Research output: Contribution to journal › Article › peer-review
Separation and Recombination of Photocarriers from Color Centers and Optically Silent Trap States from 100 to 450 K: The Halide Double Photochromic Perovskite Cs2AgBiBr6. / Kuznetsov , Vyacheslav N. ; Glazkova, Nadezhda I. ; Mikhaylov, Ruslan V. ; Sharaf, Ibrahim M. ; Ryabchuk, Vladimir K. ; Emeline, Alexei V. ; Serpone, Nick.
In: ACS applied materials & interfaces, Vol. 13, No. 21, 02.06.2021, p. 25513-25522.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Separation and Recombination of Photocarriers from Color Centers and Optically Silent Trap States from 100 to 450 K: The Halide Double Photochromic Perovskite Cs2AgBiBr6
AU - Kuznetsov , Vyacheslav N.
AU - Glazkova, Nadezhda I.
AU - Mikhaylov, Ruslan V.
AU - Sharaf, Ibrahim M.
AU - Ryabchuk, Vladimir K.
AU - Emeline, Alexei V.
AU - Serpone, Nick
N1 - Publisher Copyright: © 2021 American Chemical Society. All rights reserved.
PY - 2021/6/2
Y1 - 2021/6/2
N2 - Compared to lead-based solar cells whose power conversion efficiency is 25.2%, the highest power conversion efficiency of a halide double Cs2AgBiBr6-based perovskite solar cell is less than 3%. It was therefore relevant to unravel the inherent reason(s) for such a low efficiency in the latter that may be related to trapping/detrapping of photocarriers. Accordingly, photocoloration and photobleaching phenomena occurring in the Cs2AgBiBr6 photochromic perovskite were examined from 100 to 450 K by diffuse reflectance spectroscopy (DRS). The separation and recombination of photogenerated charge carriers implicated both color centers and optically silent trap states within the bandgap. The processes were reversible subsequent to heating after illumination at 100 K but were mostly irreversible at 290 K. DRS spectral and kinetic measurements at T = 100–450 K were carried out after visible light illumination that further revealed the nature of the various charge carrier traps in Cs2AgBiBr6. Results confirmed the separation of photogenerated electrons and holes, with formation of the color centers identified as deep electron traps. Three different photoinduced color centers were responsible for the absorption bands observed at 1.78 (ab1), 1.39 (ab2), and 1.10 eV (ab3) at 100 K. Annealing of these electron-type color centers occurred in the temperature range of 100–450 K via recombination with holes in the valence band following their thermal release from the several hole traps. Application of a first-order kinetic model to the thermoprogrammed annealing (TPA) of the color centers’ spectra yielded estimates of the activation energies of hole detrapping and lifetimes of trapped holes at room temperature. The irreversibility of photocoloration at 290 K was caused by the formation of new deep hole trap states.
AB - Compared to lead-based solar cells whose power conversion efficiency is 25.2%, the highest power conversion efficiency of a halide double Cs2AgBiBr6-based perovskite solar cell is less than 3%. It was therefore relevant to unravel the inherent reason(s) for such a low efficiency in the latter that may be related to trapping/detrapping of photocarriers. Accordingly, photocoloration and photobleaching phenomena occurring in the Cs2AgBiBr6 photochromic perovskite were examined from 100 to 450 K by diffuse reflectance spectroscopy (DRS). The separation and recombination of photogenerated charge carriers implicated both color centers and optically silent trap states within the bandgap. The processes were reversible subsequent to heating after illumination at 100 K but were mostly irreversible at 290 K. DRS spectral and kinetic measurements at T = 100–450 K were carried out after visible light illumination that further revealed the nature of the various charge carrier traps in Cs2AgBiBr6. Results confirmed the separation of photogenerated electrons and holes, with formation of the color centers identified as deep electron traps. Three different photoinduced color centers were responsible for the absorption bands observed at 1.78 (ab1), 1.39 (ab2), and 1.10 eV (ab3) at 100 K. Annealing of these electron-type color centers occurred in the temperature range of 100–450 K via recombination with holes in the valence band following their thermal release from the several hole traps. Application of a first-order kinetic model to the thermoprogrammed annealing (TPA) of the color centers’ spectra yielded estimates of the activation energies of hole detrapping and lifetimes of trapped holes at room temperature. The irreversibility of photocoloration at 290 K was caused by the formation of new deep hole trap states.
KW - diffuse reflectance spectroscopy
KW - halide double perovskite
KW - photocoloration
KW - photobleaching
KW - separation of photocarriers
KW - halide double perovskite
KW - photocoloration
KW - Photobleaching
KW - separation of photocarriers
KW - diffuse reflectance spectroscopy
KW - photobleaching
KW - GAP METAL-OXIDES
KW - SPECTRAL DEPENDENCIES
KW - CSPBBR3
KW - PHOTOCHEMICAL PROCESSES
KW - CHARGE-CARRIER DYNAMICS
KW - QUANTUM YIELD
KW - SURFACE
UR - http://www.scopus.com/inward/record.url?scp=85107710925&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c03721
DO - 10.1021/acsami.1c03721
M3 - Article
VL - 13
SP - 25513
EP - 25522
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 21
ER -
ID: 77896407