Perovskite-Graphene Energy Integrating Detector for X-Ray Imaging

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Approximately 12% of women have a false-positive result after one mammogram, and 60% have a false positive after ten yearly mammograms - resulting in the need for secondary screenings. The cost of unnecessary secondary screenings, often due to the inability to differentiate between healthy and unhealthy tissue with the desired accuracy, has been calculated to be $4 billion per year. Increasing the sensitivity of low exposure per frame X-ray detectors will reduce the need for unnecessary secondary screenings and improve patient outcomes via enhanced image quality. Image quality largely depends on the response of the detector's sensor to X-rays, aka sensitivity. Sensitivity is dependent on the sensor's ability to generate as many X-ray liberated charge carriers as possible that will contribute towards the signal acquisition for an image. Sometimes this is referred to as the sensor's average ionization energy or internal gain. Direct conversion sensors (semiconductors), such as amorphous selenium (a-Se), have a low internal gain – making low exposure per frame applications like tomosynthesis challenging to generate signals above the noise of the electronics. Recently, new materials such as organic/inorganic metal halide perovskites have drawn attention for their considerable stopping power of X-rays, efficient charge transfer properties, and ease of material synthesis. Additionally, graphene materials are known for their photoconductive gain and comfort of integration with conventional electronic platforms. Kairos Sensors LLC proposes a multi-pixel perovskite-graphene energy integrating detector for X-ray imaging with vastly improved sensitivity and low power consumption for this Phase I proposal. Kairos Sensors' innovation utilizes solution-processed perovskites grown directly from the conductive graphene lattice and has shown ultra-high sensitivity with prototype single-pixel perovskite-graphene devices. This project aims to achieve a multi-pixel perovskite-graphene detector with high sensitivity via optimized configuration of material composition and pixel dimensions. Phase I will focus on demonstrating an extremely sensitive multi-pixel perovskite-graphene detector. Phase II will focus on a more extensive pixel array and take images in preparation for commercialization.