A Comprehensive Undergraduate Experiment: Bismuth Trichloride-Doped PTAA as Hole Transport Layer for High-Performance Perovskite Solar Cells

This work focuses on the fabrication and optimization of perovskite solar cells (PSCs) and implements project-based teaching in the “Optoelectronic Materials” course for undergraduate materials science majors. By integrating cutting-edge research into undergraduate experimental courses, a comprehensive experiment on “BiCl3-Doped Polytriarylamine (PTAA) as a Hole Transport Layer” is designed. Students were guided through tasks such as literature review, concentration gradient design, fabrication of inverted PSCs, and multidimensional characterization. During implementation, students not only acquired hands-on skills in precision weighing, dissolution, spin coating, annealing, and thermal evaporation but also used characterization techniques including Ultraviolet–visible (UV–vis) absorption spectroscopy, the space-charge-limited current (SCLC) method, and time-resolved photoluminescence (TRPL) to analyze the impact of doping on energy level alignment, hole mobility, and interfacial charge transport. Ultimately, a champion device efficiency of 21.40% was achieved at a doping concentration of 1 mg mL–1. For teaching evaluation, a multistakeholder mixed-methods approach was employed. Statistical analysis of the test scores indicated that this project more effectively promotes the internalization of disciplinary knowledge compared with traditional lecture-based instruction. Instructor observations and peer evaluations further demonstrated that team members actively participated and complied with protocols and that their presentations exhibited clear evidence–reasoning chains. This work provides a good reference for project-based experimental teaching for undergraduate students majoring in Materials Chemistry.