Modulating Crystallization and Defect Passivation by Butyrolactone Molecule for Perovskite Solar Cells.

The attainment of a well-crystallized photo-absorbing layer with minimal defects is crucial for achieving high photovoltaic performance in polycrystalline solar cells. However, in the case of perovskite solar cells (PSCs), precise control over crystallization and elemental distribution through solution processing remains a challenge. In this study, we propose the use of a multifunctional molecule, α-amino-γ-butyrolactone (ABL), as a modulator to simultaneously enhance crystallization and passivate defects, thereby improving film quality and deactivating nonradiative recombination centers in the perovskite absorber. The Lewis base groups present in ABL facilitate nucleation, leading to enhanced crystallinity, while also retarding crystallization. Additionally, ABL effectively passivates Pb2+ dangling bonds, which are major deep-level defects in perovskite films. This passivation process reduces recombination losses, promotes carrier transfer and extraction, and further improves efficiency. Consequently, the PSCs incorporating the ABL additive exhibit an increase in conversion efficiency from 18.30% to 20.36%, along with improved long-term environmental stability. We believe that this research will contribute to the design of additive molecular structures and the engineering of components in perovskite precursor colloids.

Hot-Carrier Injection Antennas with Hemispherical AgOx@Ag Architecture for Boosting the Efficiency of Perovskite Solar Cells.

In the past few years, the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have increased from 3.81 to 25.2%, surpassing those of all almost all thin films solar cells. For high-performance PSCs, it is pivotal to finely regulate the charge dynamics and light management between perovskite and charge-transfer materials to balance the trade-off between optical and electrical properties. In this study, a hemispherical core-shell silver oxide (AgOx) @ silver nanoparticles (Ag NPs) were grown onto the surface of the mesoporous titanium dioxide (m-TiO2) electron-transport layer (ETL) to improve the photogenerated charge transfer without sacrificing the stability of the devices. The results show that the electrical properties of m-TiO2 have been enhanced owing to the injection of a hot carrier in Ag NPs into the m-TiO2 ETL filling the trap states of m-TiO2. However, AgOx on the Ag NP surfaces can isolate the touch between Ag NPs and perovskite, thereby prohibiting the perovskite decomposition. Compared with the control device, the PCE was increased from 17.87 to 20.33% for the device with HOAPs. In the meantime, the long-term stability of the PSCs is not sacrificed, which is pivotal for fabricating PSCs and optoelectronic devices.