In Situ Growth of 3D/2D (CsPbBr₃/CsPb₂Br₅) Perovskite Heterojunctions toward Optoelectronic Devices

Abstract

Two-dimensional (2D) CsPb2Br5 exhibits intriguing functions in enhancing the performance of optoelectronic devices in terms of environmental stability and luminescence properties when composited with other perovskites in different dimensionalities. We built a type I three-dimensional (3D) CsPbBr3/2D CsPb2Br5 heterojunction through phase transition where CsPbBr3 quantum dots in situ grew into 2D CsPb2Br5. A thorough growth mechanism study in combination with excited state dynamic investigations via femtosecond spectroscopy and first-principles calculations revealed that the type I hierarchy enhanced the stability of the heterojunction and spurred its luminous quantum yield by prolonging the lifetime of photogenerated carriers. Mixing the heterojunction with other phosphors yielded white-light-emitting diodes with a color rendering index of 94%. The work thus not only offered one new avenue for building heterojunctions by using the “soft crystal” nature of perovskites but also disentangled the enhanced luminescence mechanism of the heterojunction that can be harnessed for promising applications in the luminescence and display fields.

Room Temperature Synthesis of Stable Zirconia‐Coated CsPbBr3 Nanocrystals for White Light‐Emitting Diodes and Visible Light Communication

“…prepared CsPbBr 3 /CsPb 2 Br 5 perovskite heterojunctions through a phase transition, the PLQY and stability enhanced owing to the heterojunction. [ 53 ] The above‐mentioned methods most generally require high temperature, extra inert gases, and prolonged stirring, [ 8,33,40,48,49 ] which are complicated and time‐consuming. Thus, it is urgent to develop a novel and room‐temperature strategy to result in the uniform morphologies and sizes of NCs, the enhancement of optical performance and stability as well.…”

Advance Optical Properties and Emerging Applications of 2D Materials

“…2D CsPb 2 Br 5 exhibits enhanced performance in optoelectronic devices such as white LEDs. The packaged WLED is (0.33, 0.33), indicating that it emits white light with high color rendering index of ∼94% far superior compared to other reports (Huang et al, 2020). 2D perovskites have also found applications as photodetectors.…”

“…In another study, the SnSedecorated nonlinear device in fiber lasers with ultrashort mode-locked pulses at 1.5 and 2.0 μm was fabricated. Additionally, studies indicated that the material could serve as a good saturable absorber for lasers in the broadband area (Wang Z. et al, 2020).…”

Efficient utilization of light energy based on MoS<sub>2</sub>-XS (X=Al, B, Ga) heterostructures

“…[35] ，其中 S 0 代表结构的平衡面积. 这种情况下，C ij 可以利用第一原理通过以下 表达式来计算： [36] 由于复合结构中不存在诸如悬空键及不饱和键之类的强化学键，两部分之间相互作用相对较 弱，因此材料的性能受弱 vdW 力的影响较为明显 [42] 型异质结不适于光解水催化剂，但其载流子的快速复合可以应用于某些特殊的光电器件，同样有 着广阔的应用潜力 [44,45] . 我们注意到，这种能带变化形式与随后应变引起的变化有很大的不同.…”