Abstract
Semiconducting thin films made from nanocrystals hold potential as composite hybrid materials with new functionalities. With nanocrystal syntheses, composition can be controlled at the sub-nanometer level, and, by tuning size, shape, and surface termination of the nanocrystals as well as their packing, it is possible to select the electronic, phononic, and photonic properties of the resulting thin films. While the ability to tune the properties of a semiconductor from the atomistic- to macro-scale using solution-based techniques presents unique opportunities, it also introduces challenges for process control and reproducibility. In this review, we use the example of well-studied lead sulfide (PbS) nanocrystals and describe the key advances in nanocrystal synthesis and thin-film fabrication that have enabled improvement in performance of photovoltaic devices. While research moves forward with novel nanocrystal materials, it is important to consider what decades of work on PbS nanocrystals has taught us and how we can apply these learnings to realize the full potential of nanocrystal solids as highly flexible materials systems for functional semiconductor thin-film devices. One key lesson is the importance of controlling and manipulating surfaces.
Highlights
Synthesized semiconductor nanocrystals have become a distinct class of materials, functional in a multitude of optoelectronic applications.[1]
While research moves forward with novel nanocrystal materials, it is important to consider what decades of work on PbS nanocrystals has taught us and how we can apply these learnings to realize the full potential of nanocrystal solids as highly flexible materials systems for functional semiconductor thin-film devices
We focus on lead sulfide (PbS) colloidal nanocrystals since it is one of the most-studied semiconductor nanomaterials.[4]
Summary
Synthesized semiconductor nanocrystals have become a distinct class of materials, functional in a multitude of optoelectronic applications.[1]. We focus on lead sulfide (PbS) colloidal nanocrystals since it is one of the most-studied semiconductor nanomaterials.[4] Due to quantum confinement, the energy band gap of PbS can be increased from the 0.42 eV[5] in bulk to 1.8 eV with 1.2 nm radius nanocrystals.[6] Solar cells, photodetectors, and hybrid infrared cameras benefit from solution-phase processability, high absorption coefficients, and relatively good air stability of PbS nanocrystals.[7,8,9] As a result, PbS nanocrystals have become a model system for which a large number of fundamental, computational and experimental investigations have been performed.[10,11,12] The vast amount of research carried out on PbS make it an ideal system from which to gain valuable insight into colloidal synthesis, post-synthesis treatment, and thin film fabrication This knowledge can be applied to the development of other nanocrystals material systems for optoelectronic devices. Modifications of Oleate-based Synthesis There are a large number of reported modifications to the original oleate-based synthesis of PbS nanocrystals, in which parameters are tuned to improve control over size, composition, and chemical yield of the synthesis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
