Hot Hole Cooling and Transfer Dynamics from Lead Halide Perovskite Nanocrystals Using Porphyrin Molecules

Abstract

A deep understanding of hot carrier (HC) dynamics is important to improve the performance of optoelectronic devices by reducing the thermalization losses. Here, we investigate the hot hole cooling and transfer dynamics of CsPbBr 3 nanocrystals (NCs) using 5,10,15,20-tetra(4pyridyl) porphyrin (TpyP) molecules. Density functional theory (DFT) is used to elucidate the mechanism underlying charge extraction as well as the HC transfer process in the CsPbBr 3 −TpyP system. It is noted that the hot hole states are localized around the top surface of CsPbBr 3 , while the hot electron states are delocalized away from its top surface, indicating easy extraction of hot holes from the CsPbBr 3 by TpyP molecules, as compared to the hot electrons. The significant drop of initial hot carrier temperature from 1140 to 638 K at 400 nm excitation confirms the hot hole transfer from CsPbBr 3 NCs to TpyP molecules, which is dependent on the excitation energy, and the maximum transfer efficiency is found to be 42% (for 0.85 eV above band edge photoexcitation). In addition, the hot hole transfer rate is almost 11 times faster than the band edge hole transfer rate. Our findings are relevant for the development of next-generation perovskite-based optoelectronic devices.

Impacts of CsPbBr3/PbSe Heterostructures on Carrier Cooling Dynamics at Low Carrier Density

“…It can be approximated to Maxwell–Boltzmann (MB) distribution for excess energy of HC greater than quasi‐Fermi energy ( E F ). Thus, as soon as HC reaches the quasi‐equilibrium state, T C is extracted by fitting the high energy tail of the GSB signal with the following MB distribution function: [ 24,31,32,54 ] where ΔT stands for the amplitude of bleach at a particular probe wavelength, E F is the quasi‐Fermi energy level, K B is the Boltzmann constant, and T C is the HC temperature (see supplementary note 3 for detailed fitting procedure). We extracted T C from the TA spectra after 400 fs time delay to ensure a quasi‐equilibrium state has been reached by HCs, after the initial fs‐pulse excitation.…”

“…It can be approximated to Maxwell-Boltzmann (MB) distribution for excess energy of HC greater www.advopticalmat.de than quasi-Fermi energy (E F ). Thus, as soon as HC reaches the quasi-equilibrium state, T C is extracted by fitting the high energy tail of the GSB signal with the following MB distribution function: [24,31,32,54] ω ω ( )…”

Structural Analysis and Carrier Relaxation Dynamics of 2D CsPbBr3 Nanoplatelets

“…25,26 Therefore, a deep understanding of hot carrier cooling, carrier dynamics, and charge transfer of 2D CsPbBr 3 NPLs is relevant in recent times for overcoming the Shockley−Queisser (SQ) limit to enhance solar cell's efficiency. 27,28 Theoretical calculations predict that solar cell efficiency can go up to 67% after utilizing the excess energy of hot carriers. 29 From the carrier cooling dynamics of the 2D colloidal NPLs study, it is evident that hot electron cooling depends on temperature.…”

Colloidal Sb3+-Doped Cs2InCl5·H2O Perovskite Nanocrystals with Temperature-Dependent Luminescence

“…Both microcrystals and colloidal NCs of lead halide perovskites show interesting optoelectronic properties. − But lead toxicity is a concern . Various bivalent (Sn 2+ , Ge 2+ , Zn 2+ ), , trivalent (Bi 3+ , Sb 3+ , In 3+ ), − monovalent (Cu + ), or a combination of mono- and trivalent (Na + , K + , Ag + , Bi 3+ , Sb 3+ , In 3+ ) − cations have been used as a replacement of lead.…”