ABSTRACT
The miniaturization of 3D depth camera systems to reduce cost and power consumption is essential for their application in electrical devices that are trending toward smaller sizes (such as smartphones and unmanned aerial systems) and in other applications that cannot be realized via conventional approaches. Currently, equipment exists for a wide range of depth-sensing devices, including stereo vision, structured light, and time-of-flight. This paper reports on a miniaturized 3D depth camera based on a light field camera (LFC) configured with a single aperture and a micro-lens array (MLA). The single aperture and each micro-lens of the MLA serve as multi-camera systems for 3D surface imaging. To overcome the optical alignment challenge in the miniaturized LFC system, the MLA was designed to focus by attaching it to an image sensor. Theoretical analysis of the optical parameters was performed using optical simulation based on Monte Carlo ray tracing to find the valid optical parameters for miniaturized 3D camera systems. Moreover, we demonstrated multi-viewpoint image acquisition via a miniaturized 3D camera module integrated into a smartphone.
ABSTRACT
In streamlined multipurpose applications for light management and protection, encapsulants are merged with photonic crystal structures into solar modules. We present an edge-located 1D grating, attachable polymer on the top of a photovoltaic module to provide a strategy for capturing solar light and improving cell efficiency. Large-area solar arrays suffer from space utilization problems due to nonactive area. The introduction of periodically patterned gratings with specific geometric range is highly preferred to redirect the light toward photovoltaic active areas. To realize optimized broadband light diffraction for solar devices, the theoretical analysis of one-dimensional line patterned diffraction gratings was performed through wave-optic-based simulation. Based on the experimental results, the replica molding-based patterning method was adopted to fabricate the grating polymer for low-cost thin-film production. Also, we demonstrated enhanced light collection by grating patterned encapsulants with improved current density in comparison to the performance of a flat surface.
ABSTRACT
We present the electrical detection of singlet fission in tetracene by using a field-effect transistor (FET). Singlet fission is a photoinduced spin-dependent process, yielding two triplet excitons from the absorption of a single photon. In this study, we engineered a more deterministic platform composed of an organic single crystal FET rather than amorphous or polycrystalline FETs to elucidate spin-dependent processes under magnetic fields. Despite the unipolar operation and relatively high mobility of single crystal tetracene FETs, we were able to manipulate spin dependent processes to detect magnetoconductance (MC) at room temperature by illuminating the FETs and tuning the bias voltage to adjust majority charge carrier density and trap occupancy. In considering the crystalline direction and magnetic field interactions in tetracene, we show the MC response observed in tetracene FETs to be the result of the singlet fission process.
ABSTRACT
Since the first observation of the spin-valve effect through organic semiconductors, efforts to realize novel spintronic technologies based on organic semiconductors have been rapidly growing. However, a complete understanding of spin-polarized carrier injection and transport in organic semiconductors is still lacking and under debate. For example, there is still no clear understanding of major spin-flip mechanisms in organic semiconductors and the role of hybrid metal-organic interfaces in spin injection. Recent findings suggest that organic single crystals can provide spin-transport media with much less structural disorder relative to organic thin films, thus reducing momentum scattering. Additionally, modification of the band energetics, morphology, and even spin magnetic moment at the metal-organic interface by interface engineering can greatly impact the efficiency of spin-polarized carrier injection. Here, progress on efficient spin-polarized carrier injection into organic semiconductors from ferromagnetic metals by using various interface engineering techniques is presented, such as inserting a metallic interlayer, a molecular self-assembled monolayer (SAM), and a ballistic carrier emitter. In addition, efforts to realize long spin transport in single-crystalline organic semiconductors are discussed. The focus here is on understanding and maximizing spin-polarized carrier injection and transport in organic semiconductors and insight is provided for the realization of emerging organic spintronics technologies.
ABSTRACT
We report a unique case of synchronous double primary gastric cancer consisting of adenocarcinoma components with micropapillary features and composite glandular-endocrine cell carcinoma components. The patient was a 53-year-old man presenting with a 6-month history of epigastric pain and diarrhea. A subtotal gastrectomy was performed. Histologically, one tumor was composed of micropapillary carcinoma components (50%) with tight clusters of micropapillary aggregates lying in the empty spaces, admixed with moderately differentiated adenocarcinoma components. MUC-1 was expressed at the stromal edge of the micropapillary component. The other tumor was composed of atypical carcinoid-like neuroendocrine carcinoma (50%), adenocarcinoid (30%), and adenocarcinoma components (20%). The neuroendocrine components were positive for CD56, synaptophysin, chromogranin, and creatine kinase. The adenocarcinoid components were positive for both carcinoembryonic antigen and neuroendocrine markers (amphicrine differentiation). This case is unique, due to the peculiar histologic micropapillary pattern and the histologic spectrum of adenocarcinoma adenocarcinoid-neuroendocrine carcinoma of the synchronous composite tumor.
ABSTRACT
Organic semiconductors hold immense promise for the development of a wide range of innovative devices with their excellent electronic and manufacturing characteristics. Of particular interest are nonmagnetic organic semiconductors that show unusual magnetic field effects (MFEs) at small subtesla field strength that can result in substantial changes in their optoelectronic and electronic properties. These unique phenomena provide a tremendous opportunity to significantly impact the functionality of organic-based devices and may enable disruptive electronic and spintronic technologies. Here, we present an approach to vary the MFEs on the electrical resistance of organic-based systems in a simple yet reliable fashion. We experimentally modify the interfacial characteristics by adding a self-assembled monolayer between the metal electrode and the organic semiconductor, thus enabling the tuning of competing MFE mechanisms coexisting in organic semiconductors. This approach offers a robust method for tuning the magnitude and sign of magnetoresistance in organic semiconductors without compromising the ease of processing.
ABSTRACT
Using long-distance lateral devices, spin transport near the interface of Si and its native oxide (SiO(2)) is studied by spin-valve measurements in an in-plane magnetic field and spin precession measurements in a perpendicular magnetic field at 60 K. As electrons are attracted to the interface by an electrostatic gate, we observe shorter average spin transit times and an increase in spin coherence, despite a reduction in total spin polarization. This behavior, which is in contrast with the expected exponential depolarization seen in bulk transport devices, is explained using a transform method to recover the empirical spin current transit-time distribution and a simple two-stage drift-diffusion model. We identify strong interface-induced spin depolarization (reducing the spin lifetime by over 2 orders of magnitude from its bulk transport value) as the consistent cause of these phenomena.
