Hole-Induced Charge Transfer Dynamics at the CsPbBr3 Perovskite Quantum Dot Interface

In the quest to advance solar energy conversion, understanding the intricacies of charge transfer (CT) at interfaces has become crucial for photovoltaic applications. Efficient CT is essential for minimizing energy losses due to recombination and enhancing the efficiency of the devices. Herein, we delve into the significance of the CT process in the improvement of current conduction across the interface by using several spectroscopic and microscopic measurements. A photoinduced CT mechanism in CsPbBr3 perovskite quantum dots (PQDs) is explored with a band-aligned hole acceptor, anthracene. All of the spectroscopic measurements reveal a prominent CT from PQDs to anthracene through hole transfer, as evinced from the energy level diagram and density of states calculations. The electrical measurements across an electrode-semiconductor-electrode junction using conductive atomic force microscopy reflect an increase in the conductance in PQD after the introduction of anthracene. The inclusion of anthracene in the PQD changes the nature of the current-voltage curve from nonlinear to Ohmic one, revealing only direct tunneling and both direct and Fowler-Nordheim tunneling for PQD with and without anthracene, respectively. These findings can contribute to the development of efficient and cost-effective optoelectronic devices with a careful selection of simple molecules as charge transport or some additional layers.