Shuaifeng Hu

Abstract:

Self-assembled monolayers (SAMs) have displayed great potential for improving efficiency and stability in p-i-n perovskite solar cells (PSCs). The anchoring of SAMs at the conductiv metal oxide substrates and their interaction with perovskite materials must be rationally tailored to ensure efficient charge carrier extraction and improved quality of the perovskite films. Herein, SAMs molecules with different anchoring groups and spacers to control the interaction with perovskite in the p-i-n mixed Sn-Pb PSCs are selected. It is found that the monolayer with the carboxylate group exhibits appropriate interaction and has a more favorable orientation and arrangement than that of the phosphate group. This results in reduced nonradiative recombination and enhanced crystallinity. In addition, the short chain length leads to an improved energy level alignment of SAMs with perovskite, improving hole extraction. As a result, the narrow bandgap (≈1.25 eV) Sn-Pb PSCs show efficiencies of up to 23.1% with an open-circuit voltage of up to 0.89 V. Unencapsulated devices retain 93% of their initial efficiency after storage in N₂ atmosphere for over 2500 h. Overall, this work highlights the underexplored potential of SAMs for perovskite photovoltaics and provides essential findings on the influence of their structural modification.

Abstract:

An open-cage bis[60]fulleroid (OC) was applied as electron transport material (ETM) in tin (Sn) halide perovskite solar cells (PSCs). Due to the reduced offset between the energy levels of Sn-based...

Abstract:

Monolithic all-perovskite triple-junction solar cells have the potential to deliver power conversion efficiencies beyond those of state-of-art double-junction tandems and well beyond the detailed-balance limit for single junctions. Today, however, their performance is limited by large deficits in open-circuit voltage and unfulfilled potential in both short-circuit current density and fill factor in the wide-bandgap perovskite sub cell. Here we find that halide heterogeneity—present even immediately following materials synthesis—plays a key role in interfacial non-radiative recombination and collection efficiency losses under prolonged illumination for Br-rich perovskites. We find that a diammonium halide salt, propane-1,3-diammonium iodide, introduced during film fabrication, improves halide homogenization in Br-rich perovskites, leading to enhanced operating stability and a record open-circuit voltage of 1.44 V in an inverted (p–i–n) device; ~86% of the detailed-balance limit for a bandgap of 1.97 eV. The efficient wide-bandgap sub cell enables the fabrication of monolithic all-perovskite triple-junction solar cells with an open-circuit voltage of 3.33 V and a champion PCE of 25.1% (23.87% certified quasi-steady-state efficiency).

Abstract:

The difference in encaged non-metallic element (i.e., C2 versus O) leads to clear change of intramolecular interactions and shifts in redox potentials of Lu2C2@C2(13333)-C74 and Lu2O@C2(13333)-C74, as a result of...