Tailoring the Mesoscopic TiO₂ Layer: Concomitant Parameters for Enabling High-Performance Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Mesoporous titanium dioxide (TiO2) films are crucial electron-transport layers in organic-inorganic hybrid perovskite solar cells.
• Controlling the architecture of the TiO2 layer impacts device performance by influencing light absorption and charge transport.

Purpose of the Study:

• To investigate the effect of architectural control over mesoporous TiO2 films on perovskite solar cell performance.
• To explore the use of sub-micron sized polystyrene beads as sacrificial templates for TiO2 film fabrication.

Main Methods:

• Employing sub-micron sized polystyrene beads as sacrificial templates to create tailored mesoporous TiO2 films.
• Fabricating perovskite solar cells with the templated TiO2 electron-transport layer.
• Analyzing device performance through photocurrent, power conversion efficiency, optical bandgap, haze transmission, and one-diode model parameters.

Main Results:

• The templated TiO2 layer induced asymmetric enhancement of light absorption, particularly in the long-wavelength region.
• A red-shifted absorption onset of perovskite was observed, leading to a ~20% increase in photocurrent.
• Power conversion efficiency increased by ~10% due to enlarged perovskite grains within the sub-micron pores and optimized hole-blocking.
• Further improvements of ~20% in power conversion efficiency were achieved by mitigating interfacial recombination through proper hole-blocking methods.

Conclusions:

• Structural engineering of the electron-transport layer is imperative for enhancing perovskite solar cell performance.
• Templating strategies offer a viable route to optimize TiO2 films for improved light harvesting and charge dynamics.
• Controlling perovskite grain morphology and minimizing interfacial recombination are key governing elements for high-efficiency devices.