Tuning the Ultrafast Dynamics of Photoinduced Proton-Coupled Electron Transfer in Energy Conversion Processes

Abstract

Photoinduced proton-coupled electron transfer (PCET) is essential for a wide range of energy conversion processes in chemical and biological systems. Understanding the underlying principles of photoinduced PCET at a level that allows tuning and control of the ultrafast dynamics is crucial for designing renewable and sustainable energy sources such as artificial photosynthesis devices and photoelectrochemical cells. This Perspective discusses fundamental aspects of photoinduced PCET, including the characterization of different types of excited electronic states, as well as the roles of solute and solvent dynamics, nonadiabatic transitions, proton delocalization, and vibrational relaxation. It also presents strategies for tuning and controlling the charge transfer dynamics and relaxation processes by altering the nature and positions of molecular substituents, the distance associated with electron transfer, the proton transfer interface, and the solvent properties. These insights, in conjunction with further studies, will play an important role in guiding the design of more effective energy conversion devices.

Investigating photoinduced proton coupled electron transfer reaction using quasi diabatic dynamics propagation

“…Photoinduced proton-coupled electron transfer (PI-PCET) reactions [1][2][3] involve the coupled transfer of both electron and proton upon photoexcitation. Thus, PI-PCET is fundamentally different from the extensively studied photoinduced proton transfer (PT) or electron transfer (ET) reactions.…”

“…3,13 At the same time, they are promising for providing new and unique reactivities which are not directly accessible in regular thermally activated PCET reactions. 2,3 Thus, understanding the fundamental mechanistic principles of PI-PCET will allow tuning and controlling this reaction and provide design principles for more efficient solar energy conversion devices.…”

Deciphering the incognito role of water in a light driven proton coupled electron transfer process

“… 2 Photosystem II is a beacon that represents the significance of the PCET process, and it is prevalent in various vital enzymatic reactions, 1 , 3 catalytic oxidation, 1 , 4 the production of molecular hydrogen, 5 artificial photosystems 6 and most chemical and biological energy conserving reactions. Hence, exploring various factors that influenc the PCET process and its energetics, 7 , 8 dynamics 9 – 15 and mechanistic pathways 1 , 11 , 16 – 19 is necessary to design an efficient artificial photosystem which can harness solar energy in chemical bonds for the growing global energy need.…”

Direct Non-adiabatic Simulations of the Photoinduced Charge Transfer Dynamics

“…[8][9][10][11][12][13][14][15] Examples include PICT in dye-sensitized solar cells, [8][9][10][11][15][16][17] ultra-fast charge-transfer in organic photovoltaic systems, [12][13][14]18,[18][19][20][21][22][23][24][25] photocatalytic electron/hole transfer in "colloidal quantum dot-organic molecule complex" interfaces, [26][27][28] and photoinduced proton-coupled electron transfer. [29][30][31] Understanding the detailed charge transfer dynamics will provide valuable mechanistic insights and design principles for next-generation photocatalytic devices, and profoundly impact energy production and catalysis.…”