Band Gap
Band Gap - Related Videos
02:35
Band Theory
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2020
When two or more atoms come together to form a molecule, their atomic orbitals combine and molecular orbitals of distinct energies result. In a solid, there are a large number of atoms, and therefore a large number of atomic orbitals that may be combined into molecular orbitals. These groups of molecular orbitals are so closely placed together to form continuous regions of energies, known as the bands. The energy difference between these bands is known as the band gap. Conductor, Semiconductor,...
08:12
Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
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Cited by 2 •
2017
Here, we present a protocol for the synthesis of CH3NH3I and CH3NH3Br precursors and the subsequent formation of pinhole-free, continuous CH3NH3PbI3-xBrx thin films for the application in high efficiency solar cells and other optoelectronic devices.
01:37
Gap Junctions
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2026
Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between neighboring cells in animals, connecting the cytoplasm between the two, and allowing for the exchange of molecules and ions. They are found in a wide range of invertebrate and vertebrate species, mediate numerous functions including cell differentiation and development, and are associated with numerous human diseases, including cardiac and...
01:27
Gap Junctions
0 Views •
2023
The cytoplasm of adjacent animal cells can exchange small molecules, ions, and secondary messengers via the communication channels which form the gap junctions. These junctions comprise a few hundred to thousands of molecular channels, each made of two halves, called the connexon hemichannel. A connexon is a hexamer of six transmembrane connexin proteins, which assemble radially, thus forming a pore or channel in the center. One connexon hemichannel docks with a corresponding connexon on the...
01:01
Energy Bands in Solids
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2024
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels. Band Formation: When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
FAQs
The key event is promotion of an electron into the conduction band. This leaves a positively charged hole in the valence band, so the material contains separated charge carriers rather than only an absorbed photon. Photon excitation can initiate this change when its energy reaches the gap, while thermal excitation can provide the necessary energy without light. Their presence explains why band-gap behavior matters for charge transport and chemical reactivity.
Light absorption depends on whether incoming photons can supply enough energy to cross the gap. Consequently, a material may absorb some parts of visible or other incident light while not responding to photons below the required energy. The wavelengths that remain absorbed or transmitted contribute to observed optical color, making band-gap analysis useful for interpreting color differences among semiconductor materials.
Electrical conductivity and chemical reactivity both reflect how readily excitation produces charge carriers. When electrons reach the conduction band, they can contribute to charge transport, while holes left behind provide the corresponding positive charge. In chemical systems, this electron-hole pair links electronic structure to reactions driven by light or thermal energy, so band gap is not merely an optical property.
In chemistry, band-gap measurements connect a material’s electronic structure with observable optical and electrical behavior. Comparing the measured gap among semiconductor materials can help researchers interpret differences in color, conductivity, and reactivity. That information supports selection or design of materials for energy conversion, sensing, light emission, and environmental photocatalysis rather than treating performance as an isolated property.
Solar cells rely on band-gap behavior to determine how materials respond to incoming light and generate charge carriers. Light-emitting devices use the same relationship between energy and electronic transitions to produce light, while sensors exploit changes in light or electrical response. Thus, band-gap information helps match semiconductor materials to the function required in each device.
For photocatalysts, the band gap indicates whether light or thermal energy can promote electrons and leave holes available for reactive processes. This makes the property relevant to materials designed for energy conversion and environmental applications. Chemical researchers can therefore use band-gap information alongside observed reactivity to evaluate semiconductor candidates for processes where illumination and charge generation are important.