PbS Nanocrystal Photodetector Technologies

Light detection is the underlying principle of many optoelectronic systems. For decades, semiconductors such as silicon carbide, silicon, indium gallium arsenide and germanium have dominated the photodetector industry. They can exhibit excellent photosensitivity but are limited by one or more aspect, for example high production cost, high temperature processing, flexible substrate incompatibility, limited spectral range or requiring cryogenic cooling for efficient operation. Recently lead sulphide (PbS) nanocrystals have emerged as one of the most promising new materials for photodetector fabrication. They offer several advantages including low cost manufacturing, solution processability, sizetunable spectral sensitivity, flexible substrate compatibility and have achieved figures of merit outperforming conventional photodetectors. We review the underlying concepts, breakthroughs and remaining challenges in PbS nanocrystal based photodetector technologies.