In Situ Fabrication of Highly Luminescent Bifunctional Amino Acid Crosslinked 2D/3D NH₃C₄H₉COO(CH₃NH₃PbBr₃)_n Perovskite Films

Abstract

1603568(1 of 8) photoluminescence (PL) yield for potential optoelectronic application such as in LED and laser devices. [10][11][12][13][14][15][16][17][18] Luminescent MAPbBr 3 films have been deposited onto mesoporous Al 2 O 3 substrate. [19,20] Beside regular bulk lead halide perovskite, 2D or nanostructured lead halide perovskites had been previously synthesized for use as LEDs or other optoelectronic materials. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] These progresses have demonstrated the great success of classic solution chemistry method in the preparation of high quality lead halide nanocrystals with excellent photoluminescent properties for optoelectronic applications.It should be pointed out that although high quality nanocrystals can be successfully fabricated into devices via follow-up processes, a high quality film is more easy-to-process than nanocrystals suspensions for optoelectronic applications. For example, smooth lead halide perovskite films have been directly fabricated via simple one-step or two-step method in solar cell applications. [37] However, we found the high quality smooth planar MAPbBr 3 films for solar cells usually do not exhibit high photoluminescent properties as the nanocrystals suspension or the film deposited in the mesoporous Al 2 O 3 matrix. This is because the MAPbBr 3 films usually consist of large perovskite nanocrystals with size up to hundreds nanometers to micrometers, while the mesoporous support can be used to prevent crystal growth and control the particle size. As recently reported, lead halide perovskite nanoplate with quantum confine without the mesoporous support could grow in large crystals and thus lose the quantum confine effect. [38] It would be urgent to develop a facile method to fabricate highly luminescent perovskite-based film with good controllability and high stability.Metal-organic frameworks (MOFs) are periodic networks formed by coordination of metal ions with organic molecules. This configuration bears the similar structure as the organicinorganic perovskite from the viewpoints that both consist of the metal ions and organic molecules in the framework or lattice. Inspired by the ease preparation and various advantages of the MOFs configuration, [39][40][41] here, we report a strategy for fabricating highly luminescent and stable lead bromide The perovskite quantum dots are usually synthesized by solution chemistry and then fabricated into film for device application with some extra process. Here it is reported for the first time to in situ formation of a crosslinked 2D/3D NH 3 C 4 H 9 COO(CH 3 NH 3 ) n Pb n Br 3n perovskite planar films with controllable quantum confine via bifunctional amino acid crosslinkage, which is comparable to the solution chemistry synthesized CH 3 NH 3 PbBr 3 quantum dots. These atomic layer controllable perovskite films are facilely fabricated and tuned by addition of bi-functional 5-aminovaleric acid (Ava) of NH 2 C 4 H 9 COOH into regular (CH 3 NH 3 )PbBr 3 (MAPbBr 3 ) perovskite precursor solu...

Low‐Dimensional Perovskites: From Synthesis to Stability in Perovskite Solar Cells

“…[117] A notable improvement was realized by Zhang et al in their in situ crosslinking of 2D/3D NH 3 C 4 H 9 COO(CH 3 NH 3 ) n Pb n Br 3n perovskite planar film with tunable quantum confinement in the presence of bifunctional amino acid alongside NH 3 + and COO groups. [118] The crosslinked 2D/3D perovskite quantum dots exhibit comparable PLQY to the one-step synthesis using a classical hot injection method. A group from Stanford University led by McGehee investigated a mixed 2D/3D perovskite (PEA) 2 (MA) 2 [Pb 3 I 10 ] by adopting a one-step solution-processing approach by spin-coating the precursor mixture.…”

Organic–inorganic metal halide hybrids beyond perovskites

“…For instance, a series of nanoscale quasi-2D lead (II) bromide perovskites were obtained by a one-pot synthesis to exhibit tunable emissions from deep blue to bright green [11]. A strategy to obtain crosslinked 2D/3D structure Ava(MAPbBr 3 ) n (Ava = 5-aminovaleric acid) with tunable emission was also reported, serving as a promising approach for in situ deposition of lead halide perovskite films [97]. Bulk quasi-2D perovskites containing lead iodide double layers and large organic cations (bis-protonated 2-(2-aminoethyl)-pyrazole) were developed to show promising PV performance [96].…”

Lead Halide Perovskite Nanocrystals: Stability, Surface Passivation, and Structural Control

“…We suggest that a protonation transfer reaction between carboxylic (‐COOH) and amino (‐NH 2 ) groups results in negatively charged ‐COO − and positively charged ‐NH 3 + groups that can effectively and, respectively, passivate cationic (Pb 2+ or MA + ) and anionic (Br − in this case) surface defect sites on the PNCs surface. As a result of the bi‐coordination effect between Pb 2+ and COO − as well as Br − and NH 3 + , this kind of bifunctional ligands can be used in the synthesis of crosslinked layered perovskites, as shown in Figure a . The protonation strategy can also be realized by using a combination of HBr acid and amino capping ligands as HBr can protonate ‐NH 2 into ‐NH 3 + .…”

“…Various strategies have been reported for controlling the size and shape of PNCs, including varying the reaction temperature and time during synthesis . In addition, capping ligands with different structures and lengths can also affect the nucleation and growth rate owing to their anchoring and steric effects, and thereby the structure of NCs, as has been demonstrated in the synthesis of different dimensional PNCs . Here, we focus on the effect of capping ligands on the structure of PNCs as the effects of reaction temperature and time on the structural control of LH PNCs have been reviewed previously …”

“…As ar esult of the bi-coordination effect between Pb 2 + and COO À as well as Br À and NH 3 + ,t his kind of bifunctional ligands can be used in the synthesis of crosslinked layered perovskites, as shown in Figure 7a. [59] The protonation strategy can also be realized by using ac ombinationo fH Br acid and amino capping ligandsa sH Br can protonate -NH 2 into -NH 3 + . [60] Even though single ammonium capping ligandsc an be appliedi nt he surface passivation of PNCs as the dominant surfacei ons are halides, [54,[61][62][63] the PL QY and uniformity of PNCs obtained are usually worse than that with the combination of carboxylic and amino ligands.…”