Two-photon photoluminescence and bio-imaging application of monodispersed perovskite-in-silica nanocrystals with high biocompatibility

Two-photon absorption in halide perovskites and their applications

“…At the moment, several approaches have been proposed to encapsulate halide perovskite materials in polymer, SiO 2 and glass to increase their stability in water. 25,149,157,175–177,180–182 With all the expectations we discussed above, we are in the right direction to use halide perovskite materials for bioimaging applications.…”

Biomolecules incorporated in halide perovskite nanocrystals: synthesis, optical properties, and applications

“…147,187 At present, there are a handful of proof-of-concept demonstrations of HPNCs used as fluorescent imaging probes in a variety of mammalian cell lines, as well as in E. coli , and most of these do not employ biomolecules as ligands or during synthesis. 112,147,184,185,187,188,191,192,194,232–240 Currently, the main focus of these studies is to demonstrate cellular uptake with minimal toxicity from Pb 2+ leaching and good imaging contrast. Nearly all the reports utilize UV and blue light for excitation, and acquire the images using the green emissions from CsPbBr 3 or red emissions from CsPbI 3 , demonstrating the viability of using HPNCs for basic optical bioimaging.…”

“…This nonlinear, anti-Stokes process is highly attractive because it introduces the possibility to utilize near-infrared (NIR) excitation wavelengths to obtain emissions spanning the UV and visible regions. The upconversion process has been demonstrated for HPNCs through three mechanisms, two-photon absorption (TPA), 237 triplet–triplet annihilation (TTA) 242 and energy-transfer upconversion (ETU). 243 Unfortunately, while TTA-mediated upconversion using HPNCs has seen modest success in photovoltaic applications, there are currently no reports of this phenomenon for bioimaging.…”

“…To our knowledge, all of the current demonstrations of TPA upconversion have been performed using CsPbBr 3 HPNCs excited using 800 nm femtosecond pulsed lasers. 191,234,237 In these cases, two 800 nm photons are simultaneously absorbed by an HPNC, generating one 400 nm photon that is efficiently absorbed by CsPbBr 3 . The green emissions from the nanoparticles are then visualized by microscopy.…”

An effective Fe(ii) doping strategy for stable and highly photoluminescent CsPbBrI2 nanocrystals

“…With the increasing demand for energy conversion, 1–4 optical displays, 5–8 signal detection, 9,10 biomedical imaging, 11,12 and reaction catalysis, 13,14 perovskite (ABX 3 ) materials, in particular all inorganic perovskite nanocrystals (PNCs, A is Cs; B is Pb; X is Cl, Br or I), have attracted considerable attention due to their convenient solution processability, flexible tunability of band gaps from the violet to near-infrared, narrow full width at half maximum (FWHM) and high photoluminescence quantum yields (PLQYs). 15,16 At present, CsPbX 3 NCs with PLQYs over 90% have been achieved, and the corresponding low-threshold amplified spontaneous emissive layers and high-efficiency light emission diodes (LEDs) have been constructed.…”