The International symposium “Photovoltaics, Solar Energy Materials & Thin Films” was held in Cancun, Mexico from 20 to 24 August 2006. More than 80 participants from different countries attended the symposium, and was one of the most successful symposia of the International Materials Research Congress-IMRC 2006. The major areas of interest in the symposium were: thin film photovoltaics based on CdTe and CI(G)S; polymer photovoltaics; dye-sensitized TiO2 solar cells; and material characterization. A good number of papers presented in the technical sessions were related to development and characterization of thin films of CdTe, CdS, CI(G)S, ZnO and SnO2 and the devices. Seventeen invited talks in the above areas gave opportunities for much focussed discussion, and all who attended could benefit from the new ideas and collaboration opportunities emerged as a result of this symposium.

This special issue contains some of the selected papers presented in the symposium. All the papers were refereed according to the guidelines of the Journal of Material Science: Materials in Electronics. I am grateful to the reviewers who spared their valuable time and for their sincere efforts in maintaining the quality of the papers. I would like to express my sincere thanks to Prof. Safa Kasap and Prof. Arthur Willoughby for the kind help in bringing out this special issue, and to the JMSE editorial staff who have contributed to the publication of this issue.

I acknowledge the Centro de Investigacion en Energia-UNAM for the support provided in organizing the symposium and to the members of the International organizing committee. I also thank the invited speakers and contributors to the technical sessions for making this symposium a success.