Heterogeneous system synthesis of high quality PbS quantum dots for efficient infrared solar cells

As promising optoelectronic materials,lead sulfide quantum dots(PbS QDs)have attracted great attention.However,their applications are substantially limited by the QD quality and/or complicated synthesis.Herein,a facile new synthesis is developed for highly monodisperse and halide passivated PbS QDs.The new synthesis is based on a heterogeneous system containing a PbCl_(2)-Pb(OA)_(2)solid-liquid precursor solution.The solid PbCl_(2)inhibits the diffusion of monomers and maintains a high oversaturation condition for the growth of PbS QDs,resulting in high monodispersities.In addition,the PbCl_(2)gives rise to halide passivation on the PbS QDs,showing excellent stability in air.The high monodispersity and good passivation endow these PbS QDs with outstanding optoelectronic properties,demonstrated by a 9.43%power conversion efficiency of PbS QD solar cells with a bandgap of~0.95 eV(1,300 nm).We believe that this heterogeneous strategy opens up a new avenue optimizing for the synthesis and applications of QDs.

Perovskite bridging PbS quantum dot/polymer interface enables efficient solar cells

Conjugated polymers have been explored as promising hole-transporting layer(HTL)in lead sulfide(PbS)quantum dot(QD)solar cells.The fine regulation of the inorganic/organic interface is pivotal to realize high device performance.In this work,we propose using CsPbI_(3) QDs as the interfacial layer between PbS QD active layer and organic polymer HTL.The relative soft perovskite can mediate the interface and form favorable energy level alignment,improving charge extraction and reducing interfacial charge recombination.As a result,the photovoltaic performance can be efficiently improved from 10.50%to 12.32%.This work may provide new guidelines to the device structural design of QD optoelectronics by integrating different solutionprocessed semiconductors.