# Perovskite-Graphene Energy Integrating Detector for X-Ray Imaging

> **NIH NIH R43** · KAIROS SENSORS LLC · 2021 · $246,965

## Abstract

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.

## Key facts

- **NIH application ID:** 10384524
- **Project number:** 1R43EB032694-01
- **Recipient organization:** KAIROS SENSORS LLC
- **Principal Investigator:** Kendon Robert Shirley
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $246,965
- **Award type:** 1
- **Project period:** 2021-09-30 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10384524

## Citation

> US National Institutes of Health, RePORTER application 10384524, Perovskite-Graphene Energy Integrating Detector for X-Ray Imaging (1R43EB032694-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10384524. Licensed CC0.

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