Results 141 to 150 of about 4,027,935 (330)

Extended Probabilities: Mathematical Foundations

open access: yes, 2009
There are important problems in physics related to the concept of probability. One of these problems is related to negative probabilities used in physics from 1930s. In spite of many demonstrations of usefulness of negative probabilities, physicists looked at them with suspicion trying to avoid this new concept in their theories. The main question that
openaire   +2 more sources

Traps, Tail States and Their Consequences on the Open‐circuit Voltage in Organic Solar Cells

open access: yesAdvanced Energy Materials, EarlyView.
It is found that the light‐intensity dependent low‐temperature roll‐off of open‐circuit voltage in organic solar cells is explained by the intrinsic disorder in these devices, which can be either described by the full Gaussian density of states or approximated by a two‐level system, which allows for a more intuitive interpretation.
Tobias Krebs   +2 more
wiley   +1 more source

Determining Exciton Diffusion Length in Organic Semiconductors: Unifying Macro‐ and Microscopic Perspectives

open access: yesAdvanced Energy Materials, EarlyView.
Exciton diffusion length in organic semiconductor films is determined from encounter/annihilation rates. Non‐normalized exciton densities and proper intrinsic lifetime reference avoid over‐parametrization of the fits. Monte Carlo Simulation of individual molecule‐to‐molecule hops reproduce these results (②) when matching lattice constant and hoping ...
Wenchao Yang   +12 more
wiley   +1 more source

Transport Resistance Dominates the Fill Factor Losses in Record Organic Solar Cells

open access: yesAdvanced Energy Materials, EarlyView.
Organic photovoltaics are a promising solar cell technology, but even the record devices with 20% efficiency have significant fill factor losses due to low active layer conductivities. In this Perspective, the authors describe the origin of these losses, discuss experimental methods for their quantification, and explain how to minimize them to optimize
Chen Wang   +6 more
wiley   +1 more source

The Value of Device Characterization for the Optimization of Organic Solar Cells

open access: yesAdvanced Energy Materials, EarlyView.
Using the example of organic photovoltaics (OPV), this study examines whether and when additional measurements can be helpful in process optimization. A virtual laboratory based on real solar cells serves as a benchmark function to compare two different approaches for process optimization, namely black‐box optimization (black circle) and model‐based ...
Leonard Christen   +4 more
wiley   +1 more source

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