Titania as Buffer Layer for Cd-Free Kesterite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Kesterite (Cu2ZnSnS4) solar cells are promising due to cost-effectiveness and sustainability.
• Current kesterite devices are limited by toxic cadmium sulfide (CdS) buffer layers and suboptimal band alignment.
• Alternative buffer layers are needed to improve kesterite solar cell performance and environmental impact.

Purpose of the Study:

• To experimentally investigate titanium dioxide (TiO2) as a cadmium-free buffer layer for kesterite solar cells.
• To evaluate the performance of kesterite solar cells using ALD-TiO2 compared to conventional CdS buffer layers.
• To address the limited experimental data on TiO2/kesterite interfaces.

Main Methods:

• Fabrication of kesterite photovoltaic devices utilizing atomic layer deposition (ALD) of TiO2 as the buffer layer.
• Characterization of device performance, including power conversion efficiency.
• Comparison with reference kesterite solar cells employing CdS buffer layers.

Main Results:

• Preliminary experimental results demonstrate promising performance for kesterite solar cells with ALD-TiO2 buffer layers.
• Achieved efficiencies are comparable to those of kesterite solar cells using conventional CdS buffer layers.
• This study provides one of the few experimental validations of TiO2 as a viable buffer layer for kesterite photovoltaics.

Conclusions:

• Atomic layer deposition of TiO2 is a viable strategy for creating efficient, cadmium-free kesterite solar cells.
• TiO2 presents a promising alternative to CdS, potentially overcoming limitations associated with toxicity and band alignment.
• Further optimization of the TiO2 buffer layer could lead to enhanced kesterite solar cell efficiencies.