Dodecahedron CsPbBr₃ Perovskite Nanocrystals Enable Facile Harvesting of Hot Electrons and Holes

Abstract

This Letter reports the facile harvesting of hot carriers (HCs) in a composite of 12-faceted dodecahedron CsPbBr 3 nanocrystal (NC) and a scavenger molecule. We recorded ∼3.3 × 10 11 s −1 HC cooling rate in NC when excited with ∼1.4 times the band gap energy (E g ), increasing to >3 × 10 12 s −1 in the presence of scavengers at high concentration due to the HC extractions. Since the observed intrinsic charge transfer rate (∼1.7 × 10 12 s −1 ) in our NC− scavenger complex is about an order of magnitude higher than the HC cooling rate (∼3.3 × 10 11 s −1 ), carriers are harvested before their cooling. Further, a fluorescence correlation spectroscopy study reveals NC tends to form a quasi-stable complex with a scavenger molecule, ensuring charge transfer completed (τ ct ≈ 0.6 ps) much before the complex breaks apart (>600 μs). The overall results of our study highlight the promise shown by 12-faceted NCs and their implications in modern applications, including hot carrier solar cells.

Electron Transfer from an Optically Pumped Polyhedral Perovskite Nanocrystal to Pristine Fullerene

“…The HRTEM image confirms the dodecahedron morphology of our PNCs, resembling previous reports. ,− The inset shows the particle size distribution, with an average edge length of ∼18 nm (Figure A). Powder XRD patterns depicted in Figure B reveal the presence of (112) and (200) facets, matching nicely with PDF reference lines for the orthorhombic phase (PDF-01-072-7929) and the previous reports. ,, Steady-state PL and UV–vis spectra of our 12-faceted PNCs exhibit peaks at ∼518 and ∼510 nm (first excitonic), respectively; both are slightly red-shifted compared to ones (∼515 and ∼504 nm) reported for cubic counterparts of similar size (Figure C). ,, …”

“…Powder XRD patterns depicted in Figure 1B reveal the presence of ( 112) and (200) facets, matching nicely with PDF reference lines for the orthorhombic phase (PDF-01-072-7929) and the previous reports. 1,20,21 Steady-state PL and UV−vis spectra of our 12-faceted PNCs exhibit peaks at ∼518 and ∼510 nm (first excitonic), respectively; both are slightly red-shifted compared to ones (∼515 and ∼504 nm) reported for cubic counterparts of similar size (Figure 1C). 1,22,23 Instruments Used.…”

“…Interference from solvent diffusion often complicates the solution phase PET study. However, the present study involves PNC–fullerene complex formation, as confirmed by the fluorescence correlation spectroscopy (FCS) study, where the observed PET time scale at high quencher concentration is purely intrinsic. − …”

Numerical Simulation of Highly Efficient Cs2TiI6 based Pb Free Perovskites Solar Cell with the Help of Optimized ETL and HTL Using SCAPS-1D Software

“…Despite these advancements in the next generation of solar cells, stability continues to be a major obstacle to industrial application and commercialization. When the first thin film-based third generation Perovskite solar cells were created, they contained an organic-inorganic compound with the chemical formula 𝐴𝐵𝑋 3 , where 𝑋 is an anion and may be one of the halide elements 𝐵𝑟, 𝐼, 𝐶𝑙, or 𝐹, and 𝐴 and 𝐵 are cations [9]. Anion position has a significant impact on how energy is produced.…”

“…In turn, this leads to increased power conversion efficiency (PCE, %). Kojima was the first to introduce such a hybrid halide with 𝐶𝐻 3 𝑁𝐻 3 𝑃𝑏𝐼 3 and 𝐶𝐻 3 𝑁𝐻 3 𝑃𝑏𝐵𝑟 3 as the active components for solar cells, and PCE was up to 3.8% [9].…”