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The n -type PbTe still maintains relatively low thermoelectric performance compared with its p -type counterpart. Thus, to promote its performance in n -type PbTe, we conduct successive strategies that firstly suppressing the lattice thermal conductivity (κ lat) through alloying with ternary compound AgSbSe 2 , and then optimizing carrier density with Sb, Bi or I doping. In AgSbSe 2 -alloyed PbTe samples, the κ lat can be evidently reduced, and the minimum κ lat decreases from ∼1.1 Wm−1K−1 in undoped PbTe to ∼0.8 Wm−1K−1 in PbTe–5%AgSbSe 2. Based on PbTe–5%AgSbSe 2 matrix, several dopants (Sb, Bi or I) are used to optimize its carrier density, and found that I element is verified to be the most effective dopant to enhance its electrical transport properties. In I-doped PbTe–5%AgSbSe 2 samples, the carrier density raises from ∼2.49 × 1016 cm−3 in PbTe–5%AgSbSe 2 to ∼1.15 × 1019 cm−3 in PbTe 0.992 I 0.008 -5%AgSbSe 2 , which contributes to the maximum power factor ∼14.8 μWcm−1K−2. Combining the reduced lattice thermal conductivity and improved power factor, the maximum ZT max and average ZT ave values in PbTe 0.992 I 0.008 -5%AgSbSe 2 are boosted to ∼1.0 at 723 K and ∼0.77 at 300–823 K, respectively. This work points out a valid avenue to improve thermoelectric transport property in n -type PbTe with separately successive strategies to adjust its thermal and electrical performance. • κ min ∼0.8 Wm−1K−1 was achieved in n -type PbTe through introducing AgSbSe 2. • PF max of n -type PbTe was significantly enhanced from ∼3.4 μWcm−1K−2 to ∼14.8 μWcm−1K−2 by I doping. • ZT max of n -type PbTe was enhanced from ∼0.45 to ∼1.00. [ABSTRACT FROM AUTHOR]

PbTe-based thermoelectric materials are considered to be a medium-temperature thermoelectric candidates and the high-performance n -type PbTe is urgently to be developed to match its p -type counterpart on account of practical application. Herein, we firstly optimized the carrier density of n -type PbTe through Sb doping, and obtained a maximum ZT value of ∼1.0. Then, based on the optimized carrier density, we introduced ternary compounds AgSb(Se, Te) 2 to suppress the lattice thermal conductivity. Minimum lattice thermal conductivity of n -type PbTe was reduced as low as ∼0.53 W m−1K−1 and ∼0.62 Wm−1K−1 through introducing AgSbSe 2 and AgSbTe 2 , respectively. Combining the maintained electrical properties with suppressed thermal conductivity, maximum ZT values ∼1.2 and ∼1.3 were obtained in PbTe+2%AgSbSe 2 and PbTe+2%AgSbTe 2 , respectively. This work provides an effective strategy of synergistically balancing charge and phonon transports in n -type PbTe with ternary AgSb(Se, Te) 2 compounds. • κ min of n -type PbTe was reduced to ∼ (0.53–0.62) Wm−1K−1 through introducing AgSb(Se, Te) 2. • Power factor ∼20.0 μWcm−1K−2 was realized in n -type PbTe through maintaining carrier mobility. • ZT max of n -type PbTe was enhanced from ∼1.0 to ∼ (1.17–1.25). [ABSTRACT FROM AUTHOR]