We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5 μm thin Si absorber layers were prepared by diode laser crystallization of amorphous Si deposited by electron beam evaporation on glass. On these absorber layers, we studied the effect of SiOx and Al2O3 terminated Si surfaces. The short circuit density and power conversion efficiency (PCE) of the mc-Si/Al2O3/PEDOT:PSS solar cell increase from 20.6 to 25.4 mA/cm2 and from 7.3% to 10.3%, respectively, as compared to the mc-Si/SiOx/PEDOT:PSS cell. Al2O3 lowers the interface recombination and improves the adhesion of the polymer film on the hydrophobic mc-Si thin film. Open circuit voltages up to 604 mV were reached. This study demonstrates the highest PCE so far of a hybrid solar cell with a planar thin film Si absorber.

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In combustion and gasification diagnostics, the knowledge of temperature distribution and gas component concentration is crucial in order to understand or optimize such processes. In this study, we compare ultra‐broadband two‐beam femtosecond/picosecond coherent anti‐Stokes Raman scattering (fs/ps CARS) with spontaneous Raman scattering to retrieve temperature and concentration information. We show that two‐beam fs/ps CARS can be effectively used for concentration measurements down to 0.5% CO in gas mixtures of CO2 and N2. With two‐beam fs/ps CARS, thermometry from ~200°C to ~800°C based on CARS spectra of CO2 or H2 is shown. With spontaneous Raman scattering, concentration determination is well performed in gas mixtures of H2, N2, and CO2 with H2 content ranging from 16% to 0.5% at room temperature and from 16% to 7% H2 at ~900°C. Besides, thermometry in gas mixtures of N2 and CO2 from ~200°C to ~600°C based on spontaneous Raman scattering is also shown in this study.