Effectiveness of spin coating quantum dots deposition process onto mesoporous titanium dioxide for photovoltaic application

Abstract

The aim of this work was to present an effective method for deposition onto a conductive material covered by a thin film on a glass surface using the spin coating technique. The TiO2 layer, consisting of 99% anatase particles (~20 nm diameter), was applied via screen printing to an estimated thickness of ~5 μm onto TCO-coated glass (NEC A7). QDs were deposited using spin coating with controlled parameters: time 90 s, rotational speed 4000 rpm, and acceleration A=100 rpm/s. Three types of colloidal QDs dispersed in toluene were utilized: ZnCuInS/ ZnS (max. em 530 nm ) ZnCuInS/ZnS and (max. em 700 nm), both at 1 g/ml concentration, applied in volumes of 250 μl and 500 μl; and CdS (max. em 460 nm) at 0.5 g/ml concentration, applied in volumes of 500 μl and 1000 μl. Selected samples underwent post-deposition annealing at 250 °C for 15 minutes. Surface morphology was characterized using Scanning Electron Microscopy (SEM) in the backscattered electron (BSE) detector configuration, while optical properties were assessed using double-beam spectrophotometer. In conclusion, the results confirm the effectiveness of the spin coating technique for QDs deposition onto TiO2 layers, validating its potential to enhance optoelectronic performance through improved light absorption and charge separation dynamics crucial for QD-sensitized solar cell applications.