Large thermoelectric figure of merit in hexagonal phase of 2D selenium and tellurium

• Published in: International journal of quantum chemistry 2020-09, Vol.120 (17), p.n/a
• Main Authors: Ramírez‐Montes, Luz, López‐Pérez, William, González‐Hernández, Rafael, Pinilla, Carlos
• Format: Article
• Language: English
• Subjects: Chemistry; density functional theory; Elastic properties; Figure of merit; hexagonal 2D materials; Hexagonal phase; Mathematical analysis; Optoelectronics; Physical chemistry; Quantum physics; selenene and tellurene; Selenium; Tellurium; thermoelectric figure of merit; Thermoelectric materials
• ISSN: 0020-7608; 1097-461X
• DOI: 10.1002/qua.26267

We found a large thermoelectric figure of merit in the hexagonal phase of 2D selenium and tellurium from first‐principles calculations. The hexagonal phase (α) is obtained from three atomic layers truncated along the [001] direction of trigonal Te and Se bulk in the equilibrium structure. We found the α‐Se structure dynamically stable. The calculated electronic structures of α‐Se and α‐Te show interesting semiconductor character for both electronic and optoelectronic applications. Furthermore, the obtained elastic properties show that hexagonal tellurene is a softer material than selenene. The thermoelectric figure of merit for hexagonal 2D phase (∼1.0) is larger than those reported for the tetragonal 2D phase (∼0.75) of selenium and tellurium. Additionally, the computed electrical and phonon transport parameters indicate that selenene and tellurene are promising thermoelectric materials; both offer an alternative to recovering residual heat and transforming it into electricity. Thermoelectric materials, which allow direct conversion between thermal and electrical energy, are useful in alternative renewable energy technologies. The efficiency of energy conversion of thermoelectric materials requires a large figure of merit and low thermal conductivity. For this, it is necessary to have a structure of massive atoms, such as selenium and tellurium.