Ultra-low thermal conductivity, high thermoelectric figures of merit and high photocatalytic activity of monolayer Ag(2-)Cu S (x = 0, 1, 2)

High mobility and excellent thermoelectric performance monolayer ZnX2Z4 (X = In, Al, Ga; Z = S, Se, Te) materials

“…4(a-1). The results indicated that the Seebeck coefficient ( S ) of these three monolayers possesses peak values of 874 μV K −1 , 140 μV K −1 , and 397 μV K −1 at 300 K, respectively, which are higher than or comparable to those of Ba 2 AgSb (∼323.6 μV K −1 ), 46 α-Te (242.9–700 μV K −1 ) 47 and Cu 2 S (250–300 μV K −1 ). 48 Notably, the S values of β 2 -ZnAl 2 Te 4 are much larger than that of β 2 -ZnGa 2 Te 4 and β 2 -ZnIn 2 Te 4 , which can be attributed to the fact that β 2 -ZnAl 2 Te 4 has a lower band gap producing a lower carrier concentration.…”

“…4(a-1). The results indicated that the Seebeck coefficient (S) of these three monolayers possesses peak values of 874 mV K À1 , 140 mV K À1 , and 397 mV K À1 at 300 K, respectively, which are higher than or comparable to those of Ba 2 AgSb (B323.6 mV K À1 ), 46 a-Te (242.9-700 mV K À1 ) 47 and Cu 2 S (250-300 mV K À1 ). 48 The relationship between the Seebeck coefficient and carrier concentration can be derived from the expression of the Seebeck coefficient: 49…”