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Thermoelectrics (TEs) are a class of materials capable of converting heat into electricity in the solid state. Their widespread application is limited by the low efficiency (≈ 5 %) for commercial modules in applications such as waste heat recovery and refrigeration. Half-Heusler (hH) TE intermetallic alloys have good electrical properties that are easily tuned by doping but are limited in commercial deployment due to high thermal conductivity (TC). This limits the achievable thermal gradient across a TE module, reducing the efficiency. One method to improve hH alloy performance is to decrease the lattice contribution to the TC through solid-solution alloying.Combinatorial synthesis approaches have the advantage of rapid sample fabrication and characterization over a wide range of material compositions. This approach can provide insights into materials systems that could be missed using conventional synthesis approaches. Several publications reported p-type NbFeSb hH alloys can accommodate off-stoichiometry, which could positively impact the TE properties similar to TC decrease observed via Ta-alloying. Combinatorial thin film co-sputter synthesis of hH alloy (Ta0.40Nb0.40Ti0.20)-Fe-Sb composition spread libraries coupled with high throughput (HiTp) characterization is utilized to produce maps of the composition-structure-property relationships as a function of Fe- and Sb-content in this system for the first time. Continuous spread composition gradient and homogeneous discrete cosputtered combinatorial thin film synthesis methodologies are leveraged to investigate the hH stability region and TE performance in (Ta0.40Nb0.40Ti0.20)-Fe-Sb. Combinatorial thin film characterization requires specialized custom or commercial instrumentation capable of scanning across samples. Established HiTp tools were utilized to characterize the crystal structure, electrical transport properties (Seebeck coefficient and electrical resistivity), and chemical composition of the films. A scanning thin film TC measurement instrument was not available prior to this dissertation. Without this ability, the dimensionless TE figure-of-merit zT cannot be calculated. To address this need, a custom, automated Frequency Domain Thermoreflectance (FDTR) instrument was designed and constructed. FDTR TC measurements are presented on single-phase F43m off stoichiometric discrete combinatorial hH (Ta0.40Nb0.40 Ti0.20)-Fe-Sb for the first time. Maximum zT values at 296 K are calculated to be 0.076 for compositions (Nb0.412 Ta0.327 Ti0.261) 28.5Fe40.3Sb31.2 and (Nb0.418Ta0.328 Ti0.254)35.0Fe31.7Sb33.3 having TC values around 2.25 ± 0.27 W m¹ K-¹.

Tonight, authorities in India revealing new details about what may have caused that horrific train derailment. Based on preliminary findings, officials say it appears a signaling issue led to the crash after a passenger train switched to the wrong track, slamming into a heavy freight train before derailed cars collided with another passenger train.

Down by two, with overtime running out, Philadelphia 76ers star James Harden electrifying his home court crowd. Harden clinching a huge play-off win Sunday with help he says he got from off the court. In a February mass shooting, three Michigan State University students were senselessly killed. Five more were injured. The 76ers say the tragedy left student John Hao paralyzed.

Tonight, the 149th Kentucky Derby making history for the wrong reasons. Seven horses died after spending time at the iconic Churchill Downs race track within days of the Triple Crown's first leg. Among the deaths, two horses racing Saturday just hours before the derby, both were euthanized following severe injuries according to Churchill Downs.

After that catastrophic dust storm engulfed this stretch of Illinois highway, tonight, authorities warning drivers that traveling the same area will again be dangerous and possibly life-threatening. The National Weather Service alert coming as police asked the public for help identifying two of the six people killed in Monday's fiery crash.