Black-Si as a Photoelectrode.

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Black silicon (b-Si) offers enhanced light absorption properties.
• Photoanodes are crucial components in photoelectrochemical cells for energy conversion.
• Titanium dioxide (TiO2) and cobalt oxide (CoOx) are common materials in catalysis and energy applications.

Purpose of the Study:

• To fabricate and characterize novel photoanodes utilizing black silicon (b-Si).
• To investigate the photoelectrochemical performance of a heterostructured b-Si/TiO2/CoOx system.
• To explore the role of the n-n junction between b-Si and TiO2 in device performance.

Main Methods:

• Fabrication of b-Si using maskless dry plasma etching.
• Conformal coating of TiO2 via atomic layer deposition (ALD).
• Deposition of CoOx cocatalyst using pulsed laser deposition (PLD).
• Characterization using a photoelectrochemical cell in NaOH solution.

Main Results:

• Achieved low reflectivity (R < 5%) for b-Si across visible and near-IR spectra, enhancing light absorption.
• Increased surface area of b-Si facilitated higher current densities.
• Demonstrated photoelectrochemical performance attributed to the n-n junction between b-Si and TiO2.

Conclusions:

• The fabricated b-Si-based photoanodes exhibit promising properties for light absorption and current generation.
• The heterostructure design, including TiO2 and CoOx, contributes to improved photoelectrochemical performance.
• Further research into the n-n junction is warranted for optimizing these photoanodes for solar energy applications.