Stable fluorescent NH3 sensor based on MAPbBr3 encapsulated by tetrabutylammonium cations

Luminescence Enhancement, Encapsulation, and Patterning of Quantum Dots Toward Display Applications

“…The long alkyl chain also improved the stability of the MAPbBr 3 PQDs. [134] Besides, with the help of the thiol group, functionalized ligands could be constructed to further encapsulate and stabilize the QDs,which has been discussed in Section 3.1.2. [29,[91][92][93]135] In addition, photopatterned QDs can also be obtained by carefully screening the ligands, which will be discussed in Section 4.2.…”

Resonant Degenerate Four-Wave Mixing at the Defect Energy Levels of 2D Organic–Inorganic Hybrid Perovskite Crystals

“…Organic–inorganic lead halide perovskites are semiconductors that have seen a great increase in interest due to their optoelectronic characteristics. − Three-dimensional perovskites have been shown to have high energy efficiencies, as high as 20% in the case of heterojunction solar cells using an iodide–bromide hybrid perovskite (MA)­Pb­(I 1– x Br x ) 3. In addition to high efficiencies, the ease of synthesis has made them promising candidates in photovoltaic (PV) applications. , However, 3D lead halide perovskites suffer from stability issues, such as high thermal damage potential under irradiation , and decomposition while exposed to water vapor. , Two-dimensional Ruddlesden–Popper hybrid perovskites utilizing a combination of layered 3D perovskites separated by organic cations have been proposed due to increased stability in comparison to 3D perovskites while still maintaining good conversion efficiencies .…”

“…Johnson et al were able to measure the third-order nonlinear susceptibility of methylammonium lead halide films on the order of 1.6 × 10 –6 esu, which is comparable to other materials, highlighting perovskites as a potential candidate for optoelectronic applications . The acceleration in research interest in organometallic lead halides has led to additional novel uses of the material, such as humidity sensing and NH 3 gas detection . However, these samples are prone to defects in their crystal structure, affecting their energy efficiency by introducing nonradiative recombination pathways …”

“…Defects within a crystal structure are abnormalities in the regular structure. Intrinsic defects can take on the form as simple atomic vacancies or interstitials or as more complex antisites (two atoms switch locations). − Extrinsic defects can come in the form of doping the crystal, substituting one atom with that of the dopant. − Both of these types of defects cause changes to the density of states (DOS) of the crystal, fundamentally changing the band structure and subsequent emission properties. ,,,,,− Defects within the crystal structure of organometallic perovskites can lead to a variety of phenomena, including the introduction of nonradiative recombination pathways for the electron–hole pairs to decay into, leading to a quenching of the characteristic band gap emission . In the photovoltaic industry, these phenomena are a hindrance to the conversion efficiency of the PV cell.…”

Detecting alcohol vapors using two-dimensional copper-based Ruddlesden–Popper perovskites

“…Maity et al demonstrated an ammonia sensor based on methylammonium lead iodide, 13 and Li et al used methylammonium lead bromide to detect the same compound. 14 Zhu et al were able to detect p-xylene in the parts per million (ppm) range using (C 4 H 9 NH 3 ) 2 PbI 4 . 15 The capability of methylammonium lead bromide (MAPbBr 3 ) to detect gases, such as oxygen and water vapor, was demonstrated by our group.…”