Twenty-micrometer-thick
single-crystal methylammonium lead triiodide
(MAPbI3) perovskite (as an absorber layer) grown on a charge-selective
contact using a solution space-limited inverse-temperature crystal
growth method yields solar cells with power conversion efficiencies
reaching 21.09% and fill factors of up to 84.3%. These devices set
a new record for perovskite single-crystal solar cells and open an
avenue for achieving high fill factors in perovskite solar cells.
Zero-dimensional perovskite-related structures (0D-PRS) are a new frontier of perovskite-based materials. 0D-PRS, commonly synthesized in powder form, manifest distinctive optical properties such as strong photoluminescence (PL), narrow emission linewidth, and high exciton binding energy. These properties make 0D-PRS compelling for several types of optoelectronic applications, including phosphor screens and electroluminescent devices. However, it would not be possible to rationally design the chemistry and structure of these materials, without revealing the origins of their optical behaviour, which is contradictory to the well-studied APbX3 perovskites. In this work, we synthesize single crystals of Cs4PbBr6 0D-PRS, and investigated the origins of their unique optical and electronic properties. The crystals exhibit a PL quantum yield higher than 40%, the highest reported for perovskite-based single crystals. Time-resolved and temperature dependent PL studies, supported by DFT calculations, and structural analysis, elucidate an emissive behaviour reminiscent of a quantum confined structure rather than a typical bulk perovskite material.
Defect passivation and surface modification of hybrid perovskite films are essential to achieving high power conversion efficiency (PCE) and stable perovskite photovoltaics. Here, we demonstrate a facile strategy that combines high PCE with high stability in CH 3 NH 3 PbI 3 (MAPbI 3 ) solar cells. The strategy utilizes inorganic perovskite quantum dots (QDs) to distribute elemental dopants uniformly across the MAPbI 3 film and attach ligands to the film's surface. Compared with pristine MAPbI 3 films, MAPbI 3 films processed with QDs show a reduction in tail states, smaller trap-state density, and an increase in carrier recombination lifetime. This strategy results in reduced voltage losses and an improvement in PCE from 18.3% to 21.5%, which is among the highest efficiencies for MAPbI 3 devices. Ligands introduced with the aid of the QDs render the perovskite film's surface hydrophobic-inhibiting moisture penetration. The devices maintain 80% of their initial PCE under 1-sun continuous illumination for 500 h and show improved thermal stability.
Lead
halide perovskite solar cells (PSCs) have advanced rapidly
in performance over the past decade. Single-crystal PSCs based on
micrometers-thick grain-boundary-free films with long charge carrier
diffusion lengths and enhanced light absorption (relative to polycrystalline
films) have recently emerged as candidates for advancing PSCs further
toward their theoretical limit. To date, the preferred method to grow
MAPbI3 single-crystal films for PSCs involves solution
processing at temperatures ≳120 °C, which adversely affects
the films’ crystalline quality, especially at the surface,
primarily because of methylammonium iodide loss at such high temperatures.
Here we devise a solvent-engineering approach to reduce the crystallization
temperature of MAPbI3 single-crystal films (<90 °C),
yielding better quality films with longer carrier lifetimes. Single-crystal
MAPbI3 inverted PSCs fabricated with this strategy show
markedly enhanced open-circuit voltages (1.15 V vs 1.08 V for controls),
leading to power conversion efficiencies of up to 21.9%, which are
among the highest reported for MAPbI3-based devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.