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Jerry Icban Dadap

Publications and source records attributed to Jerry Icban Dadap.

2 recordsLinked to original sources

Isolating Exciton Dissociation Pathways in ReSe$_{\text{2}}$

Strongly bound excitons dominate the optical response in many van der Waals semiconductors, yet distinguishing between the different microscopic processes governing exciton dissociation remains challenging. Using time- and angle-resolved photoemission spectroscopy (TR-ARPES), we independently track exciton and band-edge carrier populations in bulk ReSe$_{\text{2}}$ under resonant excitation. By studying the fluence dependence and polarization-controlled exciton density dependence of the exciton dissociation process, we distinguish between competing processes and identify exciton photoionization as the microscopic dissociation mechanism. These results establish a population-resolved strategy for resolving exciton-to-carrier conversion pathways in strongly excitonic materials.

cond-mat.mtrl-sci↗

Quenching of excitons at grain boundaries in C60 thin films

Exciton lifetimes play a critical role in the performance of organic optoelectronic devices. In this work, we investigate how the presence of multiple rotational domains, and therefore grain boundaries, impacts exciton dynamics in thin films of C60/Au(111) using time and angle-resolved photoemission spectroscopy (TR-ARPES). We find that films with multiple rotational domains exhibit shorter exciton lifetimes and evidence of exciton-exciton annihilation, even when one domain predominates. Scanning tunneling microscopy (STM) measurements reveal electronic structure changes resulting from a locally reduced dielectric constant at grain boundaries, providing a mechanism for lifetime reduction through exciton funneling and other additional decay channels. These findings highlight the critical role of film quality in determining intrinsic exciton lifetimes, and show that minuscule amounts of disorder that are nearly undetectable by ensemble measurements can significantly impact dynamics. These results imply that precise structural control is essential for optimize the performance of organic optoelectronic devices.

cond-mat.mtrl-sci↗