Correlation between Annealing-Induced Growth of Nanocrystals and the Performance of Polymer: Nanocrystals Hybrid Solar Cells

In this work, we investigated the correlation between the inner structure of aqueous solution processed polymer:nanocrystals (NCs) hybrid solar cells and its performance. By altering the compositional concentration, annealing temperature, annealing time, and the thickness of the active layer, the diameter of CdTe NCs increased from 2.8 nm to tens of nanometers. Also, the performance of poly (1,4-phenylene vinylene) (PPV):CdTe hybrid solar cells changed accordingly. Systematical analysis revealed that the best performance of hybrid solar cells was achieved when CdTe was 30 mg/mL and the annealing temperature was above 250 °C with the active layer thickness of about 100 nm. The inner structure showed the size of CdTe NCs was around 26 nm, with the spacing of 6–12 nm. The data of transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed that the CdTe NCs grew mainly via dynamic coalescence