PVEducation (photovoltaics education) is an online textbook that does an excellent job at introducing the basic concepts of semiconductor physics, solar cell device operation, and characterization. This is a great resource for any new student just getting into PV, regardless of background/major.
This article called "Beginner’s guide to visual analysis of perovskite and organic solar cell current density-voltage characteristicsAn excellent guide", by Le Corre and colleagues, discusses how to interpret J-V curves from organic and perovskite solar cells. The guide can be found on arXiv here.
Written by my PhD advisor, Prof. Jenny Nelson, this textbook offers a more in-depth and detailed introduction into PV. This was my personal introductory textbook and I still refer to it to this day.