Colloidal PbS Quantum Dots with Low Cost and High Quality

J. Pan, A.O. Ballouli, L. Rollny, O. Voznyy, E.H. Sargent, O.M. Bakr
King Abdullah University of Science and Technology, SA

Keywords: PbS, flow reactor, synthesis, colloidal quantum dots, photovoltaics

Summary:

We report on the dual-temperature-stage flow reactor synthesis of high-quality PbS colloidal quantum dots (CQDs), and compare their quality to the conventional batch synthesis, and single-stage reactor synthesis. Separate stages for nucleation and growth allow a high degree of control over the monodispersity of the CQDs. High photoluminescence quantum yield (50 %) and narrow full width-half max values were achieved for the optimized dual-stage flow-synthesized CQDs. Solar cells fabricated from the flow-synthesized PbS CQDs achieve on-par performance with that of batch synthesized CQDs at a power conversion efficiency of 4.1%. The dual-stage flow reactor approach, with its versatility and rapid screening of multiple parameters, combined with its efficient materials utilization, offers an attractive path to automated synthesis of CQDs for photovoltaics and, more broadly, active optoelectronics.