectrometry, atomic force microscopy, and photoluminescence magnetometry. The luminescence from these substrate-bound thin films is imaged to reveal the magnetic configuration of underlying Nd-Fe-B magnets. The tendency of rubrene to form amorphous films and produce large changes in photoluminescence under an applied magnetic field makes it more appropriate for magnetic field imaging than tetracene. This demonstration can be extended in the future to allow simple microscopic imaging of magnetic structure.

Resolving the Spatial Variation and Correlation of Hyperfine Spin Properties in Organic Light‐Emitting Diodes

“…The results described above have implications for the reproducibility of organic‐based technologies in a wide range of applications—it places limits on the precision for spatially resolved magnetic field effect sensors, [ 32 ] it provides a limit on the size of regions in which cooperative phenomena (such as the spin‐Dicke effect [ 41 ] ) are likely to occur on, and it points to materials challenges for the miniaturization and scalability of spin‐based devices below current state‐of‐the‐art AMOLED pixel sizes. Further development of this experimental approach will also enable the investigation of spatiotemporal nuclear‐spin dynamics in a range of organic systems used in quantum technologies.…”

“…[ 26,29 ] If this is not a good assumption, it will present a significant challenge as we move toward high spatial resolution of magnetic fields [ 30,31 ] in organic devices. [ 32,33 ] We will demonstrate in the following sections that the Overhauser field indeed shows substantial intra‐device variation by spatially resolving the magnetoluminescence effect exhibited by both a copolymer Super Yellow poly(phenylene–vinylene) (SY‐PPV) and a small‐molecule tris‐(8‐hydroxyquinoline) aluminum (Alq 3 ) OLED. As the Overhauser field is central to a wide range of spin‐enabled functionality in organic devices, this variation presents a fundamental challenge for efforts to miniaturize and integrate such devices.…”

Achievement of High-Level Reverse Intersystem Crossing in Rubrene-Doped Organic Light-Emitting Diodes

“…6,9 Although the MEL line-shapes (Figure 2a,b) of these two devices are very different, as depicted in Figure 2c, their normalized EL spectra are still the same, and both of them originate from an emission of rubrene molecules. 6,9,19 Therefore, to disclose the origin of B-mediated RISC-like curves in 10% rubrene-doped device, we further measured the MC curve of 10% rubrene-doped OLED, as shown in Figure 2d. Interestingly, the LFEs of these MC curves show the tendency with the ISC characteristic (see the dark yellow curve in Figure S1), 9,22 which is completely opposite to the RISC-like property of MEL traces (Figure 2a).…”

Magnetic Field Perturbations to a Soft X-ray-Activated Fe (II) Molecular Spin State Transition

“…This magneticfield-induced perturbation of the low-spin to high-spin state barrier is explored here for [Fe{H 2 B(pz) 2 } 2 (bipy)]. The influence of magnetic fields on the excitation and de-excitation in molecules has been observed before [13][14][15][16][17][18] and is not unique to spin crossover complexes. These latter studies are not of molecular systems, but organics such as anthracene and rubrene where this phenomenon arises due to the coupling of a molecule in the electronic singlet ground state with an adjacent molecule in the first excited singlet state to form a correlated triplet-pair state.…”