Growth of perovskite nanocrystals in poly-tetra fluoroethylene based microsystem: on-line and off-line measurements

Abstract

Cesium lead halide perovskite nanocrystals are photoelectric nanomaterials that have potential applications in a variety of areas due to their excellent photoelectric and tunable photo luminescent properties. In this work, we investigate the synergetic effects of reaction temperature, reaction-capillary length and flow rate on the growth kinetics of perovskite nanocrystals in a PTFE-based microsystem and the photoluminescence characteristics of the perovskite nanocrystals both on-line and off-line. The on-line measurement finds that increasing the reaction temperature leads to the increase of the wavelength of the PL emission peak of the synthesized nanocrystals and reduces the average size of the perovskite nanocrystals synthesized in long reaction-capillaries. The intensity of the PL emission peak of the nanocrystals synthesized at different reaction temperatures decreases with the increase of the flow rate. The off-line measurement reveals that increasing the flow rate generally leads to the blueshift of the PL emission peaks and the decrease of the average size of the perovskite nanocrystals synthesized at the reaction temperature of 160 °C in the capillary length of 60 cm. Increasing temperature leads to the increase of the emission wavelength of the perovskite nanocrystals from 560 to 608 nm. The temperature dependence of the average size of the synthesized nanocrystals with the same synthesis conditions at different temperatures can be described by the Arrhenius relationship with an activation energy of 8.54 kJ mol −1 . Five different cross-sections of the synthesized perovskite nanocrystals are observed, including rhombus, hexagon, rectangle, square and quadrangle with three of them being observed for the first time.

Diffusion-Limited Growth of a Spherical Nanocrystal in a Finite Space

“…The progress in the synthesis of semiconductor nanocrystals has attracted great interest in a variety of applications, including nanoelectronics, , nanophotonics, , and biosensing. − The techniques used to produce semiconductor nanocrystals can generally be divided into two categories: one is the top–down approach involving the “breaking” of bulk-phase materials into objects of nanoscale sizes, − and the other is the bottom–up approach using monomers to construct objects of nanoscale sizes − through physicochemical reactions. Currently, most semiconductor nanocrystals have been synthesized by the bottom–up approach, which involves the solution-route synthesis, such as one-pot approach, − microfluidic systems, ,,− and hydrothermal synthesis. ,, The main challenge in the solution-route synthesis is the size control of nanocrystals, which depends on the processing conditions. The understanding of the spatiotemporal evolution of nanocrystals in the solution-route synthesis is of great importance for both scientific studies and practical applications to better design advanced synthesis techniques for the manufacturing of monodisperse nanocrystals of high quality.…”

Modeling analysis of the growth of a cubic crystal in a finite space

“…According to the photoluminescence (PL) spectrum of semiconductor nanocrystals, 31 the PL intensity as a function of the emission wavelength approximately follows a Gaussian distribution function. It is known that the PL intensity is proportional to the concentration of nanocrystals and the reciprocal of the emission wavelength is a linear function of the reciprocal of the square of the nanocrystal size if the contribution of electrostatic interaction to the change of bandgap is negligible.…”

Importance of Monitoring the Synthesis of Light‐Interacting Nanoparticles – A Review on In Situ, Ex Situ, and Online Time‐Resolved Studies

“…In many kinetic studies, mixing efficiency and reaction times are not properly assessed. [210,304,[329][330][331] As an example, the effect of flow rate on a particular size was investigated in the synthesis of CdSe QDs using a microchannel chip reactor. [305] By decreasing the flow rate from 10 to 0.25 µL, the size increased from 1.05 to 1.52 nm.…”