Hot Hole Transfer Dynamics from CsPbBr₃ Perovskite Nanocrystals

Abstract

Transfer of the hot charge carriers prior to their cooling to the band-edge states can enhance the efficiency of a semiconductor-based solar cell much beyond its Shockley–Queisser (SQ) limiting value. Herein, we explore transfer of hot holes from the APbBr3 nanocrystals (NCs) employing a carefully chosen molecular system, 4-mercaptophenol. Ultrafast pump–probe and fluorescence measurements indeed confirm this transfer process, whose efficiency depends on the energy content of the hole, and a maximum efficiency of ∼43% is achieved with CsPbBr3 NCs for a photoexcitation energy of ∼1.46E g (E g is the band gap of the NCs). While the estimated hot hole cooling and transfer rates are quite comparable, hole transfer from the band edge is found to be a significantly slower process. The findings of the present study suggest that exceeding the SQ efficiency of the solar cells based on the perovskites can indeed be a reality.

State of the Art and Prospects for Halide Perovskite Nanocrystals

“…Extraction of hot charge carriers is a challenging task due to their rapid relaxation to the band-edge states. Only a few reports of HC extraction from perovskites are so far available. ,,,− In an early work, transfer of hot electron and hot hole from CsPbBr 3 NCs to BQ and PTZ was established by monitoring the photoinduced change in conductivity in time-resolved THz transmission . Li et al showed transfer of hot electrons from MAPbBr 3 to 4,7-diphenyl-1,10-phenanthroline (Bphen) from the sharp drop in bleach amplitude at early time in the presence of the latter.…”

Room‐Temperature Treatment with Thioacetamide Yielding Blue‐ and Green‐Emitting CsPbX3 Perovskite Nanocrystals with Enhanced Photoluminescence Efficiency and Stability

“…Further details about the setup can be found elsewhere. [51] Fourier transformed infrared spectroscopy (FTIR): FTIR measurements were performed using Bruker Tensor II spectrometer. Single drop of colloidal solution of as-synthesized and treated CsPbBr 3 NCs was used from the stock solution (in hexane).…”

Anthraquinone-Enriched Conjugated Microporous Polymers as Organic Cathode Materials for High-Performance Lithium-Ion Batteries

“…Solar cells, fuel cells, and rechargeable batteries have become fundamental tools for energy storage, with lithium-ion batteries (LIBs) having gained great popularity because of their low ecological footprint, high energy density, and good cycle life. Nevertheless, LIBs have major drawbacks, including their carbon anodes having a theoretical capacity of only 372 mAh g –1 , which must be addressed. − At present, lithium batteries often contain poisonous metals, which bring into consideration huge energy utilization and climate contamination, particularly for bulk energy storage applications. − Although industrially used LIBs have electrodes of inorganic origin, these materials are hazardous and scarce, leading to sustainability issues . The advancement of organic cathode materials for battery-powered applications has been moderate in comparison with that of inorganic cathode materials. − Organic materials have unique advantages when used as cathode materials, including facile molecular engineering, , low cost, high abundance, environmental friendliness, and high theoretical capacities .…”

“…5−7 Although industrially used LIBs have electrodes of inorganic origin, these materials are hazardous and scarce, leading to sustainability issues. 8 The advancement of organic cathode materials for battery-powered applications has been moderate in comparison with that of inorganic cathode materials. 9−11 Organic materials have unique advantages when used as cathode materials, including facile molecular engineering, 2,12 low cost, high abundance, environmental friendliness, and high theoretical capacities.…”