Surface ligand engineering, seed introduction and external driving forces play major roles in controlling the anisotropic growth of halide perovskites, which have been widely established in CsPbBr nanomaterials. However, colloidal CsPbI nanocrystals (NCs) have been less studied due to their low formation energy and low electronegativity. Here, by introducing different molar ratios of surface acids and amines to limit the monomer concentration of lead-iodine octahedra during nucleation, we report dumbbell-shaped CsPbI NCs obtained by the self-assembly of nanospheres and nanorods with average sizes of 89 nm and 325 nm, respectively, which showed a high photoluminescence quantum yield of 89%. Structural and surface state analyses revealed that the strong binding of benzenesulfonic acid promoted the formation of a Pb(SO)-rich surface of CsPbI assembly structures. Furthermore, the addition of benzenesulfonic acid increases the supersaturation threshold and the solubility of PbI in a high-temperature reaction system, and controls effectively the lead-iodine octahedron monomer concentration in the second nucleation stage. As a result, the as-synthesized CsPbI-S NCs exhibited different assembly morphologies and high PLQYs, among which the role of sulfonate groups can be further verified by UV absorption and surface characteristics. The strategy provides a new frontier to rationally control the surface ligand-induced self-assembly structures of perovskites.
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http://dx.doi.org/10.1039/d2nr06208a | DOI Listing |
J Phys Condens Matter
October 2024
Centro de Investigación en Ciencias, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, 62209 Cuernavaca, Morelos, Mexico.
All-inorganic perovskite quantum dots with the usual cubic shape have emerged as a successful and low-cost alternative to electronically functional nanomaterials motivating various fields of applications, including high-efficiency photovoltaics. Here, we present an efficient and almost analytic approach for optical absorption coefficient calculation on self-assembled perovskite quantum dot films with type-II band alignment. The approach takes advantage of the special point technique for integration over the two-dimensional Brillouin zone, which minimizes the computational cost.
View Article and Find Full Text PDFSmall
November 2024
Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Republic of Korea.
Among the lead halide perovskite (LHP) family, CsPbI is known to be significantly vulnerable to moisture, which hinders its use in real device applications. It is reported that chalcogen-based ligands can better stabilize CsPbI and revive nanocrystals (NCs). Here, diphenyl diselenide (DPhDSe) ligand is used to revive the degraded CsPbI NCs through a post-synthetic treatment of adding a small amount of DPhDSe in the degraded NC dispersion.
View Article and Find Full Text PDFJ Am Chem Soc
July 2024
Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States.
A triplet-triplet annihilation-based upconversion (TTA-UC) system, employing a multichromophore assembly, is convenient to harvest low-energy photons for light energy conversion and optoelectronic applications. The primary donor in the TTA-UC system, typically a low-bandgap semiconductor, captures the low-energy photons and transfers triplet energy to an annihilator dye molecule, which in turn generates a high-energy singlet excited state via T-T annihilation. We have now succeeded in revealing kinetic and mechanistic details of multistep energy transfer processes in the CsPbI-rubrene-perylene derivative (DBP) films by analyzing time-resolved emission and absorption measurements.
View Article and Find Full Text PDFSmall
September 2024
Institute of New Energy Technology, College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou, 510632, China.
Despite CsPbIBr inorganic perovskites exhibit high potential for single-junction and/or tandem solar cells, unexpected non-radiative recombination, and mismatched interfacial band alignment within the inorganic perovskite solar cells (PSCs) disadvantageously affect their photovoltaic performance. Rational design of the dipole shielding layer (DSL) is vital to realize a win-win situation for the defect passivation and band alignment. Herein, A-site dipole molecules, that is, neopentylamine and 2-methylbutylamine, are employed for in-situ self-assembly of a thus-far unreported DSL at the interface between 3D perovskite and hole transport layer.
View Article and Find Full Text PDFDalton Trans
April 2024
Department of Physics, Indian Institute of Technology Gandhinagar, Palaj 382355, India.
We present a facile and versatile strategy for enabling CsPbI rods to self-assemble at an air-water interface. The CsPbI rods, which float at the air-water interface, align under the influence of the rotational flow field due to the vortex motion of a water subphase. The aligned CsPbI rods could be transferred onto various substrates without involving any sophisticated instrumentation.
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