Fabrication of solution-processed photoactive polymer- and halide perovskite-based solar cells

In the current work, different architectures and photoactive materials have been investigated in order to fabricate low-temperature solution-processed solar cells using dip and spin coating methods. Inverted bulk heterojunction structure has been utilised in fabrication of polymer solar cells using dip coating method. In this structure, all layers except electrodes were deposited using dip coating method, which demonstrated an excellent potential to produce large-scale area PV devices. Formulation of solutions (using different solvents) of hole transport layer, active layer, and electron transport layer play a key role in producing uniform thin films as well as compatibility with dip coating method. The best PV device achieved ~ 3.4% power conversion efficiency. On the other hand, planar heterojunction structures have been employed to produce perovskite-based solar cells using one and two step spin coating methods (OSSCM & TSSCM). Thorough investigations of controlling the morphology of the perovskite films have been carried out using low-temperature processing methods. It was found that it is difficult to control the morphology via OSSCM without additives or using solvent engineering. Controlling the morphology of the perovskite films was achieved via TSSCM after optimizing process parameters such as the concentration of methylammonium iodide (MAI), allowed reaction time (Art), and thermal annealing. In this work it has been established that the best morphology of the perovskite film was achieved when the 1.0 wt% MAI solution was loaded at 60 sec on top of the pre-coated PbI2 followed by thermal annealing for two hours.