They work because certain materials, such as bismuth telluride, generate an electrical potentialdifference within themselves if one part is hotter than another.
它们之所以能起作用是因为一般的材料，比如碲化铋，如果其中一部分比另一部分热，内部就会产生电位差。
3
The electron volt is not a unit of potentialdifference.