Refine
Document Type
- Article (2)
- Working Paper (1)
Language
- English (3)
Is part of the Bibliography
- yes (3)
Keywords
- Inverted solar cells (1)
- Low band-gap (1)
- Optical modeling (1)
- Organic solar cells (1)
- PCPDTBT (1)
- deliberate ignorance (1)
- emotion regulation (1)
- envy (1)
- experiment (1)
- punishment (1)
Envy is an unpleasant emotion. If individuals anticipate that comparing their payoff with the (potentially higher) payoff of others will make them envious, they may want to actively avoid information about other people’s payoffs. Given the opportunity to reduce another person’s payoff, an individual’s envy may trigger behavior that is detrimental to welfare. In this case, if individuals anticipate that they will react in a welfare-reducing way, they may also avoid information about other people’s payoffs from the outset. We investigated these two hypotheses using three experiments. We found that 13% of our potentially envious subjects avoided information when they did not have the opportunity to reduce another participant’s payoff. Psychological scales do not explain this behavior. We also found that voluntarily uninformed subjects did neither deduct less of the payoff nor less frequently than subjects who could not avoid the information.
We compare standard and inverted bulk heterojunction solar cells composed of PCPDTBT:PC70BM blends. Inverted devices comprising 100 nm thick active layers exhibited short circuit currents of 15 mA/cm(2), 10% larger than in corresponding standard devices. Modeling of the optical field distribution in the different device stacks proved that this enhancement originates from an increased absorption of incident light in the active layer. Internal quantum efficiencies (IQEs) were obtained from the direct comparison of experimentally derived and modeled currents for different layer thicknesses, yielding IQEs of similar to 70% for a layer thickness of 100 nm. Simulations predict a significant increase of the light harvesting efficiency upon increasing the layer thickness to 270 nm. However, a continuous deterioration of the photovoltaic properties with layer thickness was measured for both device architectures, attributed to incomplete charge extraction. On the other hand, our optical modeling suggests that inverted devices based on PCPDTBT should be able to deliver high power conversion efficiencies (PCEs) of more than 7% provided that recombination losses can be reduced.
Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.