Charge-Transfer Dynamics of Fluorescent Dye-Sensitized Electrodes under Applied Biases.
The development of dye-sensitized solar cells requires an in-depth understanding of the interfacial charge-transfer dynamics that take place between dye sensitizers and semiconductors. Here, we describe a prototype system to probe these dynamics by monitoring in real time the fluorescence of two organic sensitizers, a perylene and a squaraine, bound to a SnO2 semiconductor thin film as a function of potentiostatic control of the Fermi level. The two different sensitizer fluorophores characterized by vastly different redox potentials undergo similar fluorescence modulation with applied bias, an indication that the density of states of the semiconductor largely influences the charge-transfer dynamics while energetics play a minimal role. We further show that the rate of photodegradation of the perylene sensitizer with applied bias provides a suitable marker to study the rate of charge injection and charge recombination. Taken together, our results demonstrate a suitable platform to visualize and study charge-transfer dynamics on films and constitute a step toward achieving single-molecule resolution in our quest to decipher the static and dynamic heterogeneity of charge-transfer dynamics in dye-sensitized photoanodes.
†Department of Chemistry and Center for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
Robert
R
Godin
§Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States.
Benjamin D
BD
Sherman
§Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States.
Jesse J
JJ
Bergkamp
‡Departamento de Quı́mica, Facultad de Ciencias Exactas Fı́sico-Quı́micas y Naturales, Universidad Nacional de Rı́o Cuarto, Rı́o Cuarto, Córdoba Argentina.
Carlos A
CA
Chesta
§Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States.
Ana L
AL
Moore
§Department of Chemistry and Biochemistry, Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States.
Thomas A
TA
Moore
‡Departamento de Quı́mica, Facultad de Ciencias Exactas Fı́sico-Quı́micas y Naturales, Universidad Nacional de Rı́o Cuarto, Rı́o Cuarto, Córdoba Argentina.
Rodrigo E
RE
Palacios
†Department of Chemistry and Center for Self-Assembled Chemical Structures (CSACS/CRMAA), McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
Gonzalo
G
Cosa
dye-sensitized solar cells; interdacial charge-transfer dynamics; perylene; squaraine