Understanding radiation-generated electronic traps in radiation dosimeters based on organic field-effect transistors.

Organic dosimeters offer unique advantages over traditional technologies, and they can be used to expand the capabilities of current radiation detection systems. In-depth knowledge of the mechanisms underlying the interaction between radiation and organic materials is essential for their widespread adoption. Here, we identified and quantitatively characterized the electronic traps generated during the operation of radiation dosimeters based on organic field-effect transistors. Spectral analysis of the trap density of states, along with optical and structural studies, revealed the origin of trap states as local structural disorder within the crystalline films. Our results provide new insights into the radiation-induced defects in organic dosimeters, and pave the way for the development of more efficient and reliable radiation detection devices.

Measurement principles for quantum spectroscopy of molecular materials with entangled photons.

Nonlinear spectroscopy with quantum entangled photons is an emerging field of research that holds the promise to achieve superior signal-to-noise ratio and effectively isolate many-body interactions. Photon sources used for this purpose, however, lack the frequency tunability and spectral bandwidth demanded by contemporary molecular materials. Here, we present design strategies for efficient spontaneous parametric downconversion to generate biphoton states with adequate spectral bandwidth and at visible wavelengths. Importantly, we demonstrate, by suitable design of the nonlinear optical interaction, the scope to engineer the degree of spectral correlations between the photons of the pair. We also present an experimental methodology to effectively characterize such spectral correlations. Importantly, we believe that such a characterization tool can be effectively adapted as a spectroscopy platform to optically probe system-bath interactions in materials.