Applications of Quantum Computing for Investigations of Electronic Transitions in Phenylsulfonyl-carbazole TADF Emitters

TL;DR

This study demonstrates the use of quantum algorithms to accurately predict electronic excited states of TADF emitters, showing promising agreement with experimental data and highlighting quantum computing's potential in molecular chemistry.

Contribution

It applies quantum algorithms like qEOM-VQE and VQD to simulate excited states of TADF molecules, achieving high accuracy without and with error mitigation.

Findings

Quantum simulations closely match experimental energy differences.

Error mitigation significantly improves energy prediction accuracy.

Quantum algorithms can effectively model excited states of complex molecules.

Abstract

A quantum chemistry study of the first singlet (S1) and triplet (T1) excited states of phenylsulfonyl-carbazole compounds, proposed as useful thermally activated delayed fluorescence (TADF) emitters for organic light emitting diode (OLED) applications, was performed with the quantum Equation-Of-Motion Variational Quantum Eigensolver (qEOM-VQE) and Variational Quantum Deflation (VQD) algorithms on quantum simulators and devices. These quantum simulations were performed with double zeta quality basis sets on an active space comprising the highest occupied and lowest unoccupied molecular orbitals (HOMO, LUMO) of the TADF molecules. The differences in energy separations between S1 and T1 ($\Delta E_{st}$) predicted by calculations on quantum simulators were found to be in excellent agreement with experimental data. Differences of 16 and 88 mHa with respect to exact energies were found for excited states by using the qEOM-VQE and VQD algorithms, respectively, to perform simulations on quantum devices without error mitigation. By utilizing error mitigation by state tomography to purify the quantum states and correct energy values, the large errors found for unmitigated results could be improved to differences of, at most, 3 mHa with respect to exact values. Consequently, excellent agreement could be found between values of $\Delta E_{st}$ predicted by quantum simulations and those found in experiments.