Quantum Dot Perovskite Films*

Inkjet printing of quantum dots(QDs) on to a substrate has several advantages like mass production, tailored patterning, and substrate flexibility. We used a Canon 7220 inkjet printer to print solution based CsPbBr₃ QDs onto glass substrates. We printed one layer and two layer samples of QDs and compared the optical properties to those of a dropcast sample. The crystal structure was characterized by X-Ray diffraction which indicated that the original crystal structure was retained after the inkjet printing process. Absorption spectroscopy measurements showed nearly identical characteristics before and after printing with only a slight red-shift of the absorption edge for the printed samples. The Photoluminescence spectra all show a strong PL peak around 500nm and a much weaker PL peak near 455nm. The carrier dynamics of the two PL peaks were measured using Time Correlated Single Photon Counting, which showed overall faster decay of the 455nm peak than the main 500nm peak. We will also present ultrafast Transient Absorption data where we observe the charge transfer dynamics of CsPbBr₃ QDs printed on ITO substrates.