We investigate the competitive effects of the merger between Delta Air Lines and Northwest Airlines (2009) in the domestic U.S. airline industry. Applying fixed effects regression models we find that the transaction led to short term price increases of about 11 percent on overlapping routes and about 10 percent on routes which experienced a merger-induced switch of the operating carrier. Over a...

In lead halide perovskite solar cells, there is at least one recycling event of electron-hole pair to photon to electron-hole pair at open circuit under solar illumination. This can lead to a significant reduction in the external photoluminescence yield from the internal yield. Here we show that, for an internal yield of 70%, we measure external yields as low as 15% in planar films, where light...

Ionic liquids and poly(ionic liquid)s act as bulk and/or passivation agents when used additives in methylammonium-free lead perovskites, leading to devices showing enhanced power conversion efficiencies, reduced hysteresis improved stability.

Experimental results with second-harmonic 460 nm-wavelength emission are presented. A profound analytical description of the intra-cavity beam shaping properties of the resonator based on the ABCD-law provides an effective design tool for the construction of appropriate resonator setups. Also described is the layer design of the optically pumped laser chip in which the fundamental radiation is ...

Hole extraction in organic photovoltaic cells (OPVs) can be modulated by a surface-enriched layer formed on top of the conducting polymer-based hole extraction layer (HEL). This tunes the surface work function of the HEL to better align with the ionization potential of the polymeric photoactive layer. Results show noticeable improvement in device power conversion efficiencies (PCEs) in OPVs. We...

This study investigates novel deposition techniques for the preparation of TiO2 electrodes for use in flexible dye-sensitized solar cells. These proposed new methods, namely pre-dye-coating and codeposition ultrasonic spraying, eliminate the conventional need for time-consuming processes such as dye soaking and high-temperature sintering. Power conversion efficiencies of over 4.0% were achieved...

Microcrystalline silicon solar cells with AM 1.5 conversion efficiency above 5 % have been deposited at deposition rates in excess of 10 Å/s. This is achieved by VHF-GD at an excitation frequency of 130 MHz. By increasing the plasma power at a dilution ratio of 7.5 % silane/(silane+hydrogen) there first appears a morphological transition from a-Si:H to μc-Si:H and then an increase in deposition...

We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficie...

Two diacetylide-triphenylamine hole-transport materials (HTM) with varying redox potential have been applied in planar junction TiO2-[CH3NH3]PbI3-xClx solar cells leading to high power-conversion efficiencies up to 8.8%. More positive oxidation potential of the HTM gives higher VOC and lower JSC illustrating the role of matching energy levels, however both HTMs gave efficient cells despite a di...