Plasmonic Forward Scattering Effect in Organic Solar Cells: A Powerful Optical Engineering Method
In this report, plasmonic effects in organic photovoltaic cells (OPVs) are systematically analyzed using size-controlled silver nanoparticles (AgNPs, diameter: 10 ~ 100 nm), which were incorporated into the anodic buffer layer, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The optical properties of AgNPs tuned by size considerably influence the performance levels of devices. The power conversion efficiency (PCE) was increased from 6.4% to 7.6% in poly[N-9-hepta-decanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)] (PCDTBT):[6,6]-phenyl C71-butyric acid methyl ester (PC70BM) based-OPVs and from 7.9% to 8.6% in polythieno[3,4-b]thiophene/benzodithiophene (PTB7):PC70BM based-OPVs upon embedding the AgNPs. The external quantum efficiency (EQE) was significantly enhanced by the absorption enhancement due to the plasmonic scattering effect. Finally, we verified the origin of the size-dependent plasmonic forwarding scattering effect of the AgNPs by visualizing the scattering field with near-field optical microscopy (NSOM) and through analytic optical simulations. [1]
Optical engineering with Fibonacci dielectric multilayers
We study the resonant transmission of light through Fibonacci dielectric multilayers (FDM). Making use of a transfer matrix renormalization technique [E. Maciá and F. Domı́nguez-Adame, Phys. Rev. Lett. 76, 2957 (1996)] we obtain closed analytical expressions for the transmission coefficient under arbitrary incidence angle conditions. We analyze the relationship between the resonant wavelengths and the quasiperiodic structure of the substrate, suggesting the potential use of arrays containing FDMs of different sizes in the design of optical microcavities [2]
Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale
Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin‐film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures. [3]
Performance Analysis of Free Space Optical Communication Link Using Different Modulation and Wavelength
In this paper different modulation formats NRZ and RZ and different wavelengths 1550 nm and 1310 nm and two photodiodes APD and PIN has been investigated on free space optical communication link. The value of Q has been observed in all the cases in different eye diagrams. It is clear from the observations that the Q value is highest when we use wavelength of 1550 nm, NRZ modulation format and APD photodiode. On the other hand it is lowest when the same wavelength is used with RZ modulation format along with PIN photodiodes. [4]
Optical Characteristics of CdO Nanostructure
The Cadmium Oxide (CdO) transparent nanostructure semiconducting film is deposited on glass substrates by spray pyrolysis method at 250ºC. The structural and optical properties of the growth films are presented. The crystalline structure was studied by X-ray diffraction. The direct band gap of CdO nanofilm was found to be 3.4eV, comparing with that of the bulk CdO. [5]
Reference
[1] Baek, S.W., Noh, J., Lee, C.H., Kim, B., Seo, M.K. and Lee, J.Y., 2013. Plasmonic forward scattering effect in organic solar cells: a powerful optical engineering method. Scientific reports, 3, p.1726.
[2] Maciá, E., 1998. Optical engineering with Fibonacci dielectric multilayers. Applied physics letters, 73(23), pp.3330-3332.
[3] Luo, G., Ren, X., Zhang, S., Wu, H., Choy, W.C., He, Z. and Cao, Y., 2016. Recent advances in organic photovoltaics: Device structure and optical engineering optimization on the nanoscale. Small, 12(12), pp.1547-1571.
[4] Kaur, H. and Soni, G. (2015) “Performance Analysis of Free Space Optical Communication Link Using Different Modulation and Wavelength”, Journal of Scientific Research and Reports, 6(3), pp. 201-209. doi: 10.9734/JSRR/2015/15503.
[5] Natik Naje, A. (2013) “Optical Characteristics of CdO Nanostructure”, Physical Science International Journal, 3(4), pp. 472-478. Available at: https://www.journalpsij.com/index.php/PSIJ/article/view/23099 (Accessed: 26November2020).
