Solar Cells Incorporating Water/Alcohol-Soluble Electron-Extracting DNA Nanolayers

Abstract

Deoxyribonucleic acid (DNA) was successfully incorporated as a nanolayer between the bottom indium tin oxide (ITO) transparent electrode and the photoabsorbing film in a polymer solar cell. Upon film optimization and analyses with scanning tunneling spectroscopy/currents, we demonstrate that a 1−6 nm thick DNA stratum functions as an effective electron-extracting layer, leading to strong improvements in rectifying behavior (by 2 orders of magnitude with rectifying ratios reached larger than 10 3 ) and in photovoltaic parameters like the open-circuit voltage (V OC from 0.39 to 0.73 V) and power conversion efficiencies (PCEs from ∼2 to ∼5%). The results show that DNA is a very ductile nanomaterial for electronic purposes, paving the way for future exploration in photovoltaic devices combining its electron-extracting properties with its functional and self-assembly behavior. Furthermore, solar cell devices were completely processed at room temperature, and DNA was cast from ecofriendly solvents such as water and alcohol.

Enhanced Charge Separation Efficiency in DNA Templated Polymer Solar Cells

“…The ZnO‐NPs thin film was deposited on ITO coated glass substrate by spin‐coating at spin speed of 2500 rpm which was carried out and then annealed at 140 °C for 20 min. The DNA solution was prepared first by dissolving 5 mg DNA fibers in 0.5 mL of deionized water until the solution becomes transparent and then 4.5 mL of methanol was added to dilute it to be 1 mg mL −1 concentration . After overnight stirring at room temperature, the DNA solution was filtered using a 0.2 µm Polyvinylidene fluoride (PVDF) filter (NB: it is important to use this type of filter to obtain the films discussed in this article; the use of PTFE or polypropylene filters with the same pore size instead, resulted in DNA films with different optical and thickness properties) and then spin‐coated on ITO coated glass substrate at spin speed of 3000 rpm over the ZnO‐NPs thin film.…”

“…DNA has been widely investigated as a potential template for the realization of different DNA‐templated layers or nanostructures as it is a readily available, well characterized, controllable and easily adaptable material . DNA and its derivatives have also been used to improve the performance of organic electronic devices including organic light emitting diodes, organic field effect transistors and organic polymer solar cells . Whereas the main explanation for the effects seen upon incorporation of DNA in these organic semiconductor devices has focused on the electronic properties of the contact, the effect of DNA on the morphology and order of the polymer has largely remained unexplored.…”

Advances in hole transport materials engineering for stable and efficient perovskite solar cells

“…Biologically derived materials have also been employed as transport layers in solar cells. Whereas in OPV, deoxyribose nucleic acid (DNA) in its "natural" Na salt form was successfully integrated as an ETL between ITO and the bulk heterojunction polymer active layer [181], in perovskite solar cells a DNA hexadecyl trimethyl ammonium chloride (CTMA) complex was used as HTM in an inverted p i n device configuration with PCBM as electron acceptor layer. The cells exhibited a PCE of~15.9% maintaining more than 85% of its initial value after 50 days in air [182].…”

Alkali Salts as Interface Modifiers in n‐i‐p Hybrid Perovskite Solar Cells

“…After impressive power conversion efficiencies (PCEs) of over 23% have been reached on lab‐scale small‐area (<1 cm 2 ) devices, the scalability and stability of PSCs are now among the most important technological challenges. Thin‐film PSCs with the perovskite absorber layer processed on top of an n‐type selective contact, such as zinc, titanium, indium, and tin oxide (ZnO, TiO 2 , InO 3 , and SnO 2 ), are among the most commonly used device architectures and referred to as “regular” or n‐i‐p devices. SnO 2 was realized as a better n‐type selective contact due to energetic match between SnO 2 and perovskite conduction bands and low temperature processing compared with TiO 2 ETL .…”