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Photoelectric effect
The photoelectric effect is the emission of electrons from matter upon the absorption of electromagnetic radiation, such as ultraviolet radiation or x-rays. Upon exposing a metallic surface to electromagnetic radiation that is above the threshold frequency or threshold wavelength (which is specific to the type of surface and material), the photons are absorbed and current is produced. No electrons are emitted for radiation with a frequency below that of the threshold, as the electrons are unable to gain sufficient energy to overcome the electrostatic barrier presented by the termination of the crystalline surface.
By conservation of energy, the energy of the photon is absorbed by the electron and, if sufficient, the electron can escape from the material with a finite kinetic energy. A single photon can only eject a single electron, as the energy of one photon may only be absorbed by one electron. The electrons that are emitted are often termed photoelectrons.
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Matter & Energy News
October 29, 2025
Oct. 29, 2025 — Tohoku University researchers have found a way to make quantum sensors more sensitive by connecting superconducting qubits in optimized network patterns. These networks amplify faint signals possibly left by dark matter. The approach outperformed ...
Oct. 25, 2025 — A UCLA-led team has achieved the sharpest-ever view of a distant star’s disk using a groundbreaking photonic lantern device on a single telescope—no multi-telescope array required. This technology splits incoming starlight into multiple ...
Oct. 25, 2025 — Researchers propose that hydrogen gas from the early Universe emitted detectable radio waves influenced by dark matter. Studying these signals, especially from the Moon’s radio-quiet environment, could reveal how dark matter clumped together ...
Oct. 24, 2025 — A team of researchers has designed a theoretical model for a topological quantum battery capable of long-distance energy transfer and immunity to dissipation. By exploiting topological properties in photonic waveguides, they showed that energy loss ...
Oct. 23, 2025 — Scientists have developed a chromium-molybdenum-silicon alloy that withstands extreme heat while remaining ductile and oxidation-resistant. It could replace nickel-based superalloys, which are limited to about 1,100°C. The new material might make ...
Oct. 21, 2025 — Researchers have found that 2D materials can self-form microscopic cavities that trap light and electrons, altering their quantum behavior. With a miniaturized terahertz spectroscope, the team observed standing light-matter waves without needing ...
Oct. 20, 2025 — A new light-driven cancer therapy uses LEDs and tin nanoflakes to kill tumors safely and affordably. Developed by teams in Texas and Portugal, it eliminates up to 92% of skin cancer cells without ...
Oct. 19, 2025 — Researchers from NTNU and EPFL have unveiled a compact, low-cost laser that outperforms current models in speed, control, and precision. Built using microchip technology, it can be mass-produced for use in everything from Lidar navigation to gas ...
Oct. 18, 2025 — A collaboration between the University of Michigan and AFRL has resulted in 3D-printed metamaterials that can block vibrations using complex geometries. Inspired by nature and theoretical physics, these “kagome tubes” demonstrate how geometry ...
Oct. 17, 2025 — Researchers discovered how to stabilize a high-performance sodium compound, giving sodium-based solid-state batteries the power and stability they’ve long lacked. The new material conducts ions far ...
Oct. 11, 2025 — A team of engineers at North Carolina State University has designed a polymer “Chinese lantern” that can rapidly snap into multiple stable 3D shapes—including a lantern, a spinning top, and more—by compression or twisting. By adding a ...
Oct. 11, 2025 — Scientists have developed an ultra-thin, paper-like LED that emits a warm, sunlike glow, promising to revolutionize how we light up our homes, devices, and workplaces. By engineering a balance of red, yellow-green, and blue quantum dots, the ...
Latest Headlines
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Oct. 29, 2025 — A University of Tokyo team has turned organic molecules into nanodiamonds using electron beams, overturning decades of assumptions about beam damage. Their discovery could transform materials science ...
Oct. 29, 2025 — Rice University researchers have captured the temperature profile of quark-gluon plasma, the ultra-hot state of matter from the dawn of the universe. ...
Oct. 26, 2025 — MIT researchers have devised a new molecular technique that lets electrons probe inside atomic nuclei, replacing massive particle accelerators with a tabletop setup. By studying radium monofluoride, ...
Oct. 24, 2025 — Researchers in Konstanz discovered a way to manipulate materials with light by exciting magnon pairs, reshaping their magnetic “fingerprint.” This allows non-thermal control of magnetic states ...
Oct. 23, 2025 — Chalmers researchers have developed a simple, light-based platform to study the mysterious “invisible glue” that binds materials at the nanoscale. Gold flakes floating in salt water reveal how ...
Oct. 23, 2025 — Researchers suggest that dark matter might subtly color light red or blue as it passes through, revealing traces of its existence. Using a network-like model of particle connections, they argue that ...
Oct. 22, 2025 — Under the sea, green algae have evolved a clever way to handle too much sunlight. Scientists found that a special pigment called siphonein acts like a natural sun shield, protecting the algae’s ...
Oct. 21, 2025 — Physicists have uncovered the fascinating world of “rotating crystals” — solids made of spinning particles that behave in strange, almost ...
Oct. 18, 2025 — Researchers have unveiled a new model for the universe’s birth that replaces cosmic inflation with gravitational waves as the driving force behind creation. Their simulations show that gravity and ...
Oct. 16, 2025 — Auburn scientists have designed new materials that manipulate free electrons to unlock groundbreaking applications. These “Surface Immobilized Electrides” could power future quantum computers or ...