Organic semiconductor

About: Organic semiconductor is a research topic. Over the lifetime, 15905 publications have been published within this topic receiving 533881 citations.

Morphology control strategies for solution-processed organic semiconductor thin films

Abstract: While the chemical structure of organic semiconductors has an obvious effect on their proclivity for charge transport, the ways with which they are processed have a dramatic effect on the performance of plastic electronics devices incorporating them. In some cases, morphological defects and misalignment of crystalline grains can completely obscure the materials' intrinsic charge transport properties. Although some deposition methods, especially vapor-phase ones, can produce single crystals and thus avoid some of these problems, it is desirable to gain a fundamental understanding of how to improve charge transport when using solution-phase deposition techniques. In this review, we present both a survey of solution-based processing techniques for plastic electronics relevant on both the commercial and research scale and a set of strategies to control thin film morphology towards enhancing their electronic transport properties.

Comparing organic to inorganic photovoltaic cells: Theory, experiment, and simulation

Abstract: Charge carriers are photogenerated with very different spatial distributions in conventional inorganic photovoltaic (IPV) cells and in organic photovoltaic (OPV or excitonic) cells. This leads to a fundamental, and often overlooked, mechanistic difference between them. Carriers are generated primarily at the exciton-dissociating heterointerface in OPV cells, resulting in the production of electrons in one phase and holes in the other—the two carrier types are thus already separated across the interface upon photogeneration in OPV cells, giving rise to a powerful chemical potential energy gradient ∇μhv that promotes the photovoltaic effect. This occurs also in high-surface-area OPV cells, although their description is more complex. In contrast, both carrier types are photogenerated together throughout the bulk in IPV cells: ∇μhv then drives both electrons and holes in the same direction through the same phase; efficient carrier separation therefore requires a built-in equilibrium electrical potential energ...

Bimolecular recombination in polymer/fullerene bulk heterojunction solar cells

Abstract: Bimolecular recombination in organic semiconductors is known to follow the Langevin expression, i.e., the rate of recombination depends on the sum of the mobilities of both carriers. We show that this does not hold for polymer/fullerene bulk heterojunction solar cells. The voltage dependence of the photocurrent reveals that the recombination rate in these blends is determined by the slowest charge carrier only, as a consequence of the confinement of both types of carriers to two different phases.

Structural order in conjugated oligothiophenes and its implications on opto-electronic devices

Abstract: Over the last ten years, conjugated oligothiophenes have emerged as one of the largest families of organic semiconductors with potential applications in electronics devices. Thin film transistors (TFTs), photovoltaic solar cells, light-emitting diodes (LEDs), light modulators, photochromic switches and laser microcavities are some examples of devices that have been fabricated with oligothiophenes as the active materials. The key advantage of well-defined oligomers over their parent polymers is the high degree of molecular and crystalline ordering they can achieve. Polycrystalline and highly oriented thin films can be easily prepared from solution or by vacuum deposition. In many cases it has even been possible to grow single crystals and elucidate their X-ray structure. The aim of this review is to describe the structure of oligothiophene crystals and thin films and to explore its implications on the performances of various electronic devices.

Three‐layered organic solar cell with a photoactive interlayer of codeposited pigments

Abstract: Three‐layered organic solar cell with an interlayer of codeposited pigments of n‐type perylene tetracarboxylic derivative (Me‐PTC) and p‐type metal‐free phthalocyanine (H2Pc) in between the respective pigment layers, was fabricated. Two times larger photocurrent compared to the double‐layered cell without an interlayer was obtained due to the efficient carrier photogeneration in a codeposited layer. The power conversion efficiency reached 0.7% under the intense white light of 100 mW cm−2.