be achieved at relatively lower fi elds. [ 3 ] However, this would require the design and the synthesis of new dielectric materials with higher relative permittivity and very low dielectric losses. In addition, because the energy density is proportional to E 2 , it would benefi t by charging the capacitor with as high of an electric fi eld as possible.Another approach, then, would be to use materials with higher barrier heights or electrodes with carefully selected work functions to minimize or retard the tunneling current, so that high energy densities, by charging the capacitors at high fi elds, can be achieved, without increasing the leakage current or reducing the effi ciency. But, again, this would require synthesis of new materials.We propose a novel approach to achieve higher energy densities by re-engineering the architecture of capacitors. Our new capacitor device is a layered structure that incorporates thin electron and hole blocking layers deposited between the conducting electrodes and the dielectric material as schematically illustrated in Figure 1 . [ 4 ] The purpose of these blocking layers is to achieve an "effective" increase in barrier height that will minimize or delay tunneling current until extremely high electric fi elds are reached, without the need to develop new dielectric materials. To explain our concept, let us fi rst restate Zhang and co-workers' observations in terms of the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) levels. [ 3 ] Applying a positive bias voltage to the electron side of the capacitor raises the work function of the conducting electrode on the electron side, W fe . This reduces the energy gap ( E g ) between W fe and the LUMO level of the capacitor dielectric, thus reducing the barrier height. The higher the applied voltage, the smaller the E g , which in turn increases the fl ow of electrons over the barrier height or LUMO level of the capacitor dielectric. The insertion of an electron blocking layer (EBL), between the electrode and the dielectric fi lm, with a higher LUMO level than the capacitor dielectric ( Figures 1 and 2 ), Electrostatic capacitors offer high power density, lower loss, and higher operating voltage than their electrolytic and supercapacitor counterparts. However, these capacitors suffer from the low energy density (<2 J cm −3 ), limiting their applications in high power integrated systems such as pulsed power and high frequency inverters.In an electrostatic capacitor, the energy stored is in the form of an energy density in an electric fi eld. [ 1,2 ] Consequently, for linear dielectrics under an electric fi eld (dielectric constant independent of the applied fi eld), the stored energy density is linearly proportional to the dielectric constant ( ε ) and quadratically proportional to the applied electric fi eld ( E ). The level of the electric fi eld that can be applied, short of the catastrophic electrical failure (dielectric fi eld strength) of the material, may depend on either the inherent pro...

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Deoxyribonucleic acid (DNA) based hybrid films incorporating sol-gel-derived ceramics have shown strong promise as insulating dielectrics for high voltage capacitor applications. Our studies of DNA-CTMA (cetyltrimethylammonium) complex/sol-gel ceramic hybrid thin film devices have demonstrated reproducibility and stability in temperature- and frequency-dependent dielectric properties with dielectric constant k ∼ 5.0 (1 kHz), as well as reliability in DC voltage breakdown measurements, attaining values consistently in the range of 300–350 V/μm. The electrical/dielectric characteristics of DNA-CTMA films with sol-gel-derived ceramics were examined to determine the critical energy storage parameters such as voltage breakdown and dielectric constant.

This paper is a review of the recent research in bio-based materials for photonics and electronics applications. Materials that we have been working with include: deoxyribonucleic acid (DNA)-based biopolymers and nucleobases. We will highlight work on increasing the ionic conductivity of DNA-based membranes, enhancing the direct (DC) current and photoconductivity of DNA-based biopolymers, crosslinking of DNA-based biopolymers and promising applications for DNA nucleobases.

Hybrid films incorporating high dielectric constant k ceramics (BaTiO3 and TiO2) in deoxyribonucleic acid (DNA) were fabricated from highly stable dispersions of the ceramic nanoparticles in viscous, aqueous DNA solutions. Dielectric and electrical properties of the as-prepared nanocomposite films were investigated for potential use as gate insulators in organic field effect transistors. A k value as high as 14 was achieved with a 40 wt. % loading of ceramic nanoparticles in DNA. Electrical resistivities on the order of 1014 Ω cm with leakage current densities on the order of 10−9 A/cm2 were measured from current-voltage experiments under electric field biases up to 50 V/μm.