新型Sn基磷族层状化合物的结构设计与物理性能研究

The thermoelectric material is a functional material that can convert heat energy and electric energy to each other, and the conversion efficiency is determined by the thermoelectric figure of merit (ZT). At present, the ZT value of most the thermoelectric materials reported have not reached 2, so exploring and designing new high-ZT materials is the frontier and hotspot of the material field. Recently, theoretical and experimental studies have revealed new excellent thermoelectric compounds may exist in the Sn-based phosphorous layered compound ASnPn: on the one hand, the theory predicts that when the carrier concentration of n-type KSnSb is optimized to the order of 10^19 cm^-3, its ZT value along the x-axis can reach 2.2 at 800 K. on the other hand, since both Sn and Pn atoms in ASnPn contain lone pairs of electrons, ASnPn compounds own intrinsically low lattice thermal conductivity. Therefore, this system provides a great platform for exploring new thermoelectric materials. The project aims at the exploration of new Sn-based phosphorous thermoelectric materials. We will take advantage of our enriching experience in new functional layered material design and physical exploration to prepare some new Sn-based phosphorus compounds. Furthermore, the regulation mechanism of the carrier concentration, Fermi level position and lone pair electrons and atomic disordered occupancy will be studied.

热电材料是一种可以实现热能和电能相互转换的功能材料，其转换效率由热电优值ZT决定。目前国际上报道的绝大多数热电材料的ZT值都未达到2，因此探索和设计全新高ZT值热电材料是材料领域的前沿与热点。最近的理论和实验研究均表明Sn基磷族层状化合物ASnPn体系中可能存在性能优异的新热电化合物：一方面理论预测了当n型KSnSb的载流子浓度优化到10^19 cm^-3量级时，沿x轴的ZT值在800 K时可达到2.2；另一方面ASnPn中由于Sn和Pn原子都含有孤对电子，表现出本征低的晶格热导率。因此该体系是很好的探索新热电材料的研究平台。本项目以新型Sn基磷族热电材料的探索为目标，充分利用我们在新型功能层状材料设计和物性探索方面积累的丰富经验，制备出若干新型Sn基磷族化合物，并在该体系中探索出载流子浓度、费米能级位置及孤对电子和原子无序占位的调控机制。

项目执行期间采用固相合成法和放电等离子(sps)烧结工艺制备了ASnPn化合物并研究掺杂和无序对其性能的调控效应；采用一步法和超快脉冲激光处理，使得层状MoS2上同时实现MoS2的纳米晶化和非晶化，以及原子级台阶的修饰；通过超快激光处理的方法作用获得类似荔枝状的RuO2@Ru/RuO2核壳结构;采用固相合成法和超声辅助法制备出PdSe2化合物；采用化学脱嵌法和超声辅助法调控Fe掺杂Co9S8化合物，可以精确调控d带中心的偏移以达到最佳活性；采用一步水热法通过S空位和W掺杂调控Ni3S2化合物，实现自旋态和能带结构的协同调控。研究论文发表在国内外权威刊物上，发表SCI收录论文5篇，其中ESI高被引论文2篇，ESI热点论文1篇。获得了国家发明专利1项。项目执行期间共毕业了9位大学生。建立了较为广泛的国际学术交流与合作关系。