Bang-Zhou Tian,Yi-Yan Liao,Fang Xu,Xiao-Ling Qiu,Fu-Jie Zhang,Ran Ang
Interfacial modulation has been considered an effective strategy to enhance the thermoelectric (TE) performance by decoupling thermal and electrical parameters. However, inappropriate interfacial heterojunctions can significantly deteriorate electrical transport while enhancing phonon scattering, which causes no substantial improvement in TE performance. Herein, we introduce two-dimensional graphene or MXene into the Mg3.2Sb0.5Bi1.49Te0.01 matrix by ball mixing combined with rapid sintering to modify the composition and structure at the interface. The differences in morphology, size and distribution of interfacial graphene and MXene lead to distinct results which show that incorporated graphene flakes with larger size hinder the carrier transport, while the homogeneously dispersed tiny MXene provides improved carrier channels and boosts the mobility. On the other hand, such uniformly diffused heterogeneous MXene structures create stronger scattering on phonons compared to enriched graphene phases, resulting in a low lattice thermal conductivity of ∼0.66 W m−1 K−1 and enhanced zT of ∼1.0 at 513 K in Mg3.2Sb0.5Bi1.49Te0.01-0.6 wt% MXene with good component stability in air. This work highlights the importance of size, concentration, and distribution in the interfacial modulation strategy, demonstrating an effective method for developing high TE performance Mg3(Sb, Bi)2-based near-room-temperature materials.
Zijun Yi,Bo Xiao,Xin Li,Yubo Luo,Qinghui Jiang,Junyou Yang
The severe non-radiative recombination loss caused by SnO 2 /perovskite interface defects greatly hinders the further improvement of the performance and stability of flexible perovskite solar cells (PSCs). Herein, a series of halides KM (M = F, Cl, Br, I) were inserted as interface layers to modulate the SnO 2 /perovskite interface. Both experimental and theoretical calculation demonstrated that F − exhibited stronger interface coupling effect between the SnO 2 and perovskite than other halide ions (Cl − , Br − , I − ). The F − had unique effects in effectively depressing SnO 2 /perovskite interface defects ascribed to the simultaneous formation of Sn F bonds and hydrogen bonds , resulting in reduced non-radiative recombination and improved interfacial contact. In consequence, the champion KF-modified flexible and rigid PSCs delivered outstanding PCE of 18.16 % and 21.36 %, accompanied by the enhanced V OC of 1.14 V and 1.16 V, respectively. Meanwhile, the stability of flexible PSCs was significantly ameliorated after KF modification, and about 84 % of the original efficiency could be retained even after 3000 bending cycles. This work provides a facile and efficient strategy for interface modulation to achieve high-performance and stable flexible PSCs.
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