Open AccessFormamidinium Halide Perovskite and Carbon Nitride Thin Films Enhance Photoreactivity under Visible Light Excitation
Author(s) -
Gopi Ragupathy,
J.G. Riess,
BatEl Cohen,
Lioz Etgar,
Roey Sagi,
Kumar P. Deepak,
Reinhard Schomäcker,
Micha Asscher
Publication year - 2022
Publication title -
the journal of physical chemistry. a/the journal of physical chemistry. a.
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 235
eISSN - 1520-5215
pISSN - 1089-5639
DOI - 10.1021/acs.jpca.2c02565
Subject(s) - formamidinium , chemistry , photochemistry , photoluminescence , perovskite (structure) , substrate (aquarium) , visible spectrum , halide , materials science , inorganic chemistry , optoelectronics , organic chemistry , oceanography , geology
Photochemical and photocatalytic activity of adsorbates on surfaces is strongly dependent on the nature of a given substrate and its resonant absorption of the (visible) light excitation. An observation is reported here of the visible light photochemical response of formamidinium lead bromide (FAPbBr 3 ) halide perovskite and carbon nitride (CN) thin-film materials (deposited on a SiO 2 /Si(100) substrate), both of which are known for their photovoltaic and photocatalytic properties. The goal of this study was to investigate the role of the substrate in the photochemical reactivity of an identical probe molecule, ethyl chloride (EC), when excited by pulsed 532 nm laser under ultrahigh vacuum (UHV) conditions. Postirradiation temperature-programmed desorption (TPD) measurements have indicated that the C-Cl bond dissociates following the visible light excitation to form surface-bound fragments that react upon surface heating to form primarily ethane and butane. Temperature-dependent photoluminescence (PL) spectra of the FAPbBr 3 films were recorded and decay lifetimes were measured, revealing a correlation between length of PL decay and the photoreactivity yield. We conclude that the FAPbBr 3 material with its absorption spectrum in resonance with visible light excitation (532 nm) and longer PL lifetime leads to three times faster (larger cross-section) photoproduct formation compared with that on the CN substrate. These results contrast the behavior under ambient conditions where the CN materials are photochemically superior due, primarily, to their stability within humid environments.