Some yeras ago Professor Hart decorated the halls of of the chemistry building of Michigan State University with posters of famous chemists. May be MSU can help you.
The old Chemical Heritage Foundation, now the Science History Institute, has a lot of information on their website. Historical Biographies | Science History Institute
Sarah Reisert from SHI has said you are welcome to make posters by cutting and pasting info from their website. Maybe just credit them somewhere on the poster?