Surface modification of CdSe nanocrystals: Application to polymer solar cell

The optimum choice of the ligand that stabilizes the colloidal quantum dots and passivate the surface is crucial for tuning the energy level and remain elusive. The atomic ligand passivation with iodide remains superior over other surface treatments. Herein, we applied the iodide ligand to passivate the CdSe nanocrystals with an excitonic absorption at 2.1 eV by a liquid-liquid extraction process. We took the view of the change in the optical and structural properties upon ligand exchange. Finally, we tested the performance of the iodide treated dots by employing it in an inverted structure polymer solar cell based on P3HT: PCBM. •This paper highlights the role of the iodide ligand passivation on the surface modification of colloidal CdSe nanocrystal.•CdSe QDs have been subjected to full optical and structural characterization to trace the change upon surface passivation.•The iodide treated CdSe dots are then tested in a polymer solar cell based on P3HT:PCBM with an inverted structure.