# Diphosphane-Mediated Control of the Emissive Properties in [Cu(NHC)(P^P)]+ Complexes: TADF vs Phosphorescence

## TL;DR

This paper explores how diphosphane structures affect the light-emitting properties of copper complexes, offering new ways to design efficient TADF emitters.

## Contribution

The study identifies the diphosphane skeleton as the key factor in controlling quantum yields in TADF-phosphorescent emitters.

## Key findings

- Optimizing diphosphane structures can increase quantum yields up to 85%.
- The diphosphane skeleton has a stronger influence on quantum yield than energy gaps or steric factors.
- Ligand engineering offers new pathways for high-performance TADF emitters.

## Abstract

The influence of both the
skeleton and substituents of the diphosphane
in the photophysical properties of [Cu­(NHC)­(P^P)]­PF6 TADF-phosphorescent
emitters is investigated [NHC = Bz-Im-2-XPy (X = H, Cl)]. The study
reveals that optimization of the diphosphane structure can boost quantum
yields to as high as 85% using carbenes with simple structural frameworks
or substituent wings. Remarkably, the diphosphane skeleton emerges
as the most influential factor for controlling the quantum yield (Φ).
None of the ΔE­(S1-T1) energy gap, steric
factors (buried volume percentage), or T1 energy alone
seem to govern the observed Φ. These insights reveal new avenues
for achieving high-performance TADF emitters through ligand engineering.