Search materials by HOMO, LUMO and work function I need to search organic semiconductors for organic photovoltaics (OPV) by their HOMO, LUMO, work function at 300K (as I understand, WF cannot be derived from HOMO and LUMO because semiconductor can be differently doped and Fermi level depends on concentration of dopants) and deposition methods (such as CVD, PVD, spin-coating, electrodeposition, etc)..

Is there some free site where I can either download a machine-readable table of needed data or make a search based on that criteria? What is it?
Indeed, Prof. Alán Aspuru-Guzik has placed his "clean energy project" database on the web in a searchable form.

At the moment, it covers ~2.3 million compounds.


  Use of the data requires citation of the appropriate literature sources. The data in this database is released under the Creative Commons Attribution ShareAlike license and therefore any academic publications associated with the CEPDB should be appropriately cited.


As you point out, the database only covers HOMO and LUMO orbital eigenvalues. While this may not be the most useful for experimental applications (i.e., you really want ionization potentials and first excited state energies or electron affinities) it should be a helpful "first screen" to find interesting lead compounds.