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This study attempts to enhance broadband absorption in advanced plasmonic circular nanostructures (PCN). Experimental results indicate that the concentric circular metallic gratings can enhance broadband optical absorption, due to the structure geometry and the excitation of surface plasmon mode. The interaction between plasmonic enhancement and the absorption characteristics of the organic materials (P3HT:PCBM and PEDOT:PSS) are also examined. According to those results, the organic material's overall optical absorption can be significantly enhanced by up to~51% over that of a planar device. Additionally, organic materials are enhanced to a maximum of 65% for PCN grating pitch = 800 nm. As a result of the PCN's enhancement in optical absorption, incorporation of the PCN into P3HT:PCBM-based organic solar cells (OSCs) significantly improved the performance of the solar cells: short-circuit current increased from 10.125 to 12.249 and power conversion efficiency from 3.2% to 4.99%. Furthermore, optimizing the OSCs architectures further improves the performance of the absorption and PCE enhancement.

A photo-excited organic layer on a metal thin film with a corrugated substrate was used to generate surface plasmon grating coupled emissions (SPGCEs). Directional emissions corresponded to the resonant condition of surface plasmon modes on the Au/air interface. In experimental comparisons of the effects of different pitch sizes on the plasmonic band-gap, the obtained SPGCEs were highly directional, with intensity increases as large as 10.38-fold. The FWHM emission spectrum was less than 70 nm. This method is easily applicable to detecting refractive index changes by using SP-coupled fluorophores in which wavelength emissions vary by viewing angle. The measurements and calculations in this study confirmed that the color wavelength of the SPGCE changed from 545.3 nm to 615.4 nm at certain viewing angles, while the concentration of contacting glucose increased from 10 to 40 wt%, which corresponded to a refractive index increase from 1.3484 to 1.3968. The organic plasmon-emitting diode exhibits a wider linearity range and a resolution of the experimental is 1.056 × 10−3 RIU. The sensitivity of the detection limit for naked eye of the experimental is 0.6 wt%. At a certain viewing angle, a large spectral shift is clearly distinguishable by the naked eye unaided by optoelectronic devices. These experimental results confirm the potential applications of the organic plasmon-emitting diodes in a low-cost, integrated, and disposable refractive-index sensor.

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A CMOS current-mode exponential circuit is designed by plugging candidate circuits into a Taylor's approximation circuit to make a multiple-segment circuit. The selection of candidate circuits is dependent on a large linearity range in each segment. The proposed range-segmented circuit is different from all segments constructed only by quadratic circuits or only by linear circuits. The proposed circuit was simulated using UMC 0.18 µ m CMOS technology. The output linearity of the circuit is 56.7 dB for gain error less than 0.5 dB, and the-3 dB bandwidth of the circuit is between 69 and 150 MHz for input range from-63 to 198 µ A.