JNCASR finds wave-like heat transport in TlCu5Se3, raising thermoelectric efficiency

1
Researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, reported an unusual wave-like heat transport regime in thallium copper selenide (TlCu5Se3), a copper chalcogenide.
2
The material records a thermoelectric figure of merit (zT) of 1.7, among the highest for pristine ternary chalcogenides, making it a candidate for converting industrial waste heat into electricity.
3
The work, led by Prof. Kanishka Biswas of JNCASR's New Chemistry Unit, was published in Science Advances.

●Thermoelectric conversion turns a temperature difference directly into a voltage — the Seebeck effect, observed by Thomas Johann Seebeck in 1821.
●Efficiency is the dimensionless figure of merit zT = S²σT/κ — high Seebeck coefficient and electrical conductivity, low thermal conductivity.
●TlCu5Se3 recorded a zT of 1.7, among the highest for pristine ternary chalcogenides; it crystallises in a tetragonal, cloverleaf knot-like framework with open channels.
●Heat in crystals is normally carried by particle-like phonons; confined copper-atom disorder here creates strong anharmonicity, so heat moves by wave-like coherence between vibrational modes.
●JNCASR, Jakkur, Bengaluru: set up in 1989 by the Department of Science & Technology for Nehru's birth centenary; deemed university since 2002.
●Superionic conductors get low lattice thermal conductivity from liquid-like mobile ions, but excess ion migration destabilises the crystal — the flaw confined diffusion avoids.
●Led by Prof. Kanishka Biswas (New Chemistry Unit, JNCASR), with Prof. Umesh V. Waghmare on the first-principles calculations.
●Uses cited: waste-heat recovery in power plants, cement, steel, automobiles, data centres and batteries.

upsc

GS Paper 3 > Science & Technology > Developments and their Applications

★UPSC may test what the thermoelectric figure of merit depends on, or which effect underlies direct heat-to-electricity conversion.

Seebeck effect

Generation of a voltage across a material when its two ends are held at different temperatures; the basis of thermoelectric power generation.

Phonon

A quantised lattice vibration that carries heat through a crystalline solid.

•zT = S²σT/κ — a high Seebeck coefficient and electrical conductivity with low thermal conductivity.
•JNCASR was set up in 1989 under the Department of Science & Technology and is located at Jakkur, Bengaluru.
•TlCu5Se3 reported a zT of 1.7.

•Do not confuse the Seebeck effect (temperature difference produces voltage) with the Peltier effect (current produces a temperature difference) — the pair is a standard prelims trap.

Question 1 of 2Score: 0/0

Conceptual

Current Affairs Pulse