This thesis presents a study of polystyrene (PS) microgel (MG), hole transfer materials (HTMs) and perovskite solar cells (PSCs) and associated effects to combine them together to increase the stabilities of PSCs. PSCs are a disruptive technology which attract a lot of attention because of their remarkable power conversion efficiency (PCE). However, PSCs are very fragile and easy to be damaged by moisture and oxygen. The PS MGs are solvent-swellable, inherently colloidally stable, hydrophobic, and have good film-forming properties. In the study, we mixed PS MG with three different HTMs, poly(3-hexylthiophene) (P3HT), Poly[bis(4-phenyl)(2,5,6-trimethylphenyl)amine (PTAA) and 2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) to establish a diagram of concentrations of each component to form films. We investigated the morphology and light absorption and photoluminescence (PL) of HTM-MG films spin-coated from HTM-MG dispersions. The films containing flattened MG with an aspect ratio of around 10. MG islands containing packed particles were evident for both pure MG and P3HT-MG.