High-performance direct conversion X-ray detectors based on sintered hybrid lead triiodide perovskite wafers

• Published in: Nature photonics Vol. 11; no. 7; pp. 436 - 440
• Main Authors: Shrestha, Shreetu, Fischer, René, Matt, Gebhard J., Feldner, Patrick, Michel, Thilo, Osvet, Andres, Levchuk, Ievgen, Merle, Benoit, Golkar, Saeedeh, Chen, Haiwei, Tedde, Sandro F., Schmidt, Oliver, Hock, Rainer, Rührig, Manfred, Göken, Mathias, Heiss, Wolfgang, Anton, Gisela, Brabec, Christoph J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2017; Nature Publishing Group
• Subjects: 147/135; 639/301; 639/301/1005/1009; Absorption cross sections; Ammonium; Applied and Technical Physics; Carrier mobility; Crystallinity; Direct conversion; Low temperature; Mobility; Physics; Quantum Physics; Sensors; Sintering; Temperature effects; Thick films; Wafers; X ray detectors
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/nphoton.2017.94

Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI 3 ) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI 3 wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 µC Gy air −1  cm −2 under 70 kV p X-ray exposure. The high ambipolar mobility–lifetime product of 2 × 10 −4  cm 2  V −1 is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafers. Methyl ammonium lead triiodide perovskite wafers for application in direct conversion X-ray detectors are fabricated by a room-temperature sintering process. A conversion efficiency of 2,527 mC Gy air cm –2 under 70 kVp X-ray exposure is obtained.