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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:

Although significant progress has been made in the development of green, red, and near-infrared perovskite light-emitting diodes (PeLEDs), blue PeLEDs exhibit inferior performance, owing to various defects and poor carrier injection in solution-processed perovskite films. Thus, this study incorporates dual-passivation additive diphenylphosphinamide (DPPA) into perovskite films, and through density functional theory calculations and experimental characterizations, DPPA has been proven to be an effective passivator. Its phosphine oxide group coordinates with unsaturated lead ions, passivating perovskite defects, while the amino group forms hydrogen bonds with adjacent halide ions, suppressing their migration and further strengthening the passivation effect. Blue quasi-two-dimensional PeLEDs based on DPPA-modified perovskite films achieved an external quantum efficiency of 12.31% with an emission peak at 486 nm. Moreover, the device operational lifetime was extended by 32% with more stable spectra owing to the decreased defect density and suppressed ion migration in the perovskite film.