A review of printable, flexible and tissue equivalent materials for ionizing radiation detection

Abstract

Advances in flexible and printable electronics have paved the way for large-area, and low-cost wearable electronics that will revolutionize the way we detect and monitor ionizing radiation. The improvements to early detection and widespread use of treatment procedures of tumors and other illnesses using ionizing radiation have led to the rapid increase in the yearly dose exposure to the public. Therefore, safety organizations must introduce stricter quality assurance measures to ensure the safe delivery of the total dose to the patient—only achievable using live monitoring systems, named in-vivo dosimetry. Such systems would also benefit the safety of professional personnel employed in areas that encounter higher exposures of ionizing radiation including nuclear plants, space exploration, flight staff, and research beamline facilities. However, the current real-time detectors employ expensive and rigid high-Z materials including silicon, germanium, and cadmium telluride, that suffer substantial limitations in monitoring the dose deposited in biological tissue and conforming to the complex contours of the human body over large areas. We provide insights into the innovative materials capable of solution-based device fabrication onto flexible substrates with foreseeable avenues towards low-cost large-area printing techniques. This discussion will also review and identify the advantages and existing capabilities of tissue-equivalent materials in the detection of ionizing radiation as the ideal materials for in-vivo dosimetry. Finally, the radiation tolerance of organic materials is outlined to demonstrate that extensive investigations are still required before their utilization as radiation detectors.

Recent progresses of organic photonic synaptic transistors

“…In conclusion, the three-terminal transistors have higher equipment stability than two-terminal devices, and compared with the electrical stimulation, the optical stimulation has the advantages of low interference and quick response, etc. At the same time, compared with the inorganic materials, the organic materials can be easily processed and have good flexibility [139,140]. Therefore, OPSTs are an attractive device for current research [141].…”

Toward Low-Voltage and High-Sensitivity Direct X-ray Detectors Based on Thick Bulk Heterojunction Organic Device

“…10 The response of organic materials to ionizing radiation closely mimics that of human tissues because they possess low densities (∼1 g cm −3 ) and main elemental compositions of hydrogen and carbon (low-Z elements), with small proportions of functional groups. 11 It is expected that they will be suitable for the complex calibration procedures of inorganic radiation detectors in medical applications and wearable electronics. 12,13 Recently, organic crystal materials with high mobility and micrometer thickness have been used for direct detectors.…”

“…Organic semiconducting materials are a highly attractive alternative for X-ray detection, offering the benefits of a semiconductor, such as almost instantaneous photon-to-electrical energy conversion combined with the chemical and mechanical benefits of plastic materials . The response of organic materials to ionizing radiation closely mimics that of human tissues because they possess low densities (∼1 g cm –3 ) and main elemental compositions of hydrogen and carbon (low-Z elements), with small proportions of functional groups . It is expected that they will be suitable for the complex calibration procedures of inorganic radiation detectors in medical applications and wearable electronics. , Recently, organic crystal materials with high mobility and micrometer thickness have been used for direct detectors. − An X-ray detector with 4-hydroxycyanobenzene (80 μm) had a sensitivity of 93 μC Gy air –1 cm –2 and an X-ray on/off ratio of 157 .…”

Halogenated Thermally Activated Delayed Fluorescence Materials for Efficient Scintillation

“…However, the high preparation temperature, scarce resources, and potential toxicity to the environment and human bodies of these materials may limit their practical applications. Metal-free organic scintillators have natural advantages such as milder preparation conditions, good mechanical flexibility, and large-area fabrication [ 19 , 21 , 22 ]. For this reason, metal-free organic scintillators are good candidates for scintillation.…”