Analysis of Defects and Traps in N-I-P Layered-Structure of Perovskite Solar Cells by Charge-Based Deep Level Transient Spectroscopy (Q-DLTS)

A series of layered-structure perovskite solar cells with three different HTM layers consisting of P3HT, PBTTTV-h, and spiro-OMeTAD were fabricated to investigate intermolecular and interfacial defect density in the devices. Charge-based deep level transient spectroscopy is a powerful tool for analyzing defects within devices. We observe the improvement of fill factor associated with the defect density, resulting in the reduction of interfacial charge recombination. The hysteresis behavior of the devices depends on the trap concentration in the materials and interfaces by charge trapping as well as the recombination processes. The details are discussed in our report.