Covalent Functionalization of Black Phosphorus Quantum Dots and Characteristic Charge Transfer from Anthracene-passivated Black Phosphorus Nanospheres to C60 Pyrrolidine Tris-Acid

This study investigates interfacial charge transfer between organic and inorganic semiconductors, focusing on black phosphorus quantum dots (BPQDs) and anthracene-passivated black phosphorus nanospheres (A-BPNSs) as donors and C60 pyrrolidine tris-acid (CPTA) as the acceptor. Solvothermal method was employed for the QD synthesis along with their characterization, following various spectromicroscopic methods. The exciton dynamics of the donor–acceptor systems were probed by using steady-state and time-resolved photoluminescence spectroscopy. A-BPNSs exhibited a longer exciton lifetime compared to pristine BPQDs, suggesting slower electron–hole recombination. DFT and TD-DFT calculations revealed electronic structure details of the frontier molecular orbitals and electronic band gaps. The energy offsets of the highest occupied molecular orbital (ΔEHOMO = 0.40 eV) and the lowest unoccupied molecular orbital (ΔELUMO = 0.82 eV) in A-BPNSs, evidenced from the cyclic voltammetric experiments, were notably lower than the pristine BPQDs, making A-BPNSs more effective for organic photovoltaics. Stability studies revealed minimal degradation in A-BPNSs over ∼2 months, contrasting with a significant 52% degradation in pristine BPQDs within 6 days. The overall findings of this study are expected to contribute to the advancement of design strategies for efficient organic–inorganic photovoltaic devices.