 bismuth telluride by 2T3, and its alloys have been widely used as materials for thermoelectric refrigeration and thermoelectric generators. These materials exhibit a high dimensionless figure of merit, ZT, which increases with temperature until it reaches a maximum value, then begins to decrease. This behavior is attributed to the presence of two types of charge carriers, majority and minority carriers, which can lead to increased efficiency at higher temperatures. However, at higher temperatures, the presence of minority carriers leads to a decrease in ZT. Additionally, the presence of tellurium vapors can cause chemical decomposition, leading to a decrease in performance. To optimize performance at higher temperatures, compositions of by 2T3 based thermal elements should be adjusted to reduce the amount of tellurium present. This article was authored by H. Julian Goldsmith.