Stable, Strongly Emitting Cesium Lead Bromide Perovskite Nanorods with High Optical Gain Enabled by an Intermediate Monomer Reservoir Synthetic Strategy

Abstract

semiconductor nanorods are important for numerous applications ranging from optics and electronics to biology, yet the direct synthesis of high-quality metal halide perovskite nanorods remains a challenge. Here, we develop an intermediate monomer reservoir synthetic strategy to realize the controllable growth of uniform and low-defect CsPbBr 3 perovskite nanorods. Intermediates composed of CsPb 2 Br 5 and Cs 3 In 2 Br 9 are obtained through the substitution of Pb 2+ with In 3+ cations in the template of CsPbBr 3 nanocubes and act as a precursor reservoir to gradually release monomers, ensuring both the slow growth rate and low defects of nanorods. We have used branched tris(diethylamino)phosphine as a ligand, which not only has unequal binding energies with different crystal faces to promote the orientation growth but also provides strong steric hindrance to shield the nanorods in solution. Because of minor amount of defects and an effective ligand passivation, in addition to significantly enhanced stability, the perovskite nanorods show a high photoluminescence quantum yield of up to 90% and exhibit a net mode gain of 980 cm −1 , the latter being a record value among all the perovskite materials. An extremely low amplified spontaneous emission threshold of 7.5 μJ cm −2 is obtained under excitation by a nanosecond laser, which is comparable to that obtained using femtosecond lasers in other recent studies.

Amplified Spontaneous Emission and Lasing in Lead Halide Perovskites: State of the Art and Perspectives

“…A very interesting and recent step in the development of perovskite NCs with optimized optical properties was reported by Wang et al [38], who developed a novel synthetic strategy, called intermediate monomer reservoir synthesis, allowing the growth of highly uniform, low defect and stable CsPbBr 3 nanorods with PLQY of 90% (see Figure 3a). A detailed comparison with CsPbBr 3 nanocubes based on the investigation of the PL temperature dependence allowed to demonstrate a much lower defect trap states in nanorods.…”

“…The main ASE (wavelength and threshold) and pump laser properties (wavelength and time length) of all the discussed materials are summarized in Table 1. [38]. American Chemical Society, 2019.…”

Investigation of the Role of the Environment on the Photoluminescence and the Exciton Relaxation of CsPbBr3 Nanocrystals Thin Films

“…In particular, perovskite nanocrystals (NCs) are very interesting due to the possibility to engineer the optical properties by acting on the chemical composition [1], the size, the shape [2,3], and even the crystalline packing dimensionality within each NC [4]. Moreover, efficient NCs electroluminescence [5] and low threshold amplified spontaneous emission [6][7][8][9] have been demonstrated, thus proposing them as possible active materials in LEDs and lasers.…”

Facile Synthesis of FAPbI3 Nanorods

“…Until now, perovskite NRs can be fabricated by indirect synthetic methods such as chemical transformation from Cs 4 PbBr 6 nanopolyhedrons [12] or chemical cutting of nanowires [13]. The direct synthetic methods reported so far normally require higher energy ultrasonication [14] or high temperatures [15]. Because of the ionic nature of perovskite compounds, the controllability of both morphology and size remains unsatisfactory in direct synthesis.…”