A physics-based analytical model is important to understand the working mechanism through process parameters of any innovative material heterostructure. We present an analytical model to calculate the power conversion efficiency of solar cells based on graphene and III-V direct bandgap semiconductors. The model is comprehensively developed by incorporating several current densities obtained from both the generation and recombination processes. Moreover, to obtain a highly efficient Schottky junction solar cell, we propose an optimized structure of graphene/GaAs with lattice-matched passivation and carrier selective layers. The structure has the advantage of surface passivation and photon recycling that reduces interface recombination and ensures more electron–hole pair generation, respectively. It exhibits a theoretical efficiency of >18 % from the analytical model simulation which is later verified by numerical simulation using SCAPS 1D software. The analytical model will provide not only a better understanding of the solar cells’ operation but also a comparative study among them to achieve better efficiency in the future. In addition, the enhanced efficiency of the proposed structure will encourage further research in this field of study.
Significance: X-ray imaging serves as the mainstream imaging in dentistry, but it involves risk of ionizing radiation.
Aim: This study presents the feasibility of indocyanine green-assisted near-infrared fluorescence (ICG-NIRF) dental imaging with 785-nm NIR laser in the first (ICG-NIRF-I: 700 to 1000 nm) and second (ICG-NIRF-II: 1000 to 1700 nm) NIR wavelengths.
Approach: Sprague Dawley rats with different postnatal days were used as animal models. ICG, as a fluorescence agent, was delivered to dental structures by subcutaneous injection (SC) and oral administration (OA).
Results: For SC method, erupted and unerupted molars could be observed from ICG-NIRF images at a short imaging time (<1 min). ICG-NIRF-II could achieve a better image contrast in unerupted molars at 24 h after ICG injection. The OA could serve as a non-invasive method for ICG delivery; it could also cause the glow-in-dark effect in unerupted molars. For erupted molars, OA can be considered as mouthwash and exhibits outstanding performance for delivery of ICG dye; erupted molar structures could be observed at a short imaging time (<1 min) and low ICG dose (0.05 mg / kg).
Conclusions: Overall, ICG-NIRF with mouthwash could perform in-vivo dental imaging in two NIR wavelengths at a short time and low ICG dose.
Device size has now reached the nanoscale range due to advancements in technology and scaling in the fields of very large-scale integration. The single-electron transistor (SET) is a promising solid-state device that can provide an extension for Moore’s law and is suitable for next-generation nanoelectronics design and application. Due to the Coulomb oscillation properties of the SET in addition to the high gain and ultra-low power consumption of the tunnel field effect transistor (TFET), the implementation of the hybrid SET/TFET will primarily benefit high density (nanoscale), low-power integrated circuits (ICs), and fast switching devices. In this study, we present a hybrid model of a graphene-based single electron transistor [1] with an n-type double-gate graphene nanoribbon TFET structure [2] utilized as an integrator. For simplicity, the TFET is used in the shorted gate configuration by connecting both the front and back gates. Following this, we design a fourth order analog low pass filter using the integrator circuit of SET/TFET. With the implementation in SPICE and Matlab, we analyze the transfer function of our proposed filter from its frequency characteristics (Bode plot). Our findings reveal significant roll-off and, as a consequence, increased filtering functions with low power consumption. This study adds to the realization and implementation of SET/TFET into applications where high frequency contributes to the reliability, performance, and low power required for nanoscale devices and designs.
The making of new nanomaterials for deep tissue imaging is important for clinic applications. In this work, Erbium based metal organic complex nanoparticles is synthesized. They show near-infrared fluorescence (800-1100 nm) when excited by 785 nm light. Deep tissues imaging is demonstrated using a nanoparticle-loaded 2 mL centrifuge tube covered with pig bacon meat tissue. The maximum imaging depth larger than 1.4 cm is achieved. Our work provides a validated procedure to make nanoparticles for near infrared deep tissue imaging.
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