biostudies-literatureUeda AMinistry of Education, Culture, Sports, Science and TechnologyJapan Society for the Promotion of Science18353-18358https://www.ebi.ac.uk/biostudies/studies/S-EPMC9064737biostudies-literatureUnknown9(32)Purely organic crystals, κ-X₃(Cat-EDT-TTF)₂ [X = H or D, Cat-EDT-TTF = catechol-fused tetrathiafulvalene], are a new type of molecular conductor with hydrogen dynamics. In this work, hydrostatic pressure effects on these materials were investigated in terms of the electrical resistivity and crystal structure. The results indicate that the pressure induces and promotes hydrogen (deuterium) localization in the hydrogen bond, in contrast to the case of the conventional hydrogen-bonded materials (where pressure prevents hydrogen localization), and consequently leads to a significant change in the electrical conducting properties (<i>i</i>.<i>e</i>., the occurrence of a semiconductor-insulator transition). Therefore, we have successfully found a new type of pressure-induceRSC advancesPressure-induced hydrogen localization coupled to a semiconductor-insulator transition in a hydrogen-bonded molecular conductor.PMC906473717H0514318H05516JP18H05516JP17H051432434007416H04010JP19K0539716K05744Murakami YGouchi JUeda AKamo HKumai RKishimoto KUwatoko YYamada SMori HNishio YIsono TKobayashi KfalsePressure-induced hydrogen localization coupled to a semiconductor-insulator transition in a hydrogen-bonded molecular conductor.Purely organic crystals, κ-X₃(Cat-EDT-TTF)₂ [X = H or D, Cat-EDT-TTF = catechol-fused tetrathiafulvalene], are a new type of molecular conductor with hydrogen dynamics. In this work, hydrostatic pressure effects on these materials were investigated in terms of the electrical resistivity and crystal structure. The results indicate that the pressure induces and promotes hydrogen (deuterium) localization in the hydrogen bond, in contrast to the case of the conventional hydrogen-bonded materials (where pressure prevents hydrogen localization), and consequently leads to a significant change in the electrical conducting properties (<i>i</i>.<i>e</i>., the occurrence of a semiconductor-insulator transition). Therefore, we have successfully found a new type of pressure-induce2019-01-01T00:00:00Z2019 Jun2025-04-18T14:13:50.13Z2025-04-04T20:21:59.506ZS-EPMC90647373551523410.1039/c9ra02833a