Predicting Energy Conversion Efficiency of Dye Solar Cells from First Principles

Abstract

In this work we target on accurately predicting energy conversion efficiency of dye-sensitized solar cells (DSC) using parameter-free first principles simulations. We present a set of algorithms, mostly based on solo first principles calculations within the framework of density functional theory, to accurately calculate key properties in energy conversion including sunlight absorption, electron injection, electron−hole recombination, open circuit voltages, and so on. We choose two series of donor-πacceptor dyes with detailed experimental photovoltaic data as prototype examples to show how these algorithms work. Key parameters experimentally measured for DSC devices can be nicely reproduced by first-principles with as less empirical inputs as possible. For instance, short circuit current of model dyes can be well reproduced by precisely calculating their absorption spectra and charge separation/recombination rates. Open circuit voltages are evaluated through interface band offsets, namely, the difference between the Fermi level of electrons in TiO 2 and the redox potential of the electrolyte, after modification with empirical formulas. In these procedures the critical photoelectron injection and recombination dynamics are calculated by realtime excited state electronic dynamics simulations. Estimated solar cell efficiency reproduces corresponding experimental values, with errors usually below 1−2%. Device characteristics such as light harvesting efficiency, incident photon-to-electron conversion efficiency, and the current−voltage characteristics can also be well reproduced and compared with experiment. Thus, we develop a systematic ab initio approach to predict solar cell efficiency and photovoltaic performance of DSC, which enables large-scale efficient dye screening and optimization through high-throughput first principles calculations with only a few parameters taken from experimental settings for electrode and electrolyte toward a renewable energy based society.

Density functional investigation and some optical experiments on dye-sensitized quantum dots

“…Our calculated V oc is in the range 2.3 -2.9 V (Table 6). To obtain an idea of the V oc values generally obtained, we note that the V oc for the thin film solar cells such as dye-sensitized solar cells [71][72][73] (in the cases where they have been calculated) or the experimental energy gap between the absorber and the acceptor 71,72,76 . This discrepancy is due to factors such as mismatch between energy levels, recombination losses, measuring method limitations and others.…”

Comparing Electron Recombination via Interfacial Modifications in Dye-Sensitized Solar Cells

“…1,3 These back reactions or electron recombination processes limit the performance of DSSCs. 3,4,5 Therefore, engineering and controlling these interfaces are critical to the development of efficient DSSCs.…”

How does the silicon element perform in JD-dyes: a theoretical investigation

“…It was reported by formed, is more stable in energy for the adsorbed dye than the bidentate-bridging (BB) configuration. 20,21 In the present work, many attempts have been made to find such a stable TB configuration but failed. Therefore, the dye/(TiO 2 ) 38 complexes with the BB configurations were employed in the following investigations.…”