Phenothiazine-Phenoxazine Hybrid Cross Hole-Transporting Material for High Performance Perovskite Solar Cell

Area of Science:

• Materials Science
• Photovoltaics
• Organic Electronics

Background:

• Hole transport materials (HTMs) are crucial for perovskite solar cell (PSC) performance, impacting hole transport, electron recombination, and perovskite layer stability.
• Existing HTMs face challenges in achieving high efficiency and long-term stability in PSCs.

Purpose of the Study:

• To design and synthesize novel HTMs with diphenothiazine (D-PTZ) and diphenoxazine (D-POZ) core architectures for enhanced PSC performance.
• To investigate the synergistic effects of a hybrid phenothiazine-phenoxazine (PTZ-POZ) structure on HTM properties and PSC efficiency.

Main Methods:

• Synthesis of novel D-PTZ, D-POZ, and PTZ-POZ based HTMs.
• Characterization of HTM properties including solubility, film uniformity, and hole mobility.
• Fabrication and testing of small-area (0.0625 cm²) and large-area (1.0 cm²) PSCs using the developed HTMs.
• Assessment of PSC performance metrics such as power conversion efficiency (PCE) and hysteresis.
• Evaluation of long-term operational stability under controlled humidity and temperature conditions.

Main Results:

• The hybrid PTZ-POZ HTM demonstrated superior solubility, film uniformity, and hole mobility compared to D-PTZ and D-POZ.
• Small-area PSCs with PTZ-POZ achieved a record PCE of 25.85% with negligible hysteresis, outperforming D-PTZ (23.09%) and D-POZ (14.33%).
• Large-area PSCs (1.0 cm²) using PTZ-POZ reached a high PCE of 23.23%.
• The PTZ-POZ HTM exhibited excellent stability, retaining 90.4% of its initial PCE after 1080 hours of operation under 40%-50% humidity at ambient temperature.

Conclusions:

• The PTZ-POZ hybrid structure effectively synergizes the advantages of D-PTZ and D-POZ, leading to significant improvements in PSC performance.
• This study presents a novel molecular design strategy for developing high-efficiency, stable, and potentially low-cost HTMs for perovskite solar cells.
• The developed HTMs show great promise for the commercialization of efficient and durable perovskite solar technology.