Ultra‐Thermostability of Spatially Confined and Fully Protected Perovskite Nanocrystals by In Situ Crystallization

Abstract

Although all‐inorganic perovskite materials present multiple fascinating optical properties, their poor stability undermines their potential application in the field of multi‐color display. Herein, spatially confined CsPbBr3 nanocrystals are in situ crystallized within uniform mesoporous SiO2 nanospheres (MSNs) to regulate their size distribution, passivate their surface defects, shield them from water/oxygen, and more importantly, enhance their thermotolerance. As a result, the remnant PL intensity of the prepared spatially confined perovskite (CsPbBr3) nanocrystals by in situ crystallization within uniform mesoporous SiO2 nanospheres (SCP@MSNs) powders can be maintained over 98% of its initial value even after being immersed in harsh conditions (0.1 m HCl or 0.1 m NaOH) for 60 days. Furthermore, the prepared SCP@MSNs‐PDMS film demonstrates astonishing thermostability by maintaining almost consistent room temperature PL intensities after continuous heating–cooling cycles between 200 and 25 °C, which would greatly improve its processability during potential industrial manufacturing. The fabricated LCD backlit based on SCP@MSNs covers 124% of NTSC standard and 95.6% of Rec. 2020 standard, indicating its great potential in practical display field.

One-Step Melt Closed Mesoporous SiO2 for Large-Scale Synthesis of Confined CsPbX3 (X = Cl, Br, and I) Quantum Dots and LED Applications

“…The average lifetimes τ avg of the blue, green, and red composites are 51.0, 57.8, and 166.3 ns, respectively. Compared with other reported high-temperature solid-state methods, , the longer lifetime of our synthesized samples indicates reduced nonradiative decay and fewer defect states of CsPbX 3 NCs, which also means that the CsPbX 3 NCs filled into the SiO 2 pores are effectively passivated.…”

Intrinsic stability of perovskite materials and their operational stability in light-emitting diodes

“…This temperature is highly detrimental to the MHPs and the corresponding fabricated LED. Therefore, several passivation strategies are employed to thermally stabilize the MHPs, such as encapsulation, [124][125][126][127][128][129] doping by bivalent metal cations, [130][131][132][133][134][135] incorporating the various composition of organic-inorganic parts, 63,136 and liquid annealing. 137 The encapsulation provides surface protection to the perovskite materials from the environment, inhibits the agglomeration of perovskite nanocrystals, confines the perovskite crystal size, and prevents degradation from post-deposition treatments and ion exchange reactions which mitigates the optical quenching.…”

“…137 The encapsulation provides surface protection to the perovskite materials from the environment, inhibits the agglomeration of perovskite nanocrystals, confines the perovskite crystal size, and prevents degradation from post-deposition treatments and ion exchange reactions which mitigates the optical quenching. 138 The encapsulation materials must be low cost, spectrally transparent, chemically inert and stable at high temperatures. Therefore, encapsulation is carried out using polymers and porous materials such as SiO 2 , ZrO 2 , TiO 2 , Al 2 O 3 , and others, 139 core-shell materials, 140,141 metal-organic frameworks 142 and inorganic salts.…”

“…However, it has been found that sealed surface pores of SiO 2 provides better stability than an unsealed one. Li et al 138 synthesized CsPbBr 3 nanocrystals via in situ crystallization within mesoporous SiO 2 nanospheres. This process helps to achieve uniform size distribution in confined spaces and sealed perovskite nanocrystals (PNCs) in mesoporous SiO 2 .…”

A highly stable CsPbBr3–SiO2glass ceramic film sintered on a sapphire plate for laser-driven projection displays

“…[23][24][25] However, the stability of CsPbBr 3 NCs is poor in practical applications when they are exposed to light, moisture, and heat. [26][27][28][29] Thus, to overcome this issue, the common approach is to enhance the stability of NCs with inert materials [30][31][32] or barrier matrices. [33][34][35] In 2021, Lin et al 36 firstly developed a CsPbBr 3 glass-ceramic, which was synthesized by co-sintering CsPbBr 3 NCs@glass and low-melting glass frit on a sapphire plate, and also demonstrated the applicability of CsPbBr 3 NCs for laser projection.…”