Potentially low-cost high-throughput approaches have been demonstrated that form inorganic semiconductor films directly from nanoparticle or molecular inks. The highest efficiency devices have been prepared with CuInGaSe2 utilizing hydrazine as a solvent and complexing agent. Here, we present our progress to develop of a class of solution-phase routes to Cu2ZnSn(S,Se)4, Cu(In,Ga)(S,Se)2 and most recently bismuth halides that do not use suspensions of nanoparticles or hydrazine. We have discovered new effects of alloying and doping using a combinatorial ultrasonic spray coater and high-throughput screening method to map the optoelectronic properties of absorber layers. The presentation will focus on: (i) the formation of films and elimination of deleterious elements, (ii) incorporation of dopants and their effects of absorber properties and grain boundaries, (iii) alloying to form record high open circuit voltage relative to the maximum theoretical open circuit voltage for the bandgap, (iv) a new understanding of grain growth and impurity removal in kesterites, and recent results to yield tandem solar cells with hybrid perovskites.
 Xin, H., Vorpahl, S.M., Collord, A.D., Braly, I.L., Uhl, A.R., Krueger, B.W., Ginger, D.S., Hillhouse, H.W., Phys. Chem. Chem. Phys. 17, 23859-23866 (2015).
 Uhl, A.R., Katahara, J.K., Hillhouse, H.W., Energy & Environmental Science 9, 130-134 (2016).
 Collord, A.D., Hillhouse, H.W., Chem. Mater. 28, 7, 2067–2073 (2016).
 Clark, J.A., Uhl, A.R., Martin, T., Hillhouse, H.W., Chem. Mater. ASAP, DOI: 10.1021/acs.chemmater.7b03313, (2017).
 Uhl, A.R., Yang, Z., Jen, A.K.-Y, Hillhouse, H.W., J. Mater. Chem. A 5, 3214-3220 (2017).
 Williamson, B.W., Eickemeyer, F.T., Hillhouse, H.W., Submitted.