A class of materials called perovskites has emerged as a promising alternative to silicon for making inexpensive and efficient solar cells. But for all their promise, perovskites are not without their downsides. Most contain lead, which is highly toxic, and include organic materials that are not particularly stable when exposed to the environment.   Now a group of researchers at Brown University and University of Nebraska – Lincoln (UNL) has come up with a new titanium-based material for...