Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine

Thai Hoang Nguyen, Ha Minh, Torben Lund

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

The kinetics of the thiocyanate substitution of the solar cell sensitizer [Ru(Hdcbpy)B2B(NCS)B2B]P2-P, 2 (n-CB4BHB9B)B4BNP+)P, (HB2Bdcbpy = L = 2,2´-bipyridine-4,4´-dicarboxylic acid), known as N719, by acetonitrile, 3-methoxypropionitrile, and 4-tert-butylpyridine (4-TBP) have been determined in both homogenous solutions and colloidal mixtures of N719-dyed TiO2 nanocrystalline particles. Thiocyanate ligand substitution by the solvents (S) acetonitrile or 3-methoxypropionitrile in homogeneous solutions occurs at elevated temperatures (80-110°C) by means of a simple slow pseudo-first-order reaction leading to the formation of the product [RuL2(NCS)(S)]+ with a half life time t1/2  ~ 2000 h of N719 at 80 ºC. If tert-butylpyridine (0.5 M) is added, the end product instead becomes [RuL2(NCS)(4-TBP)]+  with a t1/2 ~1000 h. When N719 is bound to TiO2 particles, the reactions with S and 4-TBP give the same products as occur in the homogenous solutions; however, the reactions are approximately 10 times faster. For the reaction of a colloidal mixture of N719-dyed TiO2 particles in acetonitrile containing 0.5 M 4-TBP, a t1/2(het) of 120 h was calculated at 85°C. The N719-based DSSC cells with acetonitrile and 4-TBP as solvent and additive are therefore not expected to be able to pass a 1000-h thermal stress test in the dark at 85°C due to thermal degradation of the N719 dye. Adding guanidine thiocyanate to the colloidal solutions, however, decreased the rate of [RuL2(NCS)(4-TBP)]+ formation by a factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells.
OriginalsprogEngelsk
TidsskriftSolar Energy Materials & Solar Cells
Vol/bind91
Udgave nummer20
Sider (fra-til)1934-1942
Antal sider9
ISSN0927-0248
DOI
StatusUdgivet - 2007

Citer dette

@article{8e7c2f90cf3211dcaf2a000ea68e967b,
title = "Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine",
abstract = "The kinetics of the thiocyanate substitution of the solar cell sensitizer [Ru(Hdcbpy)B2B(NCS)B2B]P2-P, 2 (n-CB4BHB9B)B4BNP+)P, (HB2Bdcbpy = L = 2,2´-bipyridine-4,4´-dicarboxylic acid), known as N719, by acetonitrile, 3-methoxypropionitrile, and 4-tert-butylpyridine (4-TBP) have been determined in both homogenous solutions and colloidal mixtures of N719-dyed TiO2 nanocrystalline particles. Thiocyanate ligand substitution by the solvents (S) acetonitrile or 3-methoxypropionitrile in homogeneous solutions occurs at elevated temperatures (80-110°C) by means of a simple slow pseudo-first-order reaction leading to the formation of the product [RuL2(NCS)(S)]+ with a half life time t1/2  ~ 2000 h of N719 at 80 ºC. If tert-butylpyridine (0.5 M) is added, the end product instead becomes [RuL2(NCS)(4-TBP)]+  with a t1/2 ~1000 h. When N719 is bound to TiO2 particles, the reactions with S and 4-TBP give the same products as occur in the homogenous solutions; however, the reactions are approximately 10 times faster. For the reaction of a colloidal mixture of N719-dyed TiO2 particles in acetonitrile containing 0.5 M 4-TBP, a t1/2(het) of 120 h was calculated at 85°C. The N719-based DSSC cells with acetonitrile and 4-TBP as solvent and additive are therefore not expected to be able to pass a 1000-h thermal stress test in the dark at 85°C due to thermal degradation of the N719 dye. Adding guanidine thiocyanate to the colloidal solutions, however, decreased the rate of [RuL2(NCS)(4-TBP)]+ formation by a factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells.",
keywords = "N719, Degradation, LC-MS, Tert-butylpyridine",
author = "Nguyen, {Thai Hoang} and Ha Minh and Torben Lund",
year = "2007",
doi = "10.1016/j.solmat.2007.07.011",
language = "English",
volume = "91",
pages = "1934--1942",
journal = "Solar Energy Materials & Solar Cells",
issn = "0927-0248",
publisher = "Elsevier BV * North-Holland",
number = "20",

}

Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine. / Nguyen, Thai Hoang; Minh, Ha; Lund, Torben.

I: Solar Energy Materials & Solar Cells, Bind 91, Nr. 20, 2007, s. 1934-1942.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine

AU - Nguyen, Thai Hoang

AU - Minh, Ha

AU - Lund, Torben

PY - 2007

Y1 - 2007

N2 - The kinetics of the thiocyanate substitution of the solar cell sensitizer [Ru(Hdcbpy)B2B(NCS)B2B]P2-P, 2 (n-CB4BHB9B)B4BNP+)P, (HB2Bdcbpy = L = 2,2´-bipyridine-4,4´-dicarboxylic acid), known as N719, by acetonitrile, 3-methoxypropionitrile, and 4-tert-butylpyridine (4-TBP) have been determined in both homogenous solutions and colloidal mixtures of N719-dyed TiO2 nanocrystalline particles. Thiocyanate ligand substitution by the solvents (S) acetonitrile or 3-methoxypropionitrile in homogeneous solutions occurs at elevated temperatures (80-110°C) by means of a simple slow pseudo-first-order reaction leading to the formation of the product [RuL2(NCS)(S)]+ with a half life time t1/2  ~ 2000 h of N719 at 80 ºC. If tert-butylpyridine (0.5 M) is added, the end product instead becomes [RuL2(NCS)(4-TBP)]+  with a t1/2 ~1000 h. When N719 is bound to TiO2 particles, the reactions with S and 4-TBP give the same products as occur in the homogenous solutions; however, the reactions are approximately 10 times faster. For the reaction of a colloidal mixture of N719-dyed TiO2 particles in acetonitrile containing 0.5 M 4-TBP, a t1/2(het) of 120 h was calculated at 85°C. The N719-based DSSC cells with acetonitrile and 4-TBP as solvent and additive are therefore not expected to be able to pass a 1000-h thermal stress test in the dark at 85°C due to thermal degradation of the N719 dye. Adding guanidine thiocyanate to the colloidal solutions, however, decreased the rate of [RuL2(NCS)(4-TBP)]+ formation by a factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells.

AB - The kinetics of the thiocyanate substitution of the solar cell sensitizer [Ru(Hdcbpy)B2B(NCS)B2B]P2-P, 2 (n-CB4BHB9B)B4BNP+)P, (HB2Bdcbpy = L = 2,2´-bipyridine-4,4´-dicarboxylic acid), known as N719, by acetonitrile, 3-methoxypropionitrile, and 4-tert-butylpyridine (4-TBP) have been determined in both homogenous solutions and colloidal mixtures of N719-dyed TiO2 nanocrystalline particles. Thiocyanate ligand substitution by the solvents (S) acetonitrile or 3-methoxypropionitrile in homogeneous solutions occurs at elevated temperatures (80-110°C) by means of a simple slow pseudo-first-order reaction leading to the formation of the product [RuL2(NCS)(S)]+ with a half life time t1/2  ~ 2000 h of N719 at 80 ºC. If tert-butylpyridine (0.5 M) is added, the end product instead becomes [RuL2(NCS)(4-TBP)]+  with a t1/2 ~1000 h. When N719 is bound to TiO2 particles, the reactions with S and 4-TBP give the same products as occur in the homogenous solutions; however, the reactions are approximately 10 times faster. For the reaction of a colloidal mixture of N719-dyed TiO2 particles in acetonitrile containing 0.5 M 4-TBP, a t1/2(het) of 120 h was calculated at 85°C. The N719-based DSSC cells with acetonitrile and 4-TBP as solvent and additive are therefore not expected to be able to pass a 1000-h thermal stress test in the dark at 85°C due to thermal degradation of the N719 dye. Adding guanidine thiocyanate to the colloidal solutions, however, decreased the rate of [RuL2(NCS)(4-TBP)]+ formation by a factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells.

KW - N719

KW - Degradation

KW - LC-MS

KW - Tert-butylpyridine

U2 - 10.1016/j.solmat.2007.07.011

DO - 10.1016/j.solmat.2007.07.011

M3 - Journal article

VL - 91

SP - 1934

EP - 1942

JO - Solar Energy Materials & Solar Cells

JF - Solar Energy Materials & Solar Cells

SN - 0927-0248

IS - 20

ER -