Title: Ultrafast exciton many-body interactions and hot-phonon bottleneck in colloidal cesium lead halide perovskite nanocrystals

Abstract

Defect-tolerant perovskite nanocrystals of the general formula Cs-Pb-X₃ (where X=Cl, Br, and I) have shown exceptional potential in fundamental physics as well as in novel optoelectronic applications as the next generation of solar cells. Although exciton many-body interactions such as biexciton Stark shift, state filling, and Auger recombination are studied extensively, other important correlated effects, such as band gap renormalization (BGR) and hot-phonon bottleneck, are not explored in these nanocrystals. Here we experimentally demonstrate the carrier density dependence of the BGR and an effective hot-phonon bottleneck in CsPb(Cl_0.20Br_0.80)₃ mixed-halide nanocrystals. The results are compared with two other halide compositions, namely, CsPbBr₃ and CsPb(Br_0.55I_0.45)₃ nanocrystals with varying band gaps. The optical response of the nanocrystals changes dramatically across the spectral range of many hundreds of meV at high carrier density due to large BGR. We have calculated the BGR constant ~(6.0+/-0.3) x 10^-8eV cm for CsPb(Cl_0.20Br_0.80)₃ nanocrystals that provides the amount of band gap shift as a function of carrier density. In these nanocrystals, an efficient hot-phonon bottleneck is observed at a carrier density of 3.1 x 10¹⁷cm^-3 that slows down the thermalization by 1 order of magnitude. Our findings reveal that the complex kinetic profile of the exciton dynamics canmore » be analyzed by the global target analysis using the sequential model with increasing lifetimes.« less

Authors:

Mondal, Anirban ^[1]; Aneesh, J. ^[1]; Kumar Ravi, Vikash ^[2]; Sharma, Rituraj ^[1]; Mir, Wasim J. ^[2]; Beard, Mathew C. ^[3]; Nag, Angshuman ^[2]; Adarsh, K. V. ^[1]

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+ Show Author Affiliations

1. Indian Inst. of Science Education and Research, Bhopal (India)
2. Indian Inst. of Science Education and Research, Pune (India)
3. National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:

Mon Sep 10 00:00:00 EDT 2018

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Hybrid Organic-Inorganic Semiconductors for Energy (CHOISE); National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1476250

Alternate Identifier(s):

OSTI ID: 1469258

Report Number(s):

NREL/JA-5900-72530
Journal ID: ISSN 2469-9950; PRBMDO

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 98; Journal Issue: 11; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

14 SOLAR ENERGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; excitons; ultrafast phenomena