AbstractHybrid organic-inorganic nanocomposite materials have emerged as one of the most potential alternative candidate to silicon as future optoelectronic material due to their unique optical and electrical characteristics. However, current fabrication process involving synthesizing the pre-made nanoparticles inside the polymer matrices is tediously complex, costly and time consuming. In this research, two approaches in preparing nanocomposite thin films, in situ hybridization and ex situ hybridization, were studied and the results were compared. In situ hybridization, a novel method, where the nanoparticles were grown directly in the Poly(3-hexylthiophene) (P3HT) mixed with stearic acid layers by exposing the films to either H2S or H2Se gas. Ex situ hybridization were done by mixing pre-made CdS or CdSe quantum dots into P3HT solution. For both approaches, depositions of thin films on the solid substrate were done by employing modified Langmuir-Blodgett technique. Studies on Langmuir layer .....