Solvent-induced orientation of FAPbI₃ single crystals for highly efficient self-powered X-ray detectors

Area of Science:

• Materials Science
• Solid-State Physics
• Device Engineering

Background:

• Perovskite materials offer potential for self-powered X-ray detectors.
• Device sensitivity is often limited by material defects.
• Controlling crystal orientation can mitigate perovskite defects.

Purpose of the Study:

• To co-develop (100), (110), and (111) crystal orientations in formamidinium lead iodide (FAPbI3) solar cells (SCs) for the first time.
• To investigate the impact of crystal orientation on FAPbI3 SC performance for X-ray detection.
• To achieve high-performance self-powered X-ray detectors using orientation-engineered perovskites.

Main Methods:

• Inducing specific crystal facets ((100), (110), (111)) by selecting solvents with low surface energy.
• Fabricating FAPbI3 SCs with dominant (100), (110), or (111) orientations.
• Evaluating device performance under visible-light and X-ray illumination.

Main Results:

• The (100)-oriented FAPbI3 SCs exhibited reduced trap-state density and suppressed ionic migration compared to (110) and (111) orientations.
• Improved charge collection in (100)-oriented devices led to superior response under both light and X-ray.
• A record sensitivity of ~5000 μC Gyair⁻¹ cm⁻² was achieved for self-powered X-ray detection using (100)-oriented FAPbI3 SCs with 30 keV X-rays.

Conclusions:

• Solvent-induced orientation engineering is a viable strategy to reduce defects in perovskites.
• The (100)-oriented FAPbI3 SCs demonstrate exceptional performance as self-powered X-ray detectors.
• This approach enables perovskite SCs to surpass existing technologies in X-ray detection sensitivity.