Realizing ultrahigh ZT value and efficiency of the Bi2Te3 thermoelectric module by periodic heating

•Thermal and electrical contact resistances of 3.65 × 10−5 m2⋅K⋅W−1 and 1.18 × 10−10 Ω⋅m2⋅K are obtained.•Time average ZT value and effective efficiency are greatly improved by periodic heating.•Efficiency of 5.75% and ZT value of 1.12 are achieved under the optimal transient heat source.•Smaller leg height, larger leg area, more TE couples, and lower thermal conductivity are suggested.