TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal powder comprises copper. The substrate is conductive; comprises aluminum, and/or silver; is a dielectric; comprises silicon; comprises a solderable metal; or comprises a non-solderable metal. Preferred Composition: The metal and solder powders are collectively present in an amount of (50-95 wt.% based on the total weight of the composition); the metal powder is present in an amount of (35-85 wt.% based on the total weight of the composition); and/or the solder powder is present in an amount of (25-75 wt.% based on the total weight of the composition). The composition further comprises a titanate as an adhesion promoter.    TECHNOLOGY FOCUS - METALLURGY - Preferred Components: The solder powder comprises at least one tin (Sn) alloy and not greater than 0.5 wt.% of mercury, cadmium, and/or chromium; and/or lead (preferably the solder powder comprises a tin-bismuth (SnBi) alloy, and/or a tin-silver (SnAg) alloy). The solder powder has a melting temperature of not greater than 300 degrees C.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The composition further comprises an additive comprising a solvent, and/or an adhesion promoter. The composition comprises the dicarboxylic acid (0.05-1 wt.% based on the total weight of the composition), and the monocarboxylic acid (0.25-1.25 wt% based on the total weight of the composition). The composition further comprises a silane as an adhesion promoter. Preferred Components: The dicarboxylic acid is dodecanedioic acid (DDDA). The monocarboxylic acid is neodecanoic acid.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer comprises an epoxy resin; and/or the carboxylated-polymer comprises an acrylic polymer. The carboxylated-polymer comprises a styrene-acrylic copolymer. Preferred Composition: The polymer and the carboxylated-polymer are collectively present in an amount of (2.5-10 wt.% based on the total weight of the composition); the polymer is present in an amount of (0.5-5 wt.% based on the total weight of the composition); and/or the carboxylated-polymer is present in an amount of (1-7.5 wt.% based on the total weight of the composition). The polymer and the carboxylated-polymer are present in a weight ratio of 1:1 to 1:3 (polymer:carboxylated-polymer). EXAMPLE - A test composition for conductor was formed by using polymer (solid epoxy resin comprising reaction product of epichlorohydrin and bisphenol A and having epoxide equivalent weights (EEW) of 500-560 g/eq) (1.7601 wt.%); additive 1 (monoterpene alcohol) (2.0467 wt.%); additive 2 (styrene dibromide) (0.2865 wt.%); carboxylated polymer (low molecular weight styrene-acrylic copolymer having acid value of 238 (on solids)) (3.7208); dicarboxylic acid (0.2489 wt.%); monocarboxylic acid (0.4953 wt.%); additive 3 (propylene glycol) (1.8608 wt.%); additive 4 (benzyl alcohol) (1.8608 wt.%); metal powder (copper powder) (47.72 wt.%); solder powder 1 (Sn42/Bi58 alloy, having melting temperature of 138 degrees C) (15.625); and solder powder 2 ((Sn96.5/Ag3.5 alloy, having melting temperature of 221 degrees C)) (24.375 wt.%). A series of 5 inch (12.7 cm) monocrystalline silicon cells (wafers) were prepared for application of Cu paste. The Cu paste was diluted down with 1 wt.% butyl carbitol to improve print rheology. The Cu paste was printed on wafers to form Cu busbars via busbar screen from Sefar, stainless steel screen of 325 or 165 mesh, with 12.7 mu m emulsion thickness (PEF2), and a 22 degrees or 45 degrees rotation of mesh. Printing was performed with AMI screen printer with 0.68 kg down force, with 200 mu m blank wafer on stage. Print speed was set to 3-5 inch/second in print-print mode. The wafers were printed and put through BTU Pyramax N2 reflow oven. Durability of Cu busbars under damp heat (DH; 85 degrees C, 85% relative humidity) aging conditions was determined. Unencapsulated prints of Cu busbars on silicon were used to monitor Cu bulk resistivity. The quality of tabbing/Cu busbars was also monitored using contact resistivity by utilizing TLM method. After 1000 hours of exposure to DH, no degradation of Cu busbars was seen relative to Ag busbars. Current-voltage (I-V) measurements using flash tester (Berger PSS 10 II) were performed. The Cu busbars showed increased Voc and Jsc compared to comparative Ag busbars in front busbar examples. Specifically, cells including Cu busbars showed distinct improvement in Voc and Jsc, relative to cells including Ag busbars. The increase generally corresponded to 0.6% and 2.59% relative increase in Voc and Jsc, respectively. This increase was attributed to reduction of metal/silicon contact area.