Biocompatible Flexible Hybrid Inorganic – Organic X-ray Detectors

Progress in radiotherapy has led to increased cancer patient survival rates. To achieve further improvements in patient survival rates, identifying the exact dose delivered to tumour sites and minimising damage to surrounding healthy tissue and organs, ideally through implantable dosimeters, is considered the next frontier. However, the lack of a low-cost, flexible, tissue-equivalent direct conversion semiconductor diode continues to impede further developments in this area. Compared to commercial solid-state detectors, hybrid inorganic-in-organic (IOH) detectors offer several benefits, such as biocompatibility, high sensitivity under clinically relevant X-ray energies, and lower cost of manufacture. This thesis addresses direct X-ray detection with ultrathin hybrids based on P3HT:PC70BM:Bi2O3 and P3HSe:PC70BM, translated from rigid platforms and ~55 µm flexible stacks to ~1 µm flexible stacks. The work discussed here integrates four elements: thickness down-scaling to ultrathin implantable dimensions of ~1 µm; understanding the in-vivo operando of ultrathin detectors under laboratory and clinical X-ray irradiation; pixel down scaling and integration of polyimide (PI) as a hole blocking layer, and clinical-beam validation under a 6 MV LINAC. On investigations related to the influence of thickness reduction, ultralow dark-current densities of