Performance Enhancement of All-Inorganic Perovskite Quantum Dots (CsPbX₃) by UV-NIR Laser Irradiation

Abstract

Perovskite quantum dots (QDs) have gained significant attention for both fundamental research and commercial applications because of their outstanding optoelectronic properties and tremendous application potentials. Reducing defect density in all-inorganic perovskite QDs is of great importance for performance enhancement. In this work, it is found that the UV-NIR femtosecond laser pulse treatments could increase the photoluminescence quantum yield (PLQY) of the CsPbBr 3 perovskite QDs from 71 to 95%. Such an enhancement could be attributed to decrease of the defects after laser exposure, which is consistent with its red-shifted PL and other characterization results. Furthermore, the dynamics of energy transfer from exciton to trapping in irradiated CsPbX 3 QDs are studied to gain an insight into the relative strength of exciton-trapping exchange coupling. The results confirm that the trapping defects are decreased by laser irradiation, and the mechanism leading to the enhancement of PLQY is revealed. In addition, the enhanced stability of laser-irradiated CsPbX 3 QDs is also testified. Finally, the application of laser-treated perovskite QDs in the liquid crystal display (LCD) backlight film is successfully demonstrated. It is further anticipated that this mechanism is helpful for the design of perovskite-based optoelectronic applications such as LCD technology and light-emitting devices.

Solid‐State Red Laser with a Single Longitudinal Mode from Carbon Dots

“…For instance, organic semiconductors and perovskites usually suffer from severe intrinsic chemical or thermal instability, and external moisture/oxygen‐induced degradation, leading to generally poor operating stability [57, 58] . Laser devices based on all‐inorganic perovskites or colloidal quantum dots have recently achieved laser emission at high temperature (>400 K), potentially offering the stable operation of solid‐state micro/nano laser devices [59, 60] . However, most current operating stabilities remain limited to tens of minutes.…”

Highly Emissive Deep‐Red Perovskite Quantum Dots in Glass: Photoinduced Thermal Engineering and Applications

“…The number of trapping defects in CsPbI 3 QDs may increase by homogeneous heat‐treatment, [ 20,37,38 ] thus reducing the IQE. In contrast, appropriate irradiation of ultrafast laser was reported to reduce the trapping defects in PQDs, [ 39 ] accompanied by an increase in IQE. In our case, the continuous irradiation of ultrafast laser may lead to an in situ decrease in the defects of CsPbI 3 QDs and improve the quality of the interior crystals, which will be confirmed in the following discussions.…”

Solid‐State Red Laser with a Single Longitudinal Mode from Carbon Dots

“…[57,58] Laser devices based on all-inorganic perovskites or colloidal quantum dots have recently achieved laser emission at high temperature (> 400 K), potentially offering the stable operation of solidstate micro/nano laser devices. [59,60] However,m ost current operating stabilities remain limited to tens of minutes. Assessment of the R-CD2 laser deviceso perating stability found that it can operate robustly in atmospheric conditions without encapsulation, al ikely benefit of its aqueous synthesis.Remarkably,its output laser intensity maintained 98 % of its initial value after nearly 8h of continuous operation under 1.5 P th pump fluence (Figure 3g).…”