The n‐Silicon/Thallium(III) Oxide Heterojunction Photoelectrochemical Solar Cell

Abstract

Thallium(III) oxide is a degenerate n‐type semiconductor which can be electrochemically or photoelectrochemically deposited on conducting or semiconducting substrates. The material is highly conductive, transparent, and electrocatalytic. A photoelectrochemical cell consisting of the n‐silicon/thallium(III) oxide photoanode and a platinum cathode in an alkaline solution of the ferrocyanide/ferricyanide redox couple produced a 0.512V open‐circuit photovoltage, 33.5 mA/cm2 short‐circuit photocurrent density, 0.643 fill factor, and 13.8% photovoltaic efficiency with 80 mW/cm2 iR‐filtered xenon light. The efficiency was 11.0% with 75.3 mW/cm2 natural sunlight, and 22.3% with 800 nm monochromatic light. The short‐circuit quantum efficiency at 800 nm was 97%. A xenon photovoltaic efficiency of 10.2% was observed with cast multicrystalline n‐silicon. Photocurrent‐voltage curves were computer simulated using values of the barrier height (0.96V), diode quality factor (1.2), and series resistance (200Ω) that were measured from dark current voltage and capacitance‐voltage curves. A solid‐state photovoltaic cell was fabricated by making a low‐pressure point contact to the front surface of a dry photoanode. The photovoltaic characteristics of the solid‐state cell were nearly identical with those of the photoelectrochemical cell. These results suggest that the photoelectrochemical cell functions like a Schottky‐barrier or SIS solid‐state photovoltaic cell in series with a highly reversible electrochemical cell.

Protection of inorganic semiconductors for sustained, efficient photoelectrochemical water oxidation

“…[29] Generally, a tandem 5 structure or triple junction structure is necessary to produce sufficient voltage and current density for efficient water splitting [19,20,30]. In addition to use of semiconductor/liquid interfaces as the voltage-generating junction, buried-junction structures, including planar p-n homojunctions [31,32], semiconductor/metal Schottky barriers [33,34], spherical [35] and radialjunction microwire [36] electrodes, heterojunctions [37,38], metal-insulator-semiconductor contacts [9,15], and emitters derived from in situ inversion layers [21] have all been investigated for use in photoelectrosynthetic or photovoltaic-biased electrosynthetic cells [39]. The efficiencies and main performance characteristics of various reported solar-driven water-splitting systems have been recently compiled [40].…”

“…Metal oxide photoanodes are however generally limited by either low maximum photocurrent densities and/or instability in relevant media [8][9][10][11][12][13][14].…”

Epitaxial Electrodeposition of Chiral Films Using Chiral Precursors

“…In this process, the electrochemically produced species reacts with water or hydroxide ions to form a metal oxide on the electrode. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] A second method to produce thin films is to electrochemically change the pH of the electrolyte at the electrode surface. Because the solubility of any material is dependent on pH, the pH can be electrochemically changed at the electrode surface, thus lowering the solubility of the material and resulting in the precipitation of the material only on the electrode surface.…”

High-pressure structural and elastic properties of Tl2O3

“…6 In particular, it has been used as an electrode in high-efficiency solar cells due to its very low resistivity. 7,8 It has also been studied for optical communication applications because of its strong reflectance in the near infrared region (1300-1500 nm); 9 however, its most promising application is in thallium oxide-based high-temperature superconductors. 10 Despite its interesting technological applications, Tl 2 O 3 is one of the less studied sesquioxides probably because of the poisonous nature of thallium.…”