Conjugated N-Type Diradical Semiconductor Empowers High-Performance TiO₂-Based Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Semiconductor Physics

Background:

• Titanium dioxide (TiO2) is crucial for perovskite solar cells (PSCs) but suffers from efficiency limitations due to surface defects and low conductivity.
• Tin dioxide (SnO2)-based PSCs currently outperform TiO2 counterparts, highlighting the need for TiO2 improvement.

Purpose of the Study:

• To develop a novel interface engineering strategy for TiO2 electron transport layers in PSCs.
• To introduce a n-type conjugated diradical semiconductor, IDT-R, for defect passivation and conductivity enhancement of TiO2.
• To investigate the impact of IDT-R on the performance and stability of PSCs.

Main Methods:

• Synthesis and characterization of the novel n-type conjugated diradical semiconductor, IDT-R.
• Deposition of IDT-R onto TiO2 layers for interface modification in PSCs.
• Fabrication and testing of PSC devices incorporating the modified TiO2 electron transport layer.

Main Results:

• IDT-R effectively passivates surface defects on TiO2 and enhances its intrinsic conductivity.
• The synergistic effect of IDT-R improves electron extraction and transport at the buried interface.
• PSCs utilizing IDT-R modified TiO2 achieved a high power conversion efficiency (PCE) of 25.38% with enhanced thermal stability.

Conclusions:

• The novel n-type diradical semiconductor IDT-R offers a promising approach for interface engineering in PSCs.
• Modulating the electrical properties of TiO2 through IDT-R significantly enhances device performance and stability.
• This work pioneers the use of n-type diradical semiconductors for electron-selective contacts in PSCs.