NOVELTY - Formation of photovoltaic feature, involves printing a primer material onto a substrate; etching the substrate with the primer material to form an etched substrate; printing a precursor composition onto the etched substrate, where the precursor composition comprises at least one of metallic nanoparticles containing a metal and a metal precursor compound to the metal; and heating the precursor composition to form the photovoltaic feature on the substrate.    USE - For forming photovoltaic feature e.g. photovoltaic conductive features including set of finger lines and collector lines deposited at a right angle to the finger lines for solar cell (claimed) useful in electronics, displays and other applications such as transparent antennas for radio frequency tags and smart cards, microelectronic components e.g. multi-chip modules for prototype designs, flat panel displays including plasma display panels, cellular phones, nonlinear devices e.g. thin film transistors, organic thin film transistors, emissive pixels such as electroluminescent pixels, plasma display pixels, field emission displays.    ADVANTAGE - The precursor composition have low processing temperatures to allow deposition onto organic substrates and subsequent heat treatment. The precursor compositions have a low decomposition temperature, thereby enabling the formation of electronic features on a variety of substrates, including organic substrates. The precursor compositions include conversion reaction inducing agents adapted to reduce the conversion temperature of the precursor composition. The precursor compositions can be deposited onto a substrate, and reacted to form highly conductive electronic features having good electrical and mechanical properties. The precursor compositions can be formulated to have a wide range of properties and a wide range of relative cost. For example, in high volume applications that do not require well-controlled properties, inexpensive precursor compositions can be deposited on cellulose-based materials, such as paper, to form simple disposable circuits. The precursor compositions can be utilized to form complex, high precision circuitry having good electrical properties. The conductive electronic features can have good electrical properties. For example, the conductive features have a resistivity of not greater than 20 times (preferably not greater than 2 times) the resistivity of the bulk conductor. The precursor composition does not generate any waste. The photovoltaic feature has a conductivity that is not less than 10% of conductivity of the equivalent pure metal; and resistivity of not greater than 2 times the resistivity of the bulk conductor. The photovoltaic feature is resistant to solder leaching.    DETAILED DESCRIPTION - Formation of photovoltaic feature, involves printing a primer material onto a substrate; etching the substrate with the primer material to form an etched substrate; printing a precursor composition onto the etched substrate, where the precursor composition comprises at least one of metallic nanoparticles containing a metal and a metal precursor compound to the metal; and heating the precursor composition to form the photovoltaic feature on the substrate. The etching comprises locally etching the substrate. The etching inhibits spreading of precursor composition. The etching forms via that is filled with the precursor composition. The precursor composition comprises a paste. The precursor composition is heated at not greater than 300 (preferably not greater than 185degrees C). The metallic nanoparticles have a volume median particle size of not greater than 100 nm. The metallic nanoparticles comprise a cap or coating. The cap or coating comprises an inorganic cap or coating.