Thermal stress stabilized thick perovskite heterostructures for radiation detection

Abstract

Integrating lead halide perovskite onto the standard readout circuit substrate is the path to the commercialization of perovskite-based radiation detection and imaging. However, due to the large thermal expansion coefficient difference between perovskite and inorganic substrate, such heterostructure faces the challenge of thermal stress induced mechanical instability. This problem will be extremely severe for the thick perovskite film for radiation detection because the thermal strain energy accumulates with film thickness. Here, first by theoretical analysis, we quantized the thermal stress instability and found that a temperature variation of only 20 °C around room temperature will suffice to delaminate a 100 µm thick perovskite film from the substrate, which prediction agrees with experiments. We then proposed to promote the heterostructure's mechanical stability by increasing the perovskite nucleation rate on inorganic substrate to enhance the interface adhesive energy. Based on a sacrificial seeding layer, we realized stable interface between the thick perovskite film and the typical inorganic substrate, including indium tin oxide, silicon, and gallium nitride that can withstand at least 100 cycles of temperature variation between 25 and 150 °C and then fabricated high performance radiation detectors based on such heterostructures.