Here I present my work on developing and evaluating research-based learning tools for quantum mechanics. In particular, I will discuss the development and evaluation of two Quantum Interactive Learning Tutorials (QuILTs) focusing on Degenerate Perturbation Theory (DPT) and a System of Identical Particles. The QuILTs are guided by several learning theories from cognitive science and strive to help students develop a more robust understanding of the concepts covered. The investigation was carried out in advanced quantum mechanics courses by administering free-response and multiple-choice questions and conducting individual interviews with students. It was found that students share many common difficulties related to relevant physics concepts. They had difficulty with mathematical sense-making and applying linear algebra and combinatorics concepts correctly in this novel context of quantum mechanics. I describe how the research on student difficulties was used as a guide to develop and evaluate the QuILTs, which strives to help students develop a functional understanding of concepts necessary for DPT and a system of identical particles. I also discuss the development and validation of the DPT QuILT focusing on these issues and its in-class evaluation in the undergraduate and graduate courses that focused on these issues.