Long carrier lifetime in faceted PbS quantum dot superlattice fabricated by sedimentation method

Abstract

We fabricated colloidal quantum dot (QD) superlattice films and investigated their primal optical properties. The films were prepared by depositing faceted PbS QDs on pyramidal-microhole-array template and flat substrate in solution. The red shift in the quantum state emission of QDs was observed in photoluminescence spectra after film formation, which suggested the weakened quantum confinement of carriers in intermediate bands. Emission decay curves at the excited states in the QD superlattice film were double exponential. The longer lifetime was several tens of nanoseconds and attributed to the carrier delocalization in the intermediate bands. The emission lifetime of the QD film prepared on the template was found to be more than twice as long as that on the flat substrate, which suggested that the template helped to form large area QD superlattice.

Development of Self-Assembly Methods on Quantum Dots

“…By using a template, they deposited PbS QDs onto a microporous array template to form a superlattice thin film [ 47 ]. As shown in Figure 6 , it was found that the higher-order emission lifetime on the template was more than twice that on the planar substrate.…”

“…( b ) μ-PL spectra and decay curves of the QDs films prepared for 7 d on a template. The vertical axes of the decay curves are the natural logarithm of PL intensity [ 47 ]. Copyright 2020, Japanese Journal of Applied Physics .…”

Study on chemical synthesis of SnSSe nanosheets and nanocrystals

“…Semiconductor nanocrystals have been studied for application to various electronic and optoelectronic devices such as transistors, [1][2][3] semiconductor lasers, [4][5][6] solar cells, [7][8][9][10][11] photodetectors, [12][13][14] sensors, [15][16][17] and quantum devices. [18][19][20] These device properties are highly dependent on the shape and size of the nanocrystals.…”

Theoretical study of multi-band solar cells with a single PbS quantum dot superlattice film as a light absorption layer

“…On the other hand, we have proposed the use of colloidal QDs to compose a single crystal-like QDSL based on the deposition method. [12][13][14][15][16] Colloidal QDs can be mass-produced in flasks at low cost with uniform shape. There is no essential problem in applying colloidal QDs to solar cells, and they have been studied for use as sensitizers or spin-coated films as light absorption layers.…”