Fig. 1. Schematic diagram of electronic energy levels of quantum dots (QDs) and bulk materials

Fig. 2. Surface modification and application of PbSe QDs

Fig. 3. Organic ligand exchange of PbSe QDs^[32]. (a) Carrier mobility as a function of ligand length in bipolar PbSe QDs field effect transistors; (b), (c) first exciton absorption peaks of organic ligand-treated PbSe QDs films and coupling energies, electron mobilities, and optical band gaps of these films

Fig. 4. ALD treatment of PbSe QDs films terminated by short chain ligands. (a) Low temperature ALD fills PbSe QDs films with short chain ligands, short ligand replacement reduces barrier width between QDs, and inorganic matrix filling reduces barrier height and improves carrier mobility^[43]; (b) field-effect electron mobility of filled PbSe QDs at 54 °C and 75 °C as a function of storage time in air^[44]

Fig. 5. PbSe QDs photodetector and its performance^[21]. (a) Dark I-V characteristics of PbSe QDs photodetectors covered with different ligands; (b) BDT treatment of traps in passivated QDs films

Fig. 6. In situ passivation treatment of PbSe QDs^[26]. Transmission electron microscope (TEM) images of PbSe QDs (a) untreated and (b) treated with NH₄Cl, and inset is a high resolution TEM image; schematic diagram of absorption spectra of (c) untreated and (d) treated PbSe QDs with time

Fig. 7. PbSe/CdSe core shell heterostructure. (a) Photoluminescence (PL) spectra of aliquots during CdSe shell formation ^[60]; (b), (c) time dependent PL spectra of PbSe QDs and PbSe/CdSe^[70]

Fig. 8. Preparation of PbSe QDs solar cells^[82]. (a) Schematic diagram and cross-sectional scanning electron microscope (SEM) image of solar cell treated with mixed ligands; (b) J-V curve and corresponding parameters of solar cell

Fig. 9. PbSe photodetector^[93]. (a) Schematic diagram of structure; (b) response and sensitivity

Table 1. Effects of different ligands on properties of PbSe QDs

Table 2. Improvement of fluorescence quantum yield and stability of PbSe QDs by surface passivation technology

Table 3. Applications of PbSe QDs in solar cells