Spatially Confined CdS NCs in Situ Synthesis through Laser Irradiation of Suitable Unimolecular Precursor-Doped Polymer

The in situ synthesis and patterning of CdS nanocrystals (NCs) is obtained by laser processing of a transparent polymer matrix doped with a cadmium thiolate methylimidazole (MI) modified complex, [Cd(SBz)2]2·MI. The precursor molecule structure ensures a uniform distribution inside the polymer and gives rise to a regular and homogeneous network of CdS NCs in the quantum size regime with a finely tunable bandgap by varying the laser fluence in the range 25–75 mJ cm–2 and shot number from 10 to 100. The simultaneous in situ synthesis of CdS NCs and patterning has been performed in confined regions with a 10 μm resolution by scanning the focused laser beam in the polymer/precursor composite. The emission signal of the irradiated regions presents contributions from both the band gap and the defect emission band, around 3.4 and 2.2 eV, respectively, the relative intensity of them depending on the laser fluence and number of shots. Complex geometries of μ-patterned CdS NCs inside the polymer matrix are achievable, thus enlarging the perspectives in the development of nanodevices and organic light emitting diode (OLED) systems.