Bipyridine-Based One-Dimensional Perovskites with Type-II Band Alignment Enables High-Sensitivity Direct X-ray...

Area of Science:

• Materials Science
• Solid-State Physics
• Detector Technology

Background:

• Low-dimensional hybrid perovskites are promising for X-ray detection due to stability.
• Performance is often hindered by inefficient charge carrier transport.

Purpose of the Study:

• Synthesize and evaluate novel 1D lead iodide perovskites for direct X-ray detection.
• Investigate the structure-property relationships influencing carrier transport and device performance.

Main Methods:

• Synthesis of 1D lead iodide perovskites (44DPPbI4 and 22DP2Pb3I10) using specific organic cations.
• Density Functional Theory (DFT) calculations to analyze electronic band structures and charge separation.
• Fabrication and characterization of X-ray detector devices.

Main Results:

• Both materials exhibit type-II band alignment, facilitating charge separation and reducing recombination.
• 44DPPbI4 shows a favorable energy offset for interfacial charge separation, enhancing carrier mobility-lifetime product.
• The 44DPPbI4 device achieved high sensitivity (5631.81 μC Gy-1 cm-2) and a low detection limit (4.40 nGy s-1).
• Both perovskites demonstrated high ionic activation energies and resistivity, indicating suppressed ion migration.

Conclusions:

• The designed 1D perovskites offer enhanced environmental stability and suppressed ion migration.
• 44DPPbI4 presents a viable material for high-performance direct X-ray detection.
• This work introduces a new material design strategy for advanced X-ray detector development.