Shuaifeng Hu

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...

Abstract:

Computations of the molecular parameters and relative populations are reported for the two isomers of Er 3 N@C 80 experimentally known, i.e. produced by encapsulation into the isolated-pentagon-rule (IPR) C 80 cages with I h and D 5 h symmetries. The calculations are mostly based on the density-functional theory (DFT) treatments with the B3LYP functional. However, the inter-isomeric energetics is further refined with the B2PLYP method which places the D 5 h endohedral higher in the potential energy by 18.8 kcal/mol. The isomeric populations are evaluated using the Gibbs energy in a broad temperature interval. The computations performed with the floating-encapsulate-model (FEM) treatment agree with the observation that Er 3 N@ I h (7)-C 80 represents the major isomer. The calculations also suggest some similarity between Er 3 N@C 80 and Lu 3 N@C 80 so that Er 3 N@C 80 could possibly also produce a useful nanowire, like recently found with Lu 3 N@C 80 and its interesting electrical-conductivity and switching behavior.