Alessandro Troisi is given a lecture on “Searching for the best semiconductors” establishing many back-ground results relevant for Diadem in his invited talk in ICSM2022 Glasgow. You can find him starting off the session on “Theory and Data Science”, July 18th, at the Humanities Lecture Theatre at 10.30. This talk will provide an overview of the three main approaches used within the Troisi group to aid the discovery of new materials (i) high-throughput virtual screening (ii) machine learning and (iii) bottom up construction of physical models. The relation between the tree approaches will be discussed including a methodology for selecting the best strategy given time and budget constraints. The examples cover a number of areas related to organic electronics including charge transport in molecular and polymeric materials, singlet fission, temperature activated delayed fluorescence, organic photovoltaics, emissive materials.