Improving the efficiency of thermoelectric devices is critical to their widespread adoption. Here a design methodology, formulated on computational and analytical modeling, derives the optimum efficiency and geometry of segmented Bi2Te3-PbTe Thermoelectric Generators (TEGs) between approximate to 298 K and approximate to 623 K (Delta T approximate to 325 K). Comparisons between the different TEG designs, in terms of the electrical load to TEG electrical resistance ratio (m = R-L/R-TEG), are simplified thanks to the devised maximum efficiency to temperature gradient (beta(max) = eta/Delta T) metric. Quasi-computational results of beta(max), show that the collective Seebeck coefficient Bi2Te3-PbTe ((alpha) over tilde) design sustains a higher electrical load in relation to the homogeneous Bi2Te3 and PbTe materials. The average ((alpha) over bar) and collective ((alpha) over tilde) Seebeck coefficient Bi2Te3-PbTe configurations, in comparison to Bi2Te3 and PbTe, exhibit a considerably higher (60-68%) source and sink thermal resistance matching (Theta(TEG) = Theta(Hx)). The proposed segmented Bi2Te3-PbTe ((alpha) over tilde) TEG yields a peak efficiency of 5.29% for a Delta T of 324.6 K. (C) 2012 Elsevier Ltd. All rights reserved.