Exploring the Potential of Colloidal Quantum Dots for Near‐Infrared to Short‐Wavelength Infrared Applications

Abstract

Colloidal quantum dots (CQDs) are powerful components for next‐generation infrared (IR) optoelectronic devices owing to their confinement‐based bandgap‐tunability, cost‐efficiency, and solution‐processability. The strong absorption feature of CQDs from the near‐infrared to short‐wavelength infrared renders them ideal as absorbers in both photovoltaics (PVs) and photodetectors (PDs). To effectively integrate CQDs into these devices, a better understanding of their film properties and a refined approach to material and device architecture are essential. Additionally, compliance with environmental standards for the material design presents a challenge for their widespread application. Therefore, the essential characteristics of CQD films to design optimal IR harvesting optoelectronics are highlighted, for instance, the spectral range, doping polarity/concentration, and energy levels. Subsequently, recent advancements in CQD‐based tandem PVs are explored, covering the key considerations in the fabrication of two‐terminal devices and strategies for enhancing the power‐conversion‐efficiency of large‐sized CQD‐based PVs. The study then explored a CQD‐based photodetector, highlighting the approaches for reducing the dark current and improving the external‐quantum‐efficiency, and the recent progress in Pb‐free CQD PDs is discussed. Finally, the perspectives regarding the current challenges and future directions that are critical for advancing the field of PV and PD are presented.

Surface-Originated Weak Confinement in Tetrahedral Indium Arsenide Quantum Dots

“…This observation is consistent with the previous results reported by Zhao et al about higher FET mobilities in tetrahedral InP NC films compared to the spherical one. The higher electron mobility of QD films can be explained by the larger volume fraction of inorganic core in QDs within the assembled films, which is determined by the volume of the QDs, interparticle distance, arrangement pattern, and packing density of QD assembly. , Both QDs are randomly assembled in the film, as confirmed by grazing incidence small-angle X-ray scattering (GISAXS) patterns (Figure S21). Considering the center-to-center distance ( d q ) extracted from horizontal line-cuts, the estimated volume fraction is 57.2 and 31.2% for tetrahedral and spherical QD films, respectively (Table S4).…”