As used herein, the term “substantially free of mixed oxides” is intended to include inorganic (e.g. oxide) particle mixtures which contain no intentionally added mixed oxides. For example, the inorganic (e.g. oxide) particle mixture may include less than 0.1 wt % mixed oxide, for example less than 0.05 wt %, less than 0.01 wt % or less than 0.005 wt % mixed oxide. For example, the inorganic particle mixture may include no intentionally added mixed oxide. As used herein, the term “substantially free of mixed metal compounds” should be interpreted analogously.

Mixed oxides are known in this art. In prior art glass frit formation techniques a mixed oxide is generally formed. The present inventors have surprisingly found that the oxides and other starting materials used to make such a glass in the prior art can instead be prepared (for example by blending or co-milling) to give an inorganic (e.g. oxide) particle mixture in substantially crystalline, particulate form and yet the same or better results achieved.

Except where specified otherwise, the inorganic compound contents described herein are given as weight percentages. These weight percentages are with respect to the total weight of the inorganic particle mixture. The weight percentages are the percentages of the components used as starting materials in preparation of the inorganic particle mixture or conductive paste, on an oxide basis unless specified otherwise.

The inorganic particle mixture described herein is not generally limited. Many different oxides which are suitable for use in conductive pastes for solar cells are well known in the art.