NOVELTY - Forming a dense film (110) on a substrate (102) involves formulating an ink of particles in which at least 50% of the particles are microflakes, where each microflake has a non-spherical, planar shape and contains at least one element from group IB, IIIA and/or VIA, and where at least one set of the particles in the ink include inter-metallic microflake particles containing at least one group IB-IIIA inter-metallic alloy phase; and coating a substrate with the ink to form a precursor layer. The ink has a desired stoichiometric ratio of the elements.    USE - For forming a dense film useful in formation of a semiconductor absorber for a photovoltaic device (claimed), and useful in the formation of precursor layers for thin film solar cells; useful for providing high-throughput printing of semiconductor precursor layer; and useful in manufacture of photovoltaic devices and solar cells.    ADVANTAGE - The planar shape of the microflakes creates greater surface area contact between adjacent microflakes, thus forming the dense film at a lower temperature and in a shorter time as compared to a film made from a precursor layer using an ink of spherical nanoparticles having similar material composition as the ink used in the dense film formation method. The planar shape of microflakes can form the dense film at an annealing temperature, at least 50degreesC less as compared to a film made from a precursor layer using an ink of spherical nanoparticles having similar material composition as the ink used in the method. The planar shape of the microflakes creates greater surface area contact between adjacent microflakes relative to adjacent spherical nanoparticles and thus promotes increased atomic intermixing; and creates a higher packing density (e.g. at least 95% packing density) in the precursor layer that forms the dense film, as compared to a film made from a precursor layer made from an ink of spherical nanoparticles having similar material composition as the ink used in the method. The planar shape of the microflakes results in grain sizes of at least 0.5 microns in at least one dimension in the semiconductor absorber of the photovoltaic device. The planar shape of microflakes provides the microflakes with a material property to avoid rapid and/or preferential settling of the particles or microflakes with different material compositions or different particle sizes, when forming the precursor layer; and provides the microflakes with a material property to avoid grouping of microflakes, and particularly undesired grouping of microflakes of a particular class such as microflakes of specific material composition, in the ink, thus enabling a finely and evenly dispersed solution of microflakes, resulting in formation of a good coating; provides microflakes with a material property to avoid grouping of microflakes of a specific phase separation in the precursor layer resulting from the ink; provides microflakes with a material property that reduces surface tension at interface between microflakes in ink and a carrier fluid to improve dispersion quality; and provides the microflakes with a material property that enables a more even distribution of group IIIA material throughout in the dense film as compared to a film made from a precursor layer made from an ink of spherical nanoparticles having similar material composition as the ink used in the method. The ink can be formulated by using low molecular weight dispersing agent due to favorable interaction of the dispersing agent with the planar shape of the microflakes. The ink can be formulated using a carrier liquid and without a dispersant. The substrate can be at different temperatures than the precursor layer during processing, thus enabling the substrate to use materials that melt or become unstable at the processing temperature of precursor layer. Even unstable dispersions using large microflake particles that require continuous agitation to stay suspended still, create good coatings. The method provides more efficient and simplified creation of dispersion of microflakes and its resulting coating to form the dense film; and provides high-throughput printing of semiconductor precursor layer from the microflake particles.    DETAILED DESCRIPTION - Forming a dense film (110) on a substrate (102) involves formulating an ink of particles in which at least 50% of the particles are microflakes, where each microflake has a non-spherical, planar shape and contains at least one element from group IB, IIIA and/or VIA, and where at least one set of the particles in the ink include inter-metallic microflake particles containing at least one group IB-IIIA inter-metallic alloy phase; coating a substrate with the ink to form a precursor layer; and processing the precursor layer in an atmosphere to form a dense film. The overall amounts of the elements from group IB, IIIA and/or VIA contained in the ink are such that the ink has a desired stoichiometric ratio of the elements. The microflakes have an aspect ratio of at least greater than or equal to 10. The microflakes are preferably oxygen-free. The inter-metallic phase is not a terminal solid solution phase or a solid solution phase. An INDEPENDENT CLAIM is included for an ink composition comprising several particles including group IB and/or IIIA elements, and optionally at least one group VIA element, where at least one set of the particles are microflakes containing at least one group IB-IIIA inter-metallic alloy phase.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional diagram illustrating fabrication of a film.    substrate (102)    dense film. (110)