Dalton Transactions Dynamic Article Links Cite this: Dalton Trans., 2012, 41, 10497 www.rsc.org/dalton PERSPECTIVE Single source molecular precursor routes to lead chalcogenides† Nathaniel Owusu Boadi, a,b Mohammad Azad Malik, a Paul O’Brien* a and Johannes A. M. Awudza b Received 18th April 2012, Accepted 20th June 2012 DOI: 10.1039/c2dt30849e The use of single-source molecular precursors for lead chalcogenide thin films by CVD or as nanoparticles by solution methods is reviewed. The potential applications of these materials in solar energy are discussed along with the relative advantages of the various methods. 1. Introduction There is considerable current interest in metal chalcogenides (sulfides, selenides or tellurides) stemming from their useful properties as thin films or in highly dispersed form. 1 Potential applications of these materials are in devices such as solar cells (II–VI and III–VI), infrared detectors (IV–VI) and in room-temp- erature thermoelectric generators (V–VI). Simple, inexpensive and environmentally benign protocols are needed that also provide control over issues such as composition, size and mor- phology; facilitating the use of these materials in light emitting diodes, non-linear optics, lasers or solar cells. 2 Lead is classified as a borderline soft metal in the hard/soft acid–base concept of Pearson 3 and shows a wide variety of coordination numbers. Lead(IV) compounds are known to have coordination numbers between 4 and 8, but the majority of them have the coordination number four. Lead(II) can bind as few as two and as many as 10 ligands, with preferred coordination numbers of 4 or 6. 4 Lead(II) forms stable complexes with both soft and hard donor atom ligands. In similar coordination environments, the affinity of lead(II) towards sulfur-based ligands tends to be higher than for harder oxygen- or nitrogen- donor groups. Despite considerable study of the coordination chemistry of lead(II) with S- or Se-donor atom ligands 5 the rational design of complexes remains a challenge. Tuning of the structure of the ligands to satisfy the coordination preferences and requirements of the lead(II) atom is still not that well under- stood; 6 the same is true in design of precursors for chalcogen- ides. Lead(II) complexes with sulfur, selenium or tellurium donor atom ligands have been studied widely during the last few decades. 5 The reason for the sustained interest in these com- pounds lies in their significant structural diversity and potential for applications. 6 Lead chalcogenides in various forms with critical dimensions on the order of nanometers have attracted considerable interest because of their unique physical and chemical properties and Nathaniel Owusu Boadi Nathaniel Owusu Boadi is a Lecturer of Inorganic and Environmental Chemistry at the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. He is currently a beneficiary of the Royal Society, Leverhulme Africa Award Grant Scheme, pursuing a collaborative research with the School of Chemistry, Uni- versity of Manchester, United Kingdom, on synthesis of new precursor materials for the production of solar cells under the supervision of Prof. Paul O’Brien. Mohammad Azad Malik Mohammad Azad Malik com- pleted his PhD Degree at Uni- versity of London in 1990 and then worked as a research fellow with Prof. Paul O’Brien initially at Queen Mary Univer- sity of London (1990–1995), then at Imperial College (1995–2000) and currently as a senior research fellow in The University of Manchester (2000–). He has a wide range of experience in designing and synthesis of single source mol- ecular precursors for II/VI, III/V, III/VI, and IV/VI semiconduc- tors and preparation and characterization of thin films and nanoparticles. † Dedicated to Professor David Cole-Hamilton on the occasion of his retirement and for his outstanding contribution to transition metal catalysis. a Schools of Chemistry and Materials, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK. E-mail: paul.obrien@manchester.ac.uk b Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana This journal is © The Royal Society of Chemistry 2012 Dalton Trans., 2012, 41, 10497–10506 | 10497