An electrochromic device can include a substrate, a transparent conductive oxide layer over the substrate, and a bus bar over the substrate. The bus bar can include silver and has a resistivity of at most 6.7×10−6 Ω*cm, an average adhesion strength to SiO2 of at least 3N based on 20 measurements, as determined by Method A of ASTM B905-00 (Reapproved 2010), or a classification of at least 4, as determined by Method B of ASTM B905-00 (Reapproved 2010). In another aspect a process of forming an electrochromic device can include forming a transparent conductive oxide layer over a substrate; forming a bus bar precursor over the substrate, wherein the precursor includes silver; and firing the precursor to form a bus bar. Firing can be performed such that the first bus bar is at a temperature of at least 390° C.