Related Experiment Video
Updated: Jul 11, 2025

In situ Grazing Incidence Small Angle X-ray Scattering on Roll-To-Roll Coating of Organic Solar Cells with Laboratory X-ray Instrumentation
Published on: March 2, 2021
BiVO4-Liquid Junction Photovoltaic Cell with 0.2% Solar Energy Conversion Efficiency
Sahar Daemi1, Samhita Kaushik2, Soumik Das2
1Department of Chemistry, University of California, Davis, California 95616, United States.
Bismuth vanadate (BiVO4) photoanodes demonstrate photovoltaic effects with a triiodide/iodide electrolyte, achieving 0.55 V photovoltage. Mo doping enhances conductivity but lowers photovoltage in these novel BiVO4-liquid photovoltaic cells.
Area of Science:
- Materials Science
- Electrochemistry
- Photovoltaics
Background:
- Bismuth vanadate (BiVO4) is a key photoanode material for water oxidation.
- Its photoelectrochemical behavior with the triiodide/iodide redox couple remains poorly understood.
- Understanding these interfaces is crucial for developing efficient photoelectrochemical devices.
Purpose of the Study:
- To investigate the photoelectrochemistry of BiVO4 with the triiodide/iodide redox couple.
- To construct and analyze BiVO4-based liquid photovoltaic cells.
- To evaluate the impact of Molybdenum (Mo) doping on device performance.
Main Methods:
- Open circuit potential measurements.
- Photoelectrochemical scans.
- Liquid surface photovoltage spectroscopy (SPS).
- Fabrication of FTO/BiVO4/KI(I2)aq/Pt sandwich cells.
Main Results:
- BiVO4/triiodide/iodide interfaces generated up to 0.55 V photovoltage.
- Constructed cells achieved up to 0.22% energy conversion efficiency, 0.32 V photovoltage, and 1.8 mA cm-2 photocurrent.
- Mo doping improved conductivity and incident photon-to-current efficiency but reduced photovoltage due to defects and Schottky junctions.
Conclusions:
- This study presents the first BiVO4-liquid photovoltaic cell, elucidating its operational principles and limitations.
- Hole transfer to iodide is rapid, suppressing water oxidation.
- Photovoltage losses stem from band edge misalignment, electron back transfer, and Mo-induced defects.
Related Concept Videos
Voltaic/Galvanic Cells
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
P-N junction
Photoelectric Effect
Schottky Barrier Diode
Biasing of P-N Junction
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
Metal-Semiconductor Junctions
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...

