The main emphasis of this book is ultra-fast charge transfer dynamics of the nanocrystals quantum dots in absence and in presence of molecular adsorbate. The charge transfer dynamics have been demonstrated using different NCs in terms of colloidal quantum dots, core/shell, alloys and the various organic and inorganic molecules. The NCs have been synthesized in non aqueous medium and the morphology are analyzed by XRD, HRTEM, EDX, and optical techniques. The charge carrier dynamics of the composite system have been carried out using time resolved PL and femtosecond transient absorption study. The NCs in different form are employed gradually depending on their application in QDSC. To improve photo-current conversion efficiency in QDSC, the molecular adsorbates have been introduced with the NCs which develop charge separation and prevent the exciton annihilation. This book has nine different chapters including general introduction of quantum dots nano-crystals, experimental setups, and summary and outlooks. The experimental conclusions are relevant towards QDSC are discussed in chapter three to eight.