Aspartic acid adsorption on thermoelectric surfaces

Abstract

Abstract Using molecular dynamics based on density functional theory, interaction of aspartic acid (C4H7NO4) with room-temperature thermoelectrics Bi2Te3, SnSe, MgAgSb, and TiO2 alloyed with V is investigated. Aspartic acid is a common amino acid in mammals, decorating a cell membrane, and hence relevant for biocompatibility. Ti(0001), Zn(0001), Pd(111), Pb(111), and Cu(111) surfaces are employed to gauge such interactions, yielding an approximate adsorption energy threshold of −0.060\u202feV\u202fatom−1. Based on this threshold, Bi2Te3(0001) and SnSe(001) are rendered inert, while MgAgSb(001) and TiO2(001) alloyed with V are proposed to be biocompatible. An aspartic acid molecule undergoes a non-dissociative adsorption on MgAgSb(001). The interaction of aspartic acid with TiO2(001) alloyed with V is characterized by deprotonation of a carboxyl group, a subsequent Ti O interfacial bond formation, and a reaction of an amino functional group with Ti. Short covalent-ionic bonds across these interfaces support the findings. These results may inspire future research on self-powered biomedical devices.