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Fundamental Carrier Lifetime Exceeding 1 µs in Cs2AgBiBr6 Double Perovskite

Published version
Peer-reviewed

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Authors

Eyre, L 
Wei, F 
Brivio, F 
Sadhanala, A 

Abstract

jats:titleAbstract</jats:title>jats:pThere is current interest in finding nontoxic alternatives to lead‐halide perovskites for optoelectronic applications. Silver–bismuth double perovskites have recently gained attention, but evaluating their carrier lifetime and recombination mechanisms from photoluminescence measurements is challenging due to their indirect bandgap. In this work, transient absorption spectroscopy is used to directly track the photocarrier population in Csjats:sub2</jats:sub>AgBiBrjats:sub6</jats:sub> by measuring the ground state bleach dynamics. A small initial drop is resolved in the ground state bleach on a picosecond timescale, after which the remaining photocarriers decay monoexponentially with a lifetime of 1.4 µs. The majority of the early‐time decay is attributed to hot‐carrier thermalization from the direct transition to the indirect bandgap, and the 1.4 µs lifetime represents the recombination of most photocarriers. From this lifetime, a steady‐state excess carrier density of 2.2 × 10jats:sup16</jats:sup> cmjats:sup−3</jats:sup> under 1 sun is calculated, which is an order of magnitude larger than that for methylammonium lead iodide, suggesting that charge transport and extraction can be efficient in Csjats:sub2</jats:sub>AgBiBrjats:sub6</jats:sub> solar cells.</jats:p>

Description

Keywords

defect recombination, double perovskite, lifetime, time-resolved photoluminescence, transient absorption spectroscopy

Journal Title

Advanced Materials Interfaces

Conference Name

Journal ISSN

2196-7350
2196-7350

Volume Title

5

Publisher

Wiley
Sponsorship
Engineering and Physical Sciences Research Council (EP/M005143/1)
EPSRC (via Brunel University London) (unknown)
Engineering and Physical Sciences Research Council (EP/L015978/1)
EPSRC (EP/L015978/1, EP/L000202/1, EP/M005143/1, EP/L0011700/1) Magdalene College, Cambridge Indo-UK APEX Project UKIERI Isaac Newton Trust (Minute 13.38(k)) Herchel Smith Trust Winton Programme for the Physics of Sustainability