An Effective Approach for High‐Efficiency Photoelectrochemical Solar Cells by Using Bifunctional DNA Molecules Modified Photoanode

Abstract

wileyonlinelibrary.comadsorption and relatively high recombination rate via vacant sites that significantly restrict the photoconversion efficiency (PCE). Therefore, researchers are faced with the challenge of developing efficient suppression routes by designing this component with an efficient charge transport pathway. Although some approaches were reported to suppress the charge recombinations occurring at the TiO 2 /dye interface including the use of inorganic [3,4] as well as polymer-assisted materials, [5][6][7] there are still some practical limitations due to the poor light absorption, low surface area, and slow electron injection. To overcome these limitations, extensive research efforts are directed toward DSSC applications of functionalized photoanode electrodes with novel interface modifiers and toward the design of solar cells. An appropriate interface modifier can play the role of assisting charge separation and also effectively shield the unfavorable reactions which occur from the injected electrons in photoanode's conduction band (CB) to the I 3 − ions in electrolyte and/or to the holes in highest occupied molecular orbital (HOMO) level of the dye. [8] Among modifier layers, thin tunneling barrier (TTB) at TiO 2 /dye interface is one of the most efficient and feasible ways, because TTB material is preferred in such a way that its CB is more positive than that of TiO 2 to form an energy barrier which allows electron injection but hinders the recombination reactions as well as passivate the surface states known as the vacant sites.Since then, many groups have attempted to modify photoanode in this system using alternative materials. [5,9,10] However, it has still not been reached to the desired PCE due to lower electron transport efficiency and sensitizing ability, much faster recombination, and difficult bind with TiO 2 or dyes. Alternative to these molecules, deoxyribonucleic acid (DNA) molecules have attracted research interest as modifier and/or linker because of cost effectiveness/easy fabrication, absorption ability in UV region causing high intersystem quantum yield, and favorable energy levels (HOMO: −5.2 eV; LUMO: −1.1 eV) [11][12][13] to inject charge, its 3D double helix structure confines the entered photons, and these photons snatch electrons after each collision with DNA molecules. This double helix structure is also beneficial for sunlight utilization from all directions. [14] This paper firstly reports the effect of deoxyribonucleic acid (DNA) molecules extracted from chickpea and wheat plants on the injection/recombination of photogenerated electrons and sensitizing ability of dye-sensitized solar cells (DSSCs). These high-yield DNA molecules are applied as both linker bridging unit as well as thin tunneling barrier (TTB) at titanium dioxide (TiO 2 )/dye interface, to build up high-efficient DSSCs. With its favorable energy levels, effective linker bridging role, and double helix structure, bifunctional DNA modifier shows an efficient electron injection, suppressed charge recombinati...

Enhanced Charge Separation Efficiency in DNA Templated Polymer Solar Cells

“…These elongated structures, with an average lateral distance of 1–6 nm, contain several DNA strands. Furthermore, Sönmezoğlu et al have reported highly efficient dye‐sensitized solar cells with a DNA modified ITO photoanode, in which the double‐helix of the DNA acts as linker bridging unit between the active layer and the ITO. Thus we postulate that when the P3HT polymer is spin coated on our ITO/ZnO‐NPs/DNA, the elongated strands of DNA chemically interact with the polymer strands leading to a more ordered layer as the solvent evaporates.…”

Merging Biology and Photovoltaics: How Nature Helps Sun‐Catching

“…Concerning electrodes/substrates the materials and approaches developed in OSCs have been also applied to DSSCs. [160][161][162] More innovative ideas toward bio-based dyes and electrolytes are present in the prior art. In short, the design of dyes for highly performing DSSCs should fulfill several requirements: i) high molar extinction coefficient, ii) broadband absorption spectra covering visible and Near-IR range, iii) strong binding or electron coupling with the mesoporous semiconductor, iv) alignment of energy levels, with regard to the conduction band of the semiconductor and the redox couple potential, and v) stability upon continuous sunlight exposition.…”

Enhancing the Sensitivity of Photoelectrochemical DNA Biosensing Using Plasmonic DNA Barcodes and Differential Signal Readout

“…Therefore, the observed reduction in R ct in this work can also occur due to the amine‐modified ssDNA covalently bonding with the aldehyde groups on the 3,4‐dihydroxybenzlaldehyde (DHBA) linker on the TiO 2 NP surface having the same linker chemistry as dopamine, thereby enhancing the probability of quantum tunneling. It has also been hypothesized that DNA functionalization reduces carrier trapping sites by passivating the semiconductor (TiO 2 ) surface, thereby reducing charge recombination [47] . In order to further validate this finding, we performed a study by performing cyclic voltammetry (CV) in 0.1 M phosphate buffer (PBS) to show changes in charge transfer kinetics (Supporting Figure S3).…”

“…Forschungsartikel linker chemistry as dopamine,t hereby enhancing the probability of quantum tunneling.I th as also been hypothesized that DNAf unctionalization reduces carrier trapping sites by passivating the semiconductor (TiO 2 )surface,thereby reducing charge recombination. [47] In order to further validate this finding,w ep erformed as tudy by performing cyclic voltammetry (CV) in 0.1 Mphosphate buffer (PBS) to show changes in charge transfer kinetics (Supporting Figure S3). This study showed that the amount of stored charges in the photoelectrodes were increased from 0.59 mC to 0.72 mC after DNAf unctionalization, indicating longer lived excitons.…”